The American Journal of Tropical Medicine and Hygiene - Current Issue

Bancroftian filariasis can cause genital abnormalities related to chronic inflammation and obstruction of the afferent lymphatic vessels, and may demonstrate a “filarial dance sign” on scrotal ultrasound with mobile echogenic particles observed. We present a patient with a positive “filarial dance sign,” travel within Latin America, and negative filarial serology.

Lymphatic filariasis is a mosquito-borne parasitic infection caused by Wuchereria bancrofti and Brugia spp. Commonly seen in tropical developing countries, lymphatic filariasis occurs when adult worms deposit in and obstruct lymphatics. Although not endemic to the United States, a few cases of lymphatic filariasis caused by zoonotic Brugia spp. have been reported. Here we present a case of an 11-year-old female with no travel history who was seen in our clinic for a 1-year history of painless left cervical lymphadenopathy secondary to lymphatic filariasis. We review the literature of this infection and discuss the management of our patient. Using the National Inpatient Sample (NIS), the largest publicly available all-payer inpatient care database in the United States, we also examine the demographics of this infection. Our results show that chronic lymphadenopathy in the head and neck is the most common presenting symptoms of domestic lymphatic filariasis. Diagnosis is often made after surgical lymph node excision. Examination of the NIS from 2000 to 2014 revealed 865 patients admitted with a diagnosis of lymphatic filariasis. Most patients are in the mid to late sixties and are located on the eastern seaboard. Eight hundred and twenty six cases (95.5%) were likely due to zoonotic Brugia spp. and 39 (4.5%) due to W. bancrofti. Despite being rare, these data highlight the need to consider filariasis in patients presenting with chronic lymphadenopathy in the United States.

Loiasis is a vector-borne parasitic disease caused by the filarial nematode Loa loa and transmitted by the tabanid vectors from the genus Chrysops. Loa loa infection is associated with clinical manifestations such as pruritus, migratory transient edema, passage of adult worm in the bulbar conjunctiva, retinal damage, glomerular damage, albuminuria, pleural effusion, hydrocele, and endomyocardial fibrosis. Data reporting the occurrence of spontaneous encephalopathy associated with loiasis are very scanty. Severe adverse events occurring post-ivermectin administered in the framework of the fight against onchocerciasis and/or lymphatic filariasis in loiasis co-endemic areas have been closely associated with very high L. loa microfilariaemia. Different regimens have been used to lower L. loa microfilariaemia before definitive treatment, and many discrepancies have been reported. We report the case of a patient who was admitted to a health facility and hospitalized for 34 days for altered consciousness, blurred vision, headache, and chills. After other potential diagnoses were eliminated, the patient was confirmed with encephalopathy due to loiasis and referred to the Centre for Research on Filariasis and other Tropical Diseases (CRFilMT). On admission at CRFilMT, the patient was harboring 28,700 microfilariae per milliliter of blood (mf/mL), and after four 21-day courses of 400 mg daily albendazole, the L. loa microfilariaemia lowered to 5,060 mf/mL. The patient was then treated with ivermectin 3 mg and a total clearance of microfilariae was observed, with satisfactory clinical evolution and no adverse event. This case study further confirmed that albendazole is effective against L. loa, but might necessitate a longer course.

Ivermectin treatment can cause central nervous system adverse events (CNS-AEs) in persons with very high-density Loa loa microfilaremia (≥ 30,000 mf/mL blood). Hypoendemic onchocerciasis areas where L. loa is endemic have been excluded from ivermectin mass drug administration programs (MDA) because of the concern for CNS AEs. The rapid assessment procedure for L. loa (RAPLOA) is a questionnaire survey to assess history of eye worm. If ≥ 40% of respondents report eye worm, this correlates with ≥ 2% prevalence of very high-density loiasis microfilaremia, posing an unacceptable risk of CNS-AEs after MDA. In 2016, we conducted a L. loa study in 110 ivermectin-naïve, suspected onchocerciasis hypoendemic villages in southern Nigeria. In previous RAPLOA surveys these villages had prevalences between 10% and 67%. We examined 10,605 residents using the LoaScope, a cell phone–based imaging device for rapidly determining the microfilaria (mf) density of L. loa infections. The mean L. loa village mf prevalence was 6.3% (range 0–29%) and the mean individual mf count among positives was 326 mf/mL. The maximum individual mf count was only 11,429 mf/mL, and among 2,748 persons sampled from the 28 villages with ≥ 40% RAPLOA, the ≥ 2% threshold of very high Loa mf density could be excluded with high statistical confidence (P < 0.01). These findings indicate that ivermectin MDA can be delivered in this area with extremely low risk of L. loa–related CNS-AEs. We also concluded that in Nigeria the RAPLOA survey methodology is not predictive of ≥ 2% prevalence of very high-density L. loa microfilaremia.

