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- Volume 98, Issue 5, 2018
The American Journal of Tropical Medicine and Hygiene - Volume 98, Issue 5, 2018
Volume 98, Issue 5, 2018
- Editorials
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- Perspective Piece
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Challenges in Assessing Combined Interventions to Promote Linear Growth
Abstract.Despite the recognition of stunting as a public health priority, nutritional and nonnutritional interventions to reduce or prevent linear growth failure have demonstrated minimal impact. Investigators and policymakers face several challenges that limit their ability to assess the potential benefits of combining available interventions into a linear growth promotion package. We use two common but very different interventions, deworming and multiple micronutrient supplements, to illustrate barriers to recommending an optimal linear growth promotion package based on the currently available literature. These challenges suggest that combining individual- and population-based as well as model-based approaches would complement existing research using systematic review, meta-analysis, and factorial randomized trials, and help integrate existing fields of research to inform the development of optimal linear growth promotion packages for children living in resource-limited settings.
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Barriers and Opportunities to Advancing Women in Leadership Roles in Vector Control: Perspectives from a Stakeholder Survey
Abstract.Increasing the active participation of professional women in vector control (VC) activities may help promote greater gender equity in the workplace and reduce the burden of vector-borne diseases. This stakeholder survey examined the current roles and perspective of professionals employed in the VC sector in Kenya, Indonesia, India, and other countries. The largest barriers that women face in pursuing leadership roles in the VC sector include lack of awareness of career opportunities, limitations based on cultural norms, and the belief that VC is men’s work. These barriers could be addressed through improving education and recruitment campaigns, as well as supporting higher education and mentoring programs. Females were almost six times more likely to be encouraged to pursue leadership positions in their organization compared with male respondents (odds ratio = 5.9, P > 0.03, 95% confidence interval: 1.19, 29.42). These findings suggest that once women are recruited into the VC workforce, they face minimal discrimination and have increased leadership opportunities.
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Trends in Public and Global Health Education among Nationally Recognized Undergraduate Liberal Arts Colleges in the United States
More LessAbstract.The prevalence of public health and global health (PH/GH) curricular offerings appear to be increasing in terms of undergraduate curricula and in the context of liberal arts education in the United States. Liberal arts colleges (LACs) represent stand-alone institutions, which exclusively focus on undergraduate education. The objective of this study was to assess the prevalence of PH/GH study pathways and PH/GH course offerings among LACs. All LACs identified through the US News and World Report (USNWR) college rankings were contacted with a survey about the following: formal majors, minors, or concentrations in PH/GH; independent study (IS) pathways for PH/GH; specific PH/GH courses offered; and the number of students graduating in 2016, 2017, and 2018 with formal and IS degrees in PH/GH. Demographic characteristics of the colleges came from the USNWR database. Almost half (43%) of all LACs in our sample offer a PH/GH major, minor, concentration, or IS pathway. Almost all (90%) colleges offer at least one course in PH/GH. Approximately 2,000 students attending these LACs pursued or are pursuing graduation with majors, minors, or concentrations in PH/GH for the years 2016–2018. The number of students pursuing formal PH/GH programs has increased by 25% from 2016 to 2018. Student interest in public health is rising in U.S. LACs, with more students seeking formal curricular or IS PH degree pathways. Public health messages are prevalent even among institutions without formal programs. Colleges without programs should consider integrating public health into their curriculum.
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Safe Water and Hygiene Integration with Human Immunodeficiency Virus and Antenatal Services: Leveraging Opportunities for Public Health Interventions and Improved Service Uptake
Abstract.Integrating public health interventions with antenatal clinic (ANC) visits may motivate women to attend ANC, thereby improving maternal and neonatal health, particularly for human immunodeficiency virus (HIV)-infected persons. In 2009, in an integrated ANC/Preventing Mother-to-Child Transmission program, we provided free hygiene kits (safe storage containers, WaterGuard water treatment solution, soap, and oral rehydration salts) to women at their first ANC visit and refills at subsequent visits. To increase fathers’ participation, we required partners’ presence for women to receive hygiene kits. We surveyed pregnant women at baseline and at 12-month follow-up to assess ANC service utilization, HIV counseling and testing (HCT), test drinking water for residual chlorine, and observe handwashing. We conducted in-depth interviews with pregnant women, partners, and health workers. We enrolled 106 participants; 97 (92%) were found at follow-up. During the program, 99% of pregnant women and their partners received HCT, and 99% mutually disclosed. Fifty-six percent of respondents had ≥ 4 ANC visits and 90% delivered at health facilities. From baseline to follow-up, the percentage of women who knew how to use WaterGuard (23% versus 80%, P < 0.0001), had residual chlorine in stored water (0% versus 73%, P < 0.0001), had confirmed WaterGuard use (0% versus 70%, P < 0.0003), and demonstrated proper handwashing technique (21% versus 64% P < 0.0001) increased. Program participants showed significant improvements in water treatment and hygiene, and high use of ANC services and HCT. This evaluation suggests that integration of hygiene kits, refills, and HIV testing during ANC is feasible and may help improve household hygiene and increase use of health services.
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Water, Sanitation, and Hygiene Practices Associated with Nutritional Status of Under-Five Children in Semi-Pastoral Communities Tanzania
More LessAbstract.Undernutrition among under-five children is a public health concern in developing countries and has been linked with poor water, sanitation, and hygiene (WASH) practices. This study aimed at assessing WASH practices and its association with nutritional status of under-five children in semi-pastoral communities of Arusha. The study was cross-sectional in design. Mother–child pairs from 310 households in four villages of Monduli and Longido were involved. Weight and height of children were measured using weighing scale and length/height board, respectively. Children’s age was recorded using clinic cards. Hemoglobin level of each child was tested using Hemo Cue® Hb 201 + photometer (HemoCue AB, Ängelholm, Sweden) machine. Structured questionnaire was used to gather information on WASH, child morbidity, demographic, and sociocultural characteristics. Prevalence of stunted, underweight, wasted, anemia, and diarrhea were 31.6%, 15.5%, 4.5% 61.2%, and 15.5%, respectively. Children with diarrhea 2 weeks preceding the survey (P = 0.004), children using surface water for domestic purposes (P < 0.001), and those with uneducated mothers (P = 0.001) had increased risk of being stunted and underweight. Children introduced to complementary foods before 6 months of age (P = 0.02) or belonging to polygamous families (P = 0.03) had increased risk of being stunted. Consumption of cow’s milk that is not boiled (P = 0.05) or being a boy (P = 0.03) was associated with underweight. Prevalence of undernutrition among under-five children in the population under study was alarming and it could be associated with poor WASH practices and other sociocultural factors. This study underlines the importance of incorporating WASH strategies in formulation of interventions targeting on promotion of nutrition and disease prevention in pastoral communities.
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Within-Compound Versus Public Latrine Access and Child Feces Disposal Practices in Low-Income Neighborhoods of Accra, Ghana
Abstract.In crowded urban settlements in low-income countries, many households rely on shared sanitation facilities. Shared facilities are not currently considered “improved sanitation” because of concerns about whether hygiene conditions sufficiently protect users from the feces of others. Prevention of fecal exposure at a latrine is only one aspect of sanitary safety. Ensuring consistent use of latrines for feces disposal, especially child feces, is required to reduce fecal contamination in households and communities. Household crowding and shared latrine access are correlated in these settings, rendering latrine use by neighbors sharing communal living areas as critically important for protecting one’s own household. This study in Accra, Ghana, found that household access to a within-compound basic latrine was associated with higher latrine use by children of ages 5–12 years and for disposal of feces of children < 5 years, compared with households using public latrines. However, within-compound access was not associated with improved child feces disposal by other caregivers in the compound. Feces was rarely observed in household compounds but was observed more often in compounds with latrines versus compounds relying on public latrines. Escherichia coli and human adenovirus were detected frequently on household surfaces, but concentrations did not differ when compared by latrine access or usage practices. The differences in latrine use for households sharing within-compound versus public latrines in Accra suggest that disaggregated shared sanitation categories may be useful in monitoring global progress in sanitation coverage. However, compound access did not completely ensure that households were protected from feces and microbial contamination.
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A Randomized Controlled Trial to Assess the Impact of Ceramic Water Filters on Prevention of Diarrhea and Cryptosporidiosis in Infants and Young Children—Western Kenya, 2013
Abstract.Cryptosporidium is a leading cause of diarrhea among Kenyan infants. Ceramic water filters (CWFs) are used for household water treatment. We assessed the impact of CWFs on diarrhea, cryptosporidiosis prevention, and water quality in rural western Kenya. A randomized, controlled intervention trial was conducted in 240 households with infants 4–10 months old. Twenty-six weekly household surveys assessed infant diarrhea and health facility visits. Stool specimens from infants with diarrhea were examined for Cryptosporidium. Source water, filtered water, and filter retentate were tested for Cryptosporidium and/or microbial indicators. To estimate the effect of CWFs on health outcomes, logistic regression models using generalized estimating equations were performed; odds ratios (ORs) and 95% confidence intervals (CIs) are reported. Households reported using surface water (36%), public taps (29%), or rainwater (17%) as their primary drinking water sources, with no differences in treatment groups. Intervention households reported less diarrhea (7.6% versus 8.9%; OR: 0.86 [0.64–1.16]) and significantly fewer health facility visits for diarrhea (1.0% versus 1.9%; OR: 0.50 [0.30–0.83]). In total, 15% of intervention and 12% of control stools yielded Cryptosporidium (P = 0.26). Escherichia coli was detected in 93% of source water samples; 71% of filtered water samples met World Health Organization recommendations of < 1 E. coli/100 mL. Cryptosporidium was not detected in source water and was detected in just 2% of filter rinses following passage of large volumes of source water. Water quality was improved among CWF users; however, the short study duration and small sample size limited our ability to observe reductions in cryptosporidiosis.
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Exploring Droughts and Floods and Their Association with Cholera Outbreaks in Sub-Saharan Africa: A Register-Based Ecological Study from 1990 to 2010
Abstract.Cholera outbreaks in Africa have been attributed to both droughts and floods, but whether the risk of a cholera outbreak is elevated during droughts is unknown. We estimated the risk of cholera outbreaks during droughts and floods compared with drought- and flood-free periods in 40 sub-Saharan African countries during 1990–2010 based on data from Emergency Events Database: the Office of Foreign Disaster Assistance /Centre for Research on the Epidemiology of Disasters International Disaster Database (www.emdat.be). A cholera outbreak was registered in one of every three droughts and one of every 15 floods. We observed an increased incidence rate of cholera outbreaks during drought periods (incidence rate ratio [IRR] = 4.3, 95% confidence interval [CI] = 2.9–7.2) and during flood periods (IRR = 144, 95% CI = 101–208) when compared with drought/flood-free periods. Floods are more strongly associated with cholera outbreaks, yet the prevalence of cholera outbreaks is higher during droughts because of droughts’ long durations. The results suggest that droughts in addition to floods call for increased cholera preparedness.
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Seroprevalence of Hepatitis A Virus, Hepatitis E Virus, and Helicobacter pylori in Rural Communities of the Bolivian Chaco, 2013
Abstract.In the Bolivian Chaco, south-east of Bolivia, studies conducted over the past three decades reported hepatitis A virus (HAV) and Helicobacter pylori seroprevalences above 90% and 60%, respectively. Hepatitis E virus (HEV) prevalence was previously found to be 6–7% but is probably an underestimate because of the poor sensitivity of the assays used. In November 2013, we conducted a cross-sectional study of 263 healthy volunteers from two rural communities of the Bolivian Chaco, aiming to reassess HAV, HEV, and H. pylori seroprevalence 10–20 years following the previous surveys. Hepatitis A virus seroprevalence was 95%, with universal exposure after the first decade of life; HEV seroprevalence was considerably higher (31–35%) than that previously reported; H. pylori seroprevalence was 59%, with an age-dependent distribution. The high prevalence of these infections suggests that major efforts are still needed to reduce fecal–oral transmission and to improve human health in the Bolivian Chaco.
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Leptospirosis Outbreak After the 2014 Major Flooding Event in Kelantan, Malaysia: A Spatial-Temporal Analysis
Abstract.Severe floods increase the risk of leptospirosis outbreaks in endemic areas. This study determines the spatial-temporal distribution of leptospirosis in relation to environmental factors after a major flooding event in Kelantan, Malaysia. We conducted an observational ecological study involving incident leptospirosis cases, from the 3 months before, during, and three months after flood, in reference to the severe 2014 Kelantan flooding event. Geographical information system was used to determine the spatial distribution while climatic factors that influenced the cases were also analyzed. A total of 1,229 leptospirosis cases were notified within the three study periods where incidence doubled in the postflood period. Twelve of 66 subdistricts recorded incidence rates of over 100 per 100,000 population in the postflood period, in comparison with only four subdistricts in the preflooding period. Average nearest neighborhood analysis indicated that the cases were more clustered in the postflood period as compared with the preflood period, with observed mean distance of 1,139 meters and 1,666 meters, respectively (both at P < 0.01). Global Moran’s I was higher in the postflood period (0.19; P < 0.01) as compared with the preflood period (0.06; P < 0.01). Geographic weighted regression showed that living close to water bodies increased the risk of contracting the disease. Postflooding hotspots were concentrated in areas where garbage cleanup occurred and the incidence was significantly associated with temperature, humidity, rainfall, and river levels. Postflooding leptospirosis outbreak was associated with several factors. Understanding the spatial distribution and associated factors of leptospirosis can help improve future disease outbreak management after the floods.
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Epidemiological and Clinical Features of Melioidosis: A Report of Seven Cases from Southern Inland China
More LessAbstract.Some subtropical regions with similar climatic conditions to melioidosis-endemic areas, such as southern Guangxi, may be new endemic zones for melioidosis. We retrospectively reviewed seven culture-proven melioidosis patients from October 2006 to March 2015. Their clinical characteristics, diagnosis, and treatment, and the geographical and environmental factors were analyzed. Seven male patients lived at latitudes of 21–23°N in Beihai, Nanning, Chongzuo City of the Guangxi Province. Symptom onset occurred during the rainy season. All patients had pneumonia, six patients had diabetes, five patients had a history of wounds or exposure to soil or water, and two patients had liver and spleen abscesses. Most patients were misdiagnosed before the confirmatory laboratory testing. The final diagnosis was confirmed as melioidosis by isolation of Burkholderia pseudomallei in a culture of blood or pus. The 6- to 17-month treatment included carbapenems, ceftazidime, or other antibiotics active against the organism in vitro. All patients initially appeared cured, but two subsequently had recurrent melioidosis. In non-highly endemic areas, there is often a lack of awareness of melioidosis, and this leads to misdiagnoses. Other subtropical regions with climatic conditions similar to the highly melioidosis-endemic areas such as southern Guangxi may also be melioidosis endemic.
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Use of Rapid Enzyme-Linked Immunosorbent Assays for Serological Screening of Melioidosis in Myanmar
Abstract.Burkholderia pseudomallei, the etiologic agent of melioidosis, is an important but under-recognized cause of disease in the tropics. Although first described over a century ago as a septicemic illness associated with morphine addicts in Rangoon, Burma, there is little information regarding the incidence of melioidosis in present-day Myanmar. To address this issue, we used two recently developed and validated serological assays to detect B. pseudomallei–specific antibodies in 124 serum samples obtained from febrile patients in the delta region of Myanmar. Using cutoff values derived from culture-confirmed melioidosis cases in neighboring Thailand, 3.2% of the samples exhibited reactivity profiles consistent with active B. pseudomallei infections. Collectively, these findings indicate that melioidosis likely represents a significant cause of morbidity and mortality in Myanmar and support the need for further studies to assess the true burden of disease in this country.
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Detection of Histoplasma capsulatum in Organic Fertilizers by Hc100 Nested Polymerase Chain Reaction and Its Correlation with the Physicochemical and Microbiological Characteristics of the Samples
Abstract.Histoplasma capsulatum is the causative agent of histoplasmosis and this fungus inhabits soils rich in phosphorus and nitrogen that are enriched with bird and bat manure. The replacement of organic matter in agroecosystems is necessary in the tropics, and the use of organic fertilizers has increased. Cases and outbreaks due to the presence of the fungus in these components have been reported. The Instituto Colombiano Agropecuario resolution 150 of 2003 contains the parameters set by the Colombian Technical Standard (NTC 5167) on the physicochemical and microbiological features of fertilizers, but it does not regulate the search for H. capsulatum. The aim of this study was to demonstrate H. capsulatum presence in organic fertilizers by nested polymerase chain reaction (PCR). A total of 239 samples were collected: 201 (84.1%) corresponded to organic fertilizers, 30 (12.5%) to bird excrement, and 8 (3.4%) to cave soils. The Hc100 nested PCR had a detection limit of 0.1 pg/µL and a specificity of 100%. A total of 25 (10.5%) samples were positive and validated by sequencing. Seven of the positive samples represented locations where H. capsulatum was previously detected, suggesting the persistence of the fungus. No significant correlations were detected between the physicochemical and microbiological parameters with the presence of H. capsulatum by nested PCR, indicating the fungus existence in organic fertilizers that complied with the NTC 5167. The Hc100 nested PCR targeting H. capsulatum standardized in this work will improve the evaluation of organic fertilizers and ensure the prevention of outbreaks and cases due to manufacturing, marketing, and use of fertilizers contaminated with H. capsulatum.
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Case Report: Diffuse Cutaneous Leishmaniasis by Leishmania infantum in a Patient Undergoing Immunosuppressive Therapy: Risk Status in an Endemic Mediterranean Area
Abstract.This case report highlights the risk of severe cutaneous leishmaniasis (CL) by Leishmania infantum in patients undergoing immunosuppressant therapy who either live in an endemic area or are visiting in the transmission season. The case patient, resident in Majorca (Balearic Islands), presented 12 disseminated erythematous skin lesions, 1–6 cm in diameter, located on the scalp, cheek, umbilical region, and lower extremities 8 years after undergoing anti–tumor necrosis factor (TNF) therapy. Parasite presence in peripheral blood and high levels of specific antibodies were also observed, indicating a possible risk of CL shifting toward a visceral infection. However, once CL was diagnosed, anti-TNF therapy was discontinued and liposomal amphotericin B was administered, resulting in a complete healing of lesions, no Leishmania DNA detection in blood, and an important serological decrease in antibodies. The lack of data on the supposed epidemiological association between leishmaniasis and immunosuppressive therapy highlights the importance of implementing surveillance systems in endemic areas. No obvious relationship was found based on the data provided by the Balearic Islands Epidemiological System, in contrast with data reported in nearby endemic areas. This indicates that if the suspected association is to be clarified, greater efforts are needed to report information about concomitant diseases and therapies in leishmaniasis patients.
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The Elderly Respond to Antimony Therapy for Cutaneous Leishmaniasis Similarly to Young Patients but Have Severe Adverse Reactions
Abstract.There is evidence that elderly patients with cutaneous leishmaniasis (CL) have more mucosal and disseminated diseases than young patients and their cells produce less antigen-induced interferon (IFN)-γ. Herein, we compared the roles of interleukin (IL)-10 and IL-15 as modulators of antigen-induced immune responses and the incidence of adverse reaction and response to therapy in young versus elderly patients with CL. Study participants included 35 senior (60–85 years) and 35 young (18–40 years) patients who had a diagnosis of CL documented by typical cutaneous lesions containing Leishmania braziliensis DNA. Elderly patients had less lymph node enlargement. Antigen-induced blood cell cytokine responses were studied in the absence or presence of IL-10 antibody or exogenously added recombinant IL-15. The ratio of IFN-γ/IL-10 was lower in elderly patients, and IFN-γ production was enhanced by either neutralization of IL-10 or exogenous recombinant IL-15 in blood cells from elderly but not young patients. Patients were treated three times weekly with antimony at 20 mg/kg/day for 20 doses. Although there was no difference in response to therapy between the two groups, two young patients needed rescue therapy with amphotericin B. Ventricular arrhythmias and ventricular overload were more frequent in elderly patients. We conclude that elderly patients have alterations in the immune response that may influence clinical manifestations, but we did not find that they had a higher failure rate than young subjects to antimony therapy. However, because of the high rate of electrocardiographic abnormalities during therapy, antimony should not be used in elderly patients with CL.
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Analytical Performance of a Loop-Mediated Isothermal Amplification Assay for Leishmania DNA Detection in Sandflies and Direct Smears of Patients with Cutaneous Leishmaniasis
Abstract.Loop-mediated isothermal amplification (LAMP) is ideal for the detection of Leishmania DNA as it is a quick and easy-to-perform test that does not require complex or sophisticated equipment or infrastructure. However, the application of this technique in the detection of Leishmania DNA has not been comprehensively analyzed to date (analytical validation). Our objective was to evaluate the sensitivity and analytical specificity (anticipated reportable range [ARR], the limit of detection [LoD], and accuracy) of LAMP targeting the 18S rRNA gene in the diagnosis of six New World Leishmania species. We then applied the validated LAMP assay across 50 samples of sandflies and 50 direct smears from a recent outbreak of cutaneous leishmaniasis in Colombia to determine its diagnostic performance. The LAMP assay exclusively amplified the DNA of Leishmania spp., and an ARR of between 1 × 104 and 1 × 10−2 equivalent parasites/mL was determined. An LoD of 1 × 10−2 equivalent parasites/mL was established and there was no statistically significant variation in terms of accuracy. Finally, a sensitivity of 100% in direct smears and sandflies samples was calculated and a specificity of 90.9% for direct smears using microscopy as reference and 96.8% for sandflies using real-time polymerase chain reaction as reference were determined. To our knowledge, this is the first attempt to analytically validate a LAMP test to detect Leishmania DNA, which showed good diagnostic potential from sandflies and direct smear samples.
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Safety Analysis of Leishmania Vaccine Used in a Randomized Canine Vaccine/Immunotherapy Trial
Abstract.In Leishmania infantum–endemic countries, controlling infection within dogs, the domestic reservoir, is critical to public health. There is a need for safe vaccines that prevent canine progression with disease and transmission to others. Protective vaccination against Leishmania requires mounting a strong, inflammatory, Type 1 response. Three commercially available canine vaccines on the global veterinary market use saponin or inflammatory antigen components (Letifend) as a strong pro-inflammatory adjuvant. There is very little information detailing safety of saponin as an adjuvant in field trials. Safety analyses for the use of vaccine as an immunotherapeutic in asymptomatically infected animals are completely lacking. Leishmania infantum, the causative agent of canine leishmaniasis, is enzootic within U.S. hunting hounds. We assessed the safety of LeishTec® after use in dogs from two different clinical states: 1) without clinical signs and tested negative on polymerase chain reaction and serology or 2) without clinical signs and positive for at least one Leishmania diagnostic test. Vaccine safety was assessed after all three vaccinations to quantify the number and severity of adverse events. Vaccinated animals had an adverse event rate of 3.09%, whereas placebo animals had 0.68%. Receiving vaccine was correlated with the occurrence of mild, site-specific, reactions. Occurrence of severe adverse events was not associated with having received vaccine. Infected, asymptomatic animals did not have a higher rate of adverse events. Use of vaccination is, therefore, likely to be safe in infected, asymptomatic animals.
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Natural Infection of Phlebotomus sergenti by Leishmania tropica in Libya
Abstract.Cutaneous Leishmaniasis (CL) is a public health concern caused by Leishmania (L.) major and L. tropica in Libya. Information on sandfly vectors, as well as their associated Leishmania species, is of paramount importance because vector dispersion is one of the major factors responsible for pathogen dissemination. A number of 515 sandflies (275 males and 240 females) were collected during June–November 2012 using the Centers for Disease Control miniature light traps from Al Rabta, northwest of Libya. Two hundred and forty unfed females were identified; Phlebotomus (Ph.) papatasi (N = 97), Ph. sergenti (N = 27), Ph. longicuspis (N = 32), Sergentomyia (Se.) minuta (N = 38), and Se. fallax (N = 46). These flies were screened for Leishmania DNA using the polymerase chain reaction–restriction fragment length polymorphism analysis of the internal transcribed spacer 1 and sequencing. Two Ph. sergenti were found positive to L. tropica DNA. This finding should be considered for any further vector surveillance and epidemiological studies of CL in endemic areas across Libya.
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The Impact of Periodic Distribution Campaigns of Long-Lasting Insecticidal-Treated Bed Nets on Malaria Vector Dynamics and Human Exposure in Dielmo, Senegal
Abstract.The implementation of long-lasting insecticidal-treated bed nets (LLINs) has contributed to halving the mortality rate due to malaria since 2000 in sub-Saharan Africa. These tools are highly effective against indoor-feeding malaria vectors. Thus, to achieve the World Health Assembly’s new target to reduce the burden of malaria over the next 15 years by 90%, it is necessary to understand how the spatiotemporal dynamics of malaria vectors and human exposure to bites is modified in the context of scaling up global efforts to control malaria transmission. This study was conducted in Dielmo, a Senegalese village, after the introduction of LLINs and two rounds of LLINs renewals. Data analysis showed that implementation of LLINs correlated with a significant decrease in the biting densities of the main malaria vectors, Anopheles gambiae s.l. and Anopheles funestus, reducing malaria transmission. Other environment factors likely contributed to the decrease in An. funestus, but this trend was enhanced with the introduction of LLINs. The bulk of bites occurred during sleeping hours, but the residual vector populations of An. gambiae s.l. and An. funestus had an increased propensity to bite outdoors, so a risk of infectious bites remained for LLINs users. These results highlight the need to increase the level and correct use of LLINs and to combine this intervention with complementary control measures against residual exposure, such as spatial repellents and larval source management, to achieve the goal of eliminating malaria transmission.
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Evaluation of Malaria Urban Risk Using an Immuno-Epidemiological Biomarker of Human Exposure to Anopheles Bites
Abstract.Urban malaria is an underestimated serious health concern in African countries. This study aimed to evaluate the risk of malaria transmission in an urban area by evaluating the level of human exposure to Anopheles bites using an Anopheles salivary biomarker (gambiae Salivary Gland Protein-6 peptide 1 [gSG6-P1] peptide). Two multidisciplinary cross-sectional studies were undertaken in five sites of Bouaké city (three urban districts and two surrounding villages, used as control; Côte d’Ivoire) during the rainy season and the dry season. Blood samples were obtained from children 6 months to 14 years of age for immunological tests. The level of anti-gSG6-P1 immunoglobulin G (IgG) antibodies was significantly higher in the rainy season than the dry season in both urban and rural sites (P < 0.0001). Interestingly, children with the highest anti-gSG6-P1 IgG responses in the rainy season were infected by Plasmodium falciparum. Surprisingly, no difference of anti-gSG6-P1 IgG level was observed between urban and rural areas, for either season. The current data suggest that children in the urban city of Bouaké could be as highly exposed to Anopheles bites as children living in surrounding villages. The immunological biomarker of human exposure to Anopheles bites may be used to accurately assess the potential risk of malaria transmission in African urban settings.
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Polymorphisms in the K13 Gene in Plasmodium falciparum from Different Malaria Transmission Areas of Kenya
Abstract.The development of artemisinin (ART)-resistant parasites in Southeast Asia (SEA) threatens malaria control globally. Mutations in the Kelch 13 (K13)-propeller domain have been useful in identifying ART resistance in SEA. ART combination therapy (ACT) remains highly efficacious in the treatment of uncomplicated malaria in Sub-Saharan Africa (SSA). However, it is crucial that the efficacy of ACT is closely monitored. Toward this effort, this study profiled the prevalence of K13 nonsynonymous mutations in different malaria ecological zones of Kenya and in different time periods, before (pre) and after (post) the introduction of ACT as the first-line treatment of malaria. Nineteen nonsynonymous mutations were present in the pre-ACT samples (N = 64) compared with 22 in the post-ACT samples (N = 251). Eight of these mutations were present in both pre- and post-ACT parasites. Interestingly, seven of the shared single-nucleotide polymorphisms were at higher frequencies in the pre-ACT than the post-ACT parasites. The A578S mutation reported in SSA and the V568G mutation reported in SEA were found in both pre- and post-ACT parasites, with their frequencies declining post-ACT. D584Y and R539K mutations were found only in post-ACT parasites; changes in these codons have also been reported in SEA with different amino acids. The N585K mutation described for the first time in this study was present only in post-ACT parasites, and it was the most prevalent mutation at a frequency of 5.2%. This study showed the type, prevalence, and frequency of K13 mutations that varied based on the malaria ecological zones and also between the pre- and post-ACT time periods.
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Knowledge and Adherence to the National Guidelines for Malaria Diagnosis in Pregnancy among Health-Care Providers and Drug-Outlet Dispensers in Rural Western Kenya
Abstract.Prompt diagnosis and effective treatment of acute malaria in pregnancy (MiP) is important for the mother and fetus; data on health-care provider adherence to diagnostic guidelines in pregnancy are limited. From September to November 2013, a cross-sectional survey was conducted in 51 health facilities and 39 drug outlets in Western Kenya. Provider knowledge of national diagnostic guidelines for uncomplicated MiP were assessed using standardized questionnaires. The use of parasitologic testing was assessed in health facilities via exit interviews with febrile women of childbearing age and in drug outlets via simulated-client scenarios, posing as pregnant women or their spouses. Overall, 93% of providers tested for malaria or accurately described signs and symptoms consistent with clinical malaria. Malaria was parasitologically confirmed in 77% of all patients presenting with febrile illness at health facilities and 5% of simulated clients at drug outlets. Parasitological testing was available in 80% of health facilities; 92% of patients evaluated at these facilities were tested. Only 23% of drug outlets had malaria rapid diagnostic tests (RDTs); at these outlets, RDTs were offered in 17% of client simulations. No differences were observed in testing rates by pregnancy trimester. The study highlights gaps among health providers in diagnostic knowledge and practice related to MiP, and the lack of malaria diagnostic capacity, particularly in drug outlets. The most important factor associated with malaria testing of pregnant women was the availability of diagnostics at the point of service. Interventions that increase the availability of malaria diagnostic services might improve malaria case management in pregnant women.
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Development of Visually Improved Loop Mediated Isothermal Amplification for the Diagnosis of Plasmodium vivax Malaria in a Tertiary Hospital in Chandigarh, North India
More LessAbstract.More than 80% of the global burden of the Plasmodium vivax is contributed by mainly three countries (India, Indonesia, and Pakistan). Reports from last decades have highlighted the occurrence of severe P. vivax malaria which was earlier considered to be benign. The recent trends of increasing P. vivax–associated morbidity and mortality emphasizes the need for early and accurate diagnosis of P. vivax malaria for the timely management of patients. Microscopy is considered a gold standard but needs experienced laboratory technologists. Over the last few years, Polymerase chain reaction (PCR) is being used as a highly sensitive and specific test but it requires expensive equipment which limits its use in the field. Therefore, in the present study, utility of visually improved loop-mediated isothermal amplification (LAMP) for the detection of P. vivax was evaluated targeting 18SrRNA gene in 145 microscopically confirmed P. vivax and 20 P. vivax negative patients. Sensitivity and specificity of LAMP was assessed with respect to microscopy and multiplex nested PCR (nPCR). Results of the LAMP assay was also correlated with rapid diagnostic test, multiplex nPCR and real-time PCR results. Overall, sensitivity and specificity of P. vivax–specific LAMP compared with microscopy were found to be 100% and 85%, respectively. Furthermore, detection limit for LAMP was found to be 0.8 copies/μL and it was also able to detect three complicated cases of P. vivax which were missed by microscopy. This study showed a LAMP assay to be a rapid and very sensitive method for the early diagnosis of both complicated and uncomplicated P. vivax malaria.
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Efficiency of a Malaria Reactive Test-and-Treat Program in Southern Zambia: A Prospective, Observational Study
Abstract.To improve malaria surveillance and achieve elimination, the Zambian National Malaria Elimination Program implemented a reactive test-and-treat program in Southern Province in 2013 in which individuals with rapid diagnostic test (RDT)–confirmed malaria are followed-up at their home within 1 week of diagnosis. Individuals present at the index case household and those residing within 140 m of the index case are tested with an RDT and treated with artemether–lumefantrine if positive. This study evaluated the efficiency of this reactive test-and-treat strategy by characterizing infected individuals missed by the RDT and the current screening radius. The radius was expanded to 250 m, and a quantitative polymerase chain reaction (qPCR) test was performed on dried blood spot specimens. From January 2015 through March 2016, 145 index cases were identified at health centers and health posts. A total of 3,333 individuals residing in 525 households were screened. Excluding index cases, the parasite prevalence was 1.1% by RDT (33 positives of 3,016 participants) and 2.4% by qPCR (73 positives of 3,016 participants). Of the qPCR-positive cases, 62% of 73 individuals tested negative by RDT. Approximately half of the infected individuals resided within the index case household (58% of RDT-positive individuals and 48% of qPCR-positive individuals). The low sensitivity of the RDT and the high proportion of secondary cases within the index case household decreased the efficiency of this reactive test-and-treat strategy. Reactive focal drug administration in index case households would be a more efficient approach to treating infected individuals associated with a symptomatic case.
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Characterization of Plasmodium Lactate Dehydrogenase and Histidine-Rich Protein 2 Clearance Patterns via Rapid On-Bead Detection from a Single Dried Blood Spot
Abstract.A rapid, on-bead enzyme-linked immunosorbent assay for Plasmodium lactate dehydrogenase (pLDH) and Plasmodium falciparum histidine-rich protein 2 (HRP2) was adapted for use with dried blood spot (DBS) samples. This assay detected both biomarkers from a single DBS sample with only 45 minutes of total incubation time and detection limits of 600 ± 500 pM (pLDH) and 69 ± 30 pM (HRP2), corresponding to 150 and 24 parasites/μL, respectively. This sensitive and reproducible on-bead detection method was used to quantify pLDH and HRP2 in patient DBS samples from rural Zambia collected at multiple time points after treatment. Biomarker clearance patterns relative to parasite clearance were determined; pLDH clearance followed closely with parasite clearance, whereas most patients maintained detectable levels of HRP2 for 35–52 days after treatment. Furthermore, weak-to-moderate correlations between biomarker concentration and parasite densities were found for both biomarkers. This work demonstrates the utility of the developed assay for epidemiological study and surveillance of malaria.
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Impact of Four Years of Annual Mass Drug Administration on Prevalence and Intensity of Schistosomiasis among Primary and High School Children in Western Kenya: A Repeated Cross-Sectional Study
Abstract.Schistosomiasis remains a major public health problem in Kenya. The World Health Organization recommends preventive chemotherapy with praziquantel (PZQ) to control morbidity due to schistosomiasis. Morbidity is considered linked to intensity of infection, which along with prevalence is used to determine the frequency of mass drug administration (MDA) to school-age children. We determined the impact of annual school-based MDA on children across all primary and high school years using a repeated cross-sectional study design in five schools near Lake Victoria in western Kenya, an area endemic for Schistosoma mansoni. At baseline and for the following four consecutive years, between 897 and 1,440 school children in Grades 1–12 were enrolled and evaluated by Kato-Katz for S. mansoni and soil-transmitted helminths (STH), followed by annual MDA with PZQ and albendazole. Four annual rounds of MDA with PZQ were associated with reduced S. mansoni prevalence in all school children (44.7–14.0%; P < 0.001) and mean intensity of infection by 91% (90.4 to 8.1 eggs per gram [epg] of stool; P < 0.001). Prevalence of high-intensity infection (≥ 400 epg) decreased from 6.8% at baseline to 0.3% by the end of the study. Soil-transmitted helminth infections, already low at baseline, also decreased significantly over the years. In this high prevalence area, annual school-based MDA with high coverage across all Grades (1–12) resulted in rapid and progressive declines in overall prevalence and intensity of infection. This decrease was dramatic in regard to heavy infections in older school-attending children.
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Case Report: Role of Interventional Radiology in the Management of Patients with Alveolar Echinococcus: Successful Management of Three Cases
More LessAbstract.Alveolar echinococcus (AE) is an infestation by Echinococcus multilocularis. Partial hepatectomy or liver transplantation is the first choice of treatment. However, the disease is usually diagnosed at an unresectable stage. In those cases, invasion of the bile ducts and vessels, and necrosis in the center of the lesion lead to severe complications, such as cholangitis and liver abscesses. Palliative surgery has been reported to not offer advantages in management, and percutaneous and endoscopic interventions have become more prominent in management. In this case series, outcomes in three cases with unresectable AE were reported. In one of the cases, interventional procedures were used to manage the complications after surgery. In the second case, the cystic component was aspirated to decrease the size before the surgery and in the third case, it was used to drain biliary tree and no surgery was done.
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Detection of Immunoglobulin G Antibodies to Taenia solium Cysticercosis Antigen Glutathione-S-Transferase–rT24H in Malian Children Using Multiplex Bead Assay
Abstract.Blood samples from 805 students attending 42 elementary schools in Mopti, Sikasso, and Koulikoro regions, and Bamako district in Mali participated in a school water, sanitation, and hygiene intervention. Immunoglobulin (Ig) G responses to several antigens/pathogens were assessed by a multiplex bead assay (MBA), and the recombinant Taenia solium T24H antigen was included. Of all students tested, 8.0% were positive to rT24H, but in some schools 25–30%. A cluster of 12 widespread school locations showed not only a relative risk of 3.23 for T. solium exposure and significantly higher IgG responses (P < 0.001) but also significantly lower elevation (P = 0.04) (m, above sea level) compared with schools outside the cluster. All schools at elevations < 425 m showed significantly higher IgG responses (P = 0.017) than schools at elevations ≥ 425 m. The MBA is an excellent serological platform that provides cost-effective opportunities to expand testing in serosurveys.
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What It Means to Be Guinea Worm Free: An Insider’s Account from Ghana’s Northern Region
Abstract.Despite several periods of stagnating guinea worm disease (GWD) incidence in Ghana during its national eradication campaign in the 1990s and early 2000s, the last reported case of GWD was in May 2010. In July 2011, Ghana celebrated the interruption of guinea worm (GW) transmission. Although it has been established that GWD causes disability, pain, and socioeconomic hardship, there is a dearth of population-based evidence collected in post-GW–endemic countries to document the value attributed to GWD eradication by residents in formerly endemic communities. Given Ghana’s recent history of GWD and a concentrated burden of the disease in its Northern Region, a pattern which remained true through to the final stage of the eradication campaign, seven villages in the Northern Region were targeted for a retrospective, cross-sectional study to detail the perceptions, attitudes, and beliefs about the impact of eradication of GWD in northern Ghana. The study revealed that respondents from the sampled communities felt GW eradication improved their socioeconomic conditions, as the impact of infection prohibited the pursuit of individual and social advancement. The value residents placed on the absence of GWD highlights both the impact infection had on the pursuit of social and economic advancement and the newfound ability to be disease-free and productive. Of the 143 respondents, 133 had GWD in the past and were incapacitated for an average of 6 weeks annually per GW infection, with each infected person affected nearly four times in his or her lifetime.
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Albendazole Treatment Improves Work Capacity in Women Smallholder Farmers Infected with Hookworm: A Double-Blind Randomized Control Trial
Abstract.An estimated 4.7 billion people live in regions exposed to soil-transmitted helminths, intestinal parasites that have significant impacts on the health of women smallholder farmers. The goal of this trial was to determine whether treatment with albendazole impacts the work capacity of these farmers. This is a prospective double-blind, randomized effectiveness trial. Participants (N = 250) were randomly selected from safe motherhood groups in the Democratic Republic of Congo. Prevalence/intensity of hookworm infection, hemoglobin, and demographics was obtained. At study (Time = 0), participants were randomized into treatment (albendazole 400 mg) and placebo (similar placebo tablet) groups. A step test was administered as a proxy metric for work capacity. Work capacity was defined as ∆heart rate before and after 3 minutes of step testing, in beats per minute. At study (time = 7 months), the step test was repeated and work capacity remeasured. The ∆work capacity (time = 0 minus time = 7 months) was the primary outcome. Investigators/field assistants were blinded to who was enrolled in groups, hookworm status, and step test results. Regression showed highly significant interactive effects of hookworm status and treatment group relative to ∆work capacity after controlling for resting pulse rate and age (P < 0.002). Estimated marginal means for work capacity (WC) for each of four groups (hookworm positive plus placebo, hookworm positive plus treatment, hookworm negative plus placebo, and hookworm negative plus treatment) showed women who were hookworm positive and received treatment decreased heart rate by 9.744 (95% confidence interval [CI]: 6.42, 13.07) beats per minute (increased WC), whereas women who were hookworm positive and received placebo saw a nonsignificant decrease of 0.034 (95% CI: −3.16, 3.84) beats per minute. Treatment with albendazole was associated with improved aerobic work capacity posttreatment. Given modest costs of drug distributions, risk benefits of periodic deworming warrants further study in larger controlled trials.
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Comparison of PCR Methods for Onchocerca volvulus Detection in Skin Snip Biopsies from the Tshopo Province, Democratic Republic of the Congo
Abstract.Defining the optimal diagnostic tools for evaluating onchocerciasis elimination efforts in areas co-endemic for other filarial nematodes is imperative. This study compared three published polymerase chain reaction (PCR) methods: the Onchocerca volvulus–specific qPCR-O150, the pan-filarial qPCR melt curve analysis (MCA), and the O150-PCR enzyme-linked immunosorbent assay (ELISA) currently used for vector surveillance in skin snip biopsies (skin snips) collected from the Democratic Republic of the Congo. The pan-filarial qPCR-MCA was compared with species-specific qPCRs for Loa loa and Mansonella perstans. Among the 471 skin snips, 47.5%, 43.5%, and 27.0% were O. volvulus positive by qPCR-O150, qPCR-MCA, and O150-PCR ELISA, respectively. Using qPCR-O150 as the comparator, the sensitivity and specificity of qPCR-MCA were 89.3% and 98.0%, respectively, whereas for O150-PCR ELISA, they were 56.7% and 100%, respectively. Although qPCR-MCA identified the presence of L. loa and Mansonella spp. in skin snips, species-specific qPCRs had greater sensitivity and were needed to identify M. perstans. Most of the qPCR-MCA misclassifications occurred in mixed infections. The reduced sensitivity of O150-PCR ELISA was associated with lower microfilaria burden and with lower amounts of O. volvulus DNA. Although qPCR-MCA identified most of the O. volvulus–positive skin snips, it is not sufficiently robust to be used for stop-mass drug administration (MDA) evaluations in areas co-endemic for other filariae. Because O150-PCR ELISA missed 43.3% of qPCR-O150–positive skin snips, the qPCR-O150 assay is more appropriate for evaluating skin snips of OV-16 + children in stop-MDA assessments. Although improving the sensitivity of the O150-PCR ELISA as an alternative to qPCR might be possible, qPCR-O150 offers distinct advantages aside from increased sensitivity.
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Phase I Randomized Study of a Tetravalent Dengue Purified Inactivated Vaccine in Healthy Adults from Puerto Rico
Abstract.The safety and immunogenicity of four adjuvanted formulations of an investigational tetravalent dengue purified inactivated vaccine (DPIV) were evaluated in a predominantly dengue-primed population in Puerto Rico. In this placebo-controlled, randomized, observer-blind, phase I trial, 100 healthy adults were randomized 1:1:1:1:1 to receive DPIV at Day (D)0 and D28 (1 μg per dengue virus [DENV] type 1–4 adjuvanted with either alum, AS01E or AS03B, or 4 μg per DENV type adjuvanted with alum) or saline placebo. Functional antibody responses were assessed using a microneutralization assay at D56, Month (M)7, and M13. All DPIV formulations were well tolerated and no safety signals were identified through M13. The M13 according-to-protocol (ATP) immunogenicity cohort included 83 participants. The ATP analysis of immunogenicity was performed only on the 78 subjects seropositive for ≥ 1 DENV type at baseline: 69 tetravalent, three trivalent, two bivalent, and four monovalent. In all DPIV groups, geometric mean antibody titers (GMTs) increased from D0 to D56 and waned modestly through M13, while remaining well above prevaccination levels. The 4 μg + alum and the AS01E- and AS03B-adjuvanted formulations were highly immunogenic, with M13-neutralizing antibody GMTs against all four DENV types above 1,000. M13/D0 GMT ratios were highest in the 1 μg + AS03B group (ranging 3.2–3.7 depending on the DENV type). These results encourage continued clinical development of DPIV (ClinicalTrials.gov: NCT01702857).
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The Burden of Dengue Fever and Chikungunya in Southern Coastal Ecuador: Epidemiology, Clinical Presentation, and Phylogenetics from the First Two Years of a Prospective Study
Anna M. Stewart-Ibarra, Sadie J. Ryan, Aileen Kenneson, Christine A. King, Mark Abbott, Arturo Barbachano-Guerrero, Efraín Beltrán-Ayala, Mercy J. Borbor-Cordova, Washington B. Cárdenas, Cinthya Cueva, Julia L. Finkelstein, Christina D. Lupone, Richard G. Jarman, Irina Maljkovic Berry, Saurabh Mehta, Mark Polhemus, Mercy Silva and Timothy P. EndyAbstract.Here, we report the findings from the first 2 years (2014–2015) of an arbovirus surveillance study conducted in Machala, Ecuador, a dengue-endemic region. Patients with suspected dengue virus (DENV) infections (index cases, N = 324) were referred from five Ministry of Health clinical sites. A subset of DENV-positive index cases (N = 44) were selected, and individuals from the index household and four neighboring homes within 200 m were recruited (N = 400). Individuals who entered the study, other than the index cases, are referred to as associates. In 2014, 70.9% of index cases and 35.6% of associates had acute or recent DENV infections. In 2015, 28.3% of index cases and 12.8% of associates had acute or recent DENV infections. For every DENV infection captured by passive surveillance, we detected an additional three acute or recent DENV infections in associates. Of associates with acute DENV infections, 68% reported dengue-like symptoms, with the highest prevalence of symptomatic acute infections in children aged less than 10 years. The first chikungunya virus (CHIKV) infections were detected on epidemiological week 12 in 2015; 43.1% of index cases and 3.5% of associates had acute CHIKV infections. No Zika virus infections were detected. Phylogenetic analyses of isolates of DENV from 2014 revealed genetic relatedness and shared ancestry of DENV1, DENV2, and DENV4 genomes from Ecuador with those from Venezuela and Colombia, indicating the presence of viral flow between Ecuador and surrounding countries. Enhanced surveillance studies, such as this, provide high-resolution data on symptomatic and inapparent infections across the population.
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Dengue Virus Infection in Aedes albopictus during the 2014 Autochthonous Dengue Outbreak in Tokyo Metropolis, Japan
Abstract.In 2014 in Japan, 162 autochthonous dengue cases were reported for the first time in nearly 70 years. Here, we report the results of the detection and isolation of dengue virus (DENV) from mosquitoes collected in Tokyo Metropolis in 2014 and 2015. The phylogenetic relationship among DENV isolates from mosquitoes and from patients based on both the entire envelope gene and whole coding sequences was evaluated. Herein, 2,298 female and 956 male Aedes albopictus mosquitoes were collected at six suspected locations of DENV infection in Tokyo Metropolis from August to October in 2014 and grouped into 124 and 35 pools, respectively, for viral genome detection and DENV isolation. Dengue virus RNA was detected using reverse transcription polymerase chain reaction and TaqMan assays from 49 female pools; 16 isolates were obtained using C6/36 and Vero cells. High minimum infection rates (11.2–66.7) persisted until mid-September. All DENV isolates belonged to the genotype I in serotype 1 (DENV-1), and its sequences demonstrated > 99% homology to the sequence of the DENV isolated from a patient in the vicinity of Tokyo Metropolis in 2014. Therefore, Ae. albopictus was a major DENV vector, and a single DENV-1 strain circulated in Tokyo Metropolis in 2014. Dengue virus was not detected from male mosquitoes in 2014 and wild larvae in April 2015. Thus, the possibility of both vertical transmission and overwintering of DENV was extremely low, even in dengue-epidemic areas. This study reports the first entomological information on a dengue outbreak in a temperate region, where no Aedes aegypti mosquitoes are distributed.
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Dengue Fever as an Emerging Infection in Southeast Iran
Abstract.Dengue fever (DF) is a mosquito-borne acute viral disease presenting with hemorrhagic manifestations in severe cases. Southeast Iran is in close proximity to Pakistan, an endemic country for DF. This cross-sectional study was conducted in the Sistan and Baluchestan province in the southeast of Iran to investigate possibility of DF (immunoglobulin M [IgM], immunoglobulin G [IgG], and nonstructural protein 1 [NS1] antigen tests) in 60 clinically suspected patients (April 2013 to August 2015). NS1 protein was detected in 5% (N = 3), at least one of the antibodies (IgM and/ or IgG) was detected in 11% (N = 7) of the samples. Five patients identified as of acutely infected. There was a simultaneous presence of NS1 protein and IgG or IgM antibodies in 4% (N = 2) of patients. Previous studies show establishment of potential vectors in this area. These evidences support the hypothesis that DF can be a health concern in Southeast Iran with potential future outbreaks.
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Eastern Equine Encephalitis Virus in the United States, 2003–2016
More LessAbstract.Eastern equine encephalitis virus (EEEV) is a mosquito-borne alphavirus found in the eastern United States. Eastern equine encephalitis virus disease in humans is rare but can result in severe, often fatal, illness. This report summarizes the national EEEV surveillance data for 2003 through 2016, including human disease cases and nonhuman infections. Over the 14-year period, 633 counties from 33 states reported EEEV activity; 88% of those counties reported EEEV activity only in nonhuman species. A total of 121 human cases of EEEV disease were reported, with a median of eight cases reported annually. The national average annual incidence of EEEV neuroinvasive disease was 0.03 cases per million population. States with the highest average annual incidence included New Hampshire, Massachusetts, Vermont, Maine, and Alabama. Eastern equine encephalitis virus neuroinvasive disease incidence was highest among males and among persons aged < 5 and > 60 years. Overall, 118 (98%) case patients were hospitalized and 50 (41%) died. The case fatality ratio was highest among case patients aged ≥ 70 years. Nonhuman surveillance data indicate that the geographic range of EEEV is much greater than human cases alone might suggest. In areas where the virus circulates, health-care providers should consider EEEV infection in the differential diagnosis for meningitis and encephalitis. Providers are encouraged to report suspected cases to their public health department to facilitate diagnosis and consider interventions to mitigate the risk of further transmission. Because human vaccines against EEEV are not available, prevention depends on community efforts to reduce mosquito populations and personal protective measures to decrease exposure to mosquitoes.
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Association between Severe Fever with Thrombocytopenia Syndrome Incidence and Ambient Temperature
More LessAbstract.Severe fever with thrombocytopenia syndrome (SFTS) is emerging in China. To explore the lagged effects and nonlinear association between temperature and SFTS, we collected data on ambient temperature and SFTS cases and analyzed the data using a distributed lag nonlinear model. A total of 1,933 SFTS cases were reported in the study area from 2011 to 2015. Our study revealed a nonlinear relationship between weekly temperature and SFTS. The exposure–response curve was an approximately reversed U-shaped peak at 23°C. High temperatures had acute and short-term effects, whereas low temperatures had persistent and long-term effects. The effects of lower temperatures (1.62°C and 6.97°C) could last 24 weeks, but the effect of 29.30°C was not significant at lag 8 weeks. Our results provide information to better understand the effect of temperature variation on SFTS and may have policy implications for disease prevention and control.
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Food Insecurity as a Risk Factor for Outcomes Related to Ebola Virus Disease in Kono District, Sierra Leone: A Cross-Sectional Study
Abstract.Studies have shown that people suffering from food insecurity are at higher risk for infectious and noncommunicable diseases and have poorer health outcomes. No study, however, has examined the association between food insecurity and outcomes related to Ebola virus disease (EVD). We conducted a cross-sectional study in two Ebola-affected communities in Kono district, Sierra Leone, from November 2015 to September 2016. We enrolled persons who were determined to have been exposed to Ebola virus. We assessed the association of food insecurity, using an adapted version of the Household Food Insecurity Access Scale, a nine-item scale well validated across Africa, with having been diagnosed with EVD and having died of EVD, using logistic regression models with cluster-adjusted standard errors. We interviewed 326 persons who were exposed to Ebola virus; 61 (19%) were diagnosed with EVD and 45/61 (74%) died. We found high levels (87%) of food insecurity, but there was no association between food insecurity and having been diagnosed with EVD. Among EVD cases, those who were food insecure had 18.3 times the adjusted odds of death than those who were food secure (P = 0.03). This is the first study to demonstrate a potential relationship between food insecurity and having died of EVD, although larger prospective studies are needed to confirm these findings.
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Challenges and Opportunities in Disease Forecasting in Outbreak Settings: A Case Study of Measles in Lola Prefecture, Guinea
Abstract.We report on and evaluate the process and findings of a real-time modeling exercise in response to an outbreak of measles in Lola prefecture, Guinea, in early 2015 in the wake of the Ebola crisis. Multiple statistical methods for the estimation of the size of the susceptible (i.e., unvaccinated) population were applied to weekly reported measles case data on seven subprefectures throughout Lola. Stochastic compartmental models were used to project future measles incidence in each subprefecture in both an initial and a follow-up iteration of forecasting. Measles susceptibility among 1- to 5-year-olds was estimated to be between 24% and 43% at the beginning of the outbreak. Based on this high baseline susceptibility, initial projections forecasted a large outbreak occurring over approximately 10 weeks and infecting 40 children per 1,000. Subsequent forecasts based on updated data mitigated this initial projection, but still predicted a significant outbreak. A catch-up vaccination campaign took place at the same time as this second forecast and measles cases quickly receded. Of note, case reports used to fit models changed significantly between forecast rounds. Model-based projections of both current population risk and future incidence can help in setting priorities and planning during an outbreak response. A swiftly changing situation on the ground, coupled with data uncertainties and the need to adjust standard analytical approaches to deal with sparse data, presents significant challenges. Appropriate presentation of results as planning scenarios, as well as presentations of uncertainty and two-way communication, is essential to the effective use of modeling studies in outbreak response.
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Knowledge of Norovirus and Attitudes toward a Potential Norovirus Vaccine in Rural Guatemala: A Cross-Sectional Exploratory Survey
More LessAbstract.Given limited data on norovirus vaccine acceptance, we performed an exploratory survey in a rural Guatemalan community on knowledge, interest, and willingness to pay (WTP) for a norovirus vaccine. Cluster-randomized households with children aged 6 weeks to 17 years were enrolled into one of two norovirus surveillance studies: 1) a prospective cohort (N = 207 households) and 2) two separate, community-based, cross-sectional surveys (N = 420 households). After completion of the surveillance study, vaccine surveys were completed by 564 (90%) of 627 households. Most households correctly answered questions regarding norovirus symptoms and transmission; 97% indicated interest in a hypothetical norovirus vaccine. Households with higher education had greater WTP for a vaccine (prevalence ratios = 2.2, 95% confidence interval: 1.2–3.1) and households with lower WTP were more likely to use pharmacies, the Ministry of Health, and radios for health care and information. These results suggest that a future norovirus vaccination program could be acceptable and feasible even in rural areas.
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Characterization of the Gamboa Virus Serogroup (Orthobunyavirus Genus, Peribunyaviridae Family)
Jannifer Oliveira Chiang, William Marciel de Souza, Márcio Roberto Teixeira Nunes, Gustavo Olszanski Acrani, Amélia Paes de Andrade Travassos da Rosa, Nelma Mesquita de Freitas, Sandro Patroca da Silva, Pedro Henrique Dorta da Silva, Alana Watanabe de Sousa, Sueli Guerreiro Rodrigues, Juarez Antônio Simões Quaresma, Bedsy Dutary, Hilda Guzmán, Nikos Vasilakis, Robert B. Tesh and Pedro Fernando da Costa VasconcelosAbstract.Comprehensive comparative phylogenetic analyses were performed on 17 Gamboa serogroup viruses (GAMSVs) from distinct geographic regions in the Americas and other representative members of the genus Orthobunyavirus (Peribunyaviridae), based on small (S), medium (M), and large (L) open reading frame full-length and partial sequences. Genome characterization showed that the GAMSVs divide into four clades or genotypes. The GAMSVs have a genetic organization similar to other orthobunyaviruses, except that they have a larger NSm protein than other orthobunyaviruses. A serosurvey for Gamboa virus antibodies was performed in plasma from birds, other wild animals, and humans living around the Tucuruí hydroelectric dam in Pará state, northern Brazil, a known focus of GAMSV activity. Newborn chicks (Gallus gallus domesticus) were experimentally infected with a GAMSV, and the pathogenesis is described. Histopathological changes were primarily in the lungs and liver. Also, a review of the ecology of the GAMSVs in the Americas is included. In sum, this study presents the genomic and evolutionary characterization of the Gamboa group and the potential model of pathogenesis, which would be helpful for diagnostic purposes, epidemiology, and immunopathogenesis studies.
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Frequent Community Use of Antibiotics among a Low-Economic Status Population in Manila, the Philippines: A Prospective Assessment Using a Urine Antibiotic Bioassay
Abstract.The widespread unregulated use of antibiotics without medical consultation contributes to the burden of antibiotic resistance in Southeast Asian countries. This study investigated antibiotic use before hospital consultation. In a prospective observational study from February 2, 2015, to July 2, 2015, we enrolled febrile patients attending the emergency room in San Lazaro Hospital, Manila, the Philippines. A urine sample was collected and a bioassay was used to detect antibiotic activity in urine using Bacillus stearothermophilus (ATCC7953), Escherichia coli (ATCC25922), and Streptococcus pyogenes (ATCC19615). Patients or caregivers reported their medication history, clinical information, and socioeconomic status. During the study period, 410 patients were enrolled. The median (interquartile range) age was 14 (7–23) years and 158 (39%) reported prior antibiotic use, predominantly a beta-lactam antibiotic. A total of 164 (40%, 95% confidence interval [CI]: 35–45) patients were urine bioassay positive with any of three organisms. The Bacillus assay was the most sensitive, detecting 162 (99%, 95% CI: 96–100) cases. Among bioassay positive patients, dengue (N = 91, 55%, 95% CI: 48–63) was the most frequent diagnosis, followed by other viral infections, including measles, rubella, and mumps (N = 17, 10%, 95% CI: 6–16). Patients with a positive bioassay were significantly more likely to be from the lowest-income group (adjusted odds ratio [AOR]: 1.7; 95% CI: 1.1–2.6) and required hospital admission (AOR: 2.1; 95% CI: 1.3–3.5). Unnecessary antibiotic use for febrile illnesses before hospital consultation is common in a low-income, highly populated urban community in Manila. Education targeting this group should be implemented to reduce unnecessary antibiotic use.
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Antibiotic Residues in Milk from Three Popular Kenyan Milk Vending Machines
More LessAbstract.Milk vending machines (MVMs) are growing in popularity in Kenya and worldwide. Milk vending machines dispense varying quantities of locally sourced, pasteurized milk. The Kenya Dairy Board has a regulatory framework, but surveillance is weak because of several factors. Milk vending machines’ milk is not routinely screened for antibiotics, thereby increasing potential for antibiotic misuse. To investigate, a total of 80 milk samples from four commercial providers (N = 25), street vendors (N = 21), and three MVMs (N = 34) were collected and screened in Eldoret, Kenya. Antibiotic residue surveillance occurred during December 2016 and January 2017 using Idexx SNAP® tests for tetracyclines, sulfamethazine, beta-lactams, and gentamicin. Overall, 24% of MVM samples and 24% of street vendor samples were presumably positive for at least one antibiotic. No commercial samples were positive. Research into cost-effective screening methods and increased monitoring by food safety agencies are needed to uphold hazard analysis and critical control point for improving antibiotic stewardship throughout the Kenyan private dairy industry.
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Case Report: Paederus Dermatitis in the Returning Traveler
More LessAbstract.Rash in the returned traveler can provide a diagnostic dilemma for clinicians, but a detailed history including epidemiologic exposures can allow prompt diagnosis of etiologies uncommon in the United States. One such disease is Paederus dermatitis, an irritant contact dermatitis related to exposure to the rove beetle characterized by bullous lesions with surrounding erythema. Although cases and outbreaks have commonly been reported throughout the world, they are rarely reported in travelers returning to the United States. Here, we describe a patient who presented to an academic medical center in Virginia after travel to Sierra Leone with clinical presentation including exposure history and histopathology consistent with Paederus dermatitis. Our patient’s clinic course is described in detail including treatment. Usual treatment includes antihistamines, topical steroids, and oral antibiotics, particularly with antimicrobials with activity against Pseudomonas sp. In addition, this case suggests a potential role for oral steroids in the treatment of this condition but further investigation is required. This case demonstrates the importance of considering a patient’s travel and exposure history, as well as having familiarity with disease processes common in other parts of the world that are rarely seen in the United States.
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Vector-Borne Disease is a Common Cause of Hospitalized Febrile Illness in India
Matthew L. Robinson, Dileep Kadam, Sandhya Khadse, Usha Balasubramanian, Priyanka Raichur, Chhaya Valvi, Ivan Marbaniang, Savita Kanade, Jonathan Sachs, Anita Basavaraj, Renu Bharadwaj, Anju Kagal, Vandana Kulkarni, Jonathan Zenilman, George Nelson, Yukari C. Manabe, Aarti Kinikar, Amita Gupta and Vidya MaveAbstract.Acute febrile illness (AFI) is a major cause of morbidity and mortality in India and other resource-limited settings, yet systematic etiologic characterization of AFI has been limited. We prospectively enrolled adults (N = 970) and children (age 6 months to 12 years, N = 755) admitted with fever from the community to Sassoon General Hospital in Pune, India, from July 2013 to December 2015. We systematically obtained a standardized clinical history, basic laboratory testing, and microbiologic diagnostics on enrolled participants. Results from additional testing ordered by treating clinicians were also recorded. A microbiological diagnosis was found in 549 (32%) participants; 211 (12%) met standardized case definitions for pneumonia and meningitis without an identified organism; 559 (32%) were assigned a clinical diagnosis in the absence of a confirmed diagnosis; and 406 (24%) had no diagnosis. Vector-borne diseases were the most common cause of AFI in adults including dengue (N = 188, 19%), malaria (N = 74, 8%), chikungunya (N = 15, 2%), and concurrent mosquito-borne infections (N = 23, 2%) occurring most frequently in the 3 months after the monsoon. In children, pneumonia was the most common cause of AFI (N = 214, 28%) and death. Bacteremia was found in 68 (4%) participants. Central nervous system infections occurred in 58 (6%) adults and 64 (8%) children. Etiology of AFI in India is diverse, highly seasonal, and difficult to differentiate on clinical grounds alone. Diagnostic strategies adapted for season and age may reduce diagnostic uncertainty and identify causative organisms in treatable, fatal causes of AFI.
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Volumes & issues
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Volume 101 (2019)
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Volume 100 (2019)
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Volume 99 (2018)
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Volume 98 (2018)
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Volume 97 (2017)
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Volume 96 (2017)
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Volume 95 ([2016, 2017])
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Volume 94 (2016)
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Volume 93 (2015)
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Volume 92 (2015)
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Volume 91 (2014)
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Volume 90 (2014)
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Volume 89 (2013)
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Volume 88 (2013)
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Volume 87 (2012)
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Volume 86 (2012)
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Volume 85 (2011)
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Volume 84 (2011)
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Volume 83 (2010)
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Volume 82 (2010)
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Volume 81 (2009)
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Volume 80 (2009)
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Volume 79 (2008)
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Volume 78 (2008)
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Volume 77 (2007)
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Volume 76 (2007)
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Volume 75 (2006)
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Volume 74 (2006)
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Volume 73 (2005)
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Volume 72 (2005)
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Volume 71 (2004)
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Volume 70 (2004)
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Volume 69 (2003)
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Volume 68 (2003)
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Volume 67 (2002)
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Volume 66 (2002)
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Volume 65 (2001)
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Volume 64 (2001)
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Volume 63 (2000)
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Volume 62 (2000)
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Volume 61 (1999)
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Volume 60 (1999)
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Volume 59 (1998)
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Volume 58 (1998)
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Volume 57 (1997)
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Volume 56 (1997)
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Volume 55 (1996)
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Volume 54 (1996)
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Volume 53 (1995)
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Volume 52 (1995)
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Volume 51 (1994)
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Volume 50 (1994)
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Volume 49 (1993)
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Volume 48 (1993)
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Volume 47 (1992)
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Volume 46 (1992)
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Volume 45 (1991)
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Volume 44 (1991)
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Volume 43 (1990)
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Volume 42 (1990)
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Volume 41 (1989)
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Volume 40 (1989)
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Volume 39 (1988)
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Volume 38 (1988)
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Volume 37 (1987)
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Volume 36 (1987)
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Volume 35 (1986)
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Volume 34 (1985)
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Volume 33 (1984)
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Volume 32 (1983)
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Volume 31 (1982)
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Volume 30 (1981)
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Volume 29 (1980)
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Volume 28 (1979)
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Volume 27 (1978)
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Volume 26 (1977)
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Volume 25 (1976)
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Volume 24 (1975)
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Volume 23 (1974)
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Volume 22 (1973)
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Volume 21 (1972)
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Volume 20 (1971)
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Volume 19 (1970)
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Volume 18 (1969)
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Volume 17 (1968)
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Volume 16 (1967)
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Volume 15 (1966)
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Volume 14 (1965)
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Volume 13 (1964)
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Volume 12 (1963)
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Volume 11 (1962)
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Volume 10 (1961)
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Volume 9 (1960)
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Volume 8 (1959)
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Volume 7 (1958)
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Volume 6 (1957)
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Volume 5 (1956)
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Volume 4 (1955)
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Volume 3 (1954)
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Volume 2 (1953)
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Volume 1 (1952)
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Volume s1-31 (1951)
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Volume s1-30 (1950)
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Volume s1-29 (1949)
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Volume s1-28 (1948)
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Volume s1-27 (1947)
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Volume s1-26 (1946)
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Volume s1-25 (1945)
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Volume s1-24 (1944)
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Volume s1-23 (1943)
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Volume s1-22 (1942)
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Volume s1-21 (1941)
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Volume s1-20 (1940)
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Volume s1-19 (1939)
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Volume s1-18 (1938)
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Volume s1-17 (1937)
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Volume s1-16 (1936)
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Volume s1-15 (1935)
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Volume s1-14 (1934)
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Volume s1-13 (1933)
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Volume s1-12 (1932)
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Volume s1-11 (1931)
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Volume s1-10 (1930)
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Volume s1-9 (1929)
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Volume s1-8 (1928)
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Volume s1-7 (1927)
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Volume s1-6 (1926)
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Volume s1-5 (1925)
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Volume s1-4 (1924)
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Volume s1-3 (1923)
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Volume s1-2 (1922)
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Volume s1-1 (1921)