Chromoblastomycosis is a worldwide chronic subcutaneous infection caused by dematiaceous fungi and clinically characterized by verrucous lesions. Herein, we report a rare case of chromoblastomycosis caused by Fonsecaea monophora in a 60-year-old male carpenter with a 40-year history of psoriasis from Shandong in northern China. A fungal infection coexisting with psoriasis presents a management dilemma. Our patient responded well to combined itraconazole and acitretin therapy and the lesions resolved completely after 1 month of treatment.

Leptospirosis is a potentially fatal emerging zoonosis with worldwide distribution and a broad range of clinical presentations and exposure risks. It typically affects vulnerable populations in (sub)tropical countries but is increasingly reported in travelers as well. Diagnostic methods are cumbersome and require further improvement. Here, we describe leptospirosis among travelers presenting to the GeoSentinel Global Surveillance Network. We performed a descriptive analysis of leptospirosis cases reported in GeoSentinel from January 1997 through December 2016. We included 180 travelers with leptospirosis (mostly male; 74%; mostly tourists; 81%). The most frequent region of infection was Southeast Asia (52%); the most common source countries were Thailand (N = 52), Costa Rica (N = 13), Indonesia, and Laos (N = 11 each). Fifty-nine percent were hospitalized; one fatality was reported. We also distributed a supplemental survey to GeoSentinel sites to assess clinical and diagnostic practices. Of 56 GeoSentinel sites, three-quarters responded to the survey. Leptospirosis was reported to have been most frequently considered in febrile travelers with hepatic and renal abnormalities and a history of freshwater exposure. Serology was the most commonly used diagnostic method, although convalescent samples were reported to have been collected infrequently. Within GeoSentinel, leptospirosis was diagnosed mostly among international tourists and caused serious illness. Clinical suspicion and diagnostic workup among surveyed GeoSentinel clinicians were mainly triggered by a classical presentation and exposure history, possibly resulting in underdiagnosis. Suboptimal usage of available diagnostic methods may have resulted in additional missed, or misdiagnosed, cases.

Spotted fever group rickettsioses (SFGRs), such as African tick bite fever (ATBF), are among the most commonly diagnosed diseases for ill travelers returning from southern Africa. We summarized demographic, clinical, and diagnostic features of imported SFGR cases in U.S. travelers returning from Africa who had laboratory specimens submitted to the Centers for Disease Control and Prevention. Diagnosis of SFGR was performed by indirect immunofluorescence antibody assay, immunohistochemical staining, polymerase chain reaction (PCR), or culture. Cases were defined as probable SFGR, confirmed SFGR, or confirmed ATBF. Clinical and epidemiological categorical variables were described as counts and proportions; continuous variables were described using geometric mean titers, median, and range. One hundred and twenty-seven patients satisfied laboratory criteria for confirmed or probable SFGR. Fever was the most common symptom (N = 88; 69%), followed by ≥ 1 eschars (N = 70; 55%). Paired serums were submitted for 36 patients (28%); 12 patients (33%) had nonreactive initial serum sample but converted to a titer ≥ 64 with the convalescent sample. Twenty-seven patients (21%) had infection with Rickettsia africae based on PCR analysis of eschar swab (N = 8) or biopsy (N = 23). Fifteen patients had eschar biopsy or swab samples and serum sample(s) submitted together; 9 (60%) had PCR-positive eschar results and nonreactive acute serology. Health-care providers should consider SFGR when evaluating patients for a febrile illness with eschar and compatible foreign travel history. Polymerase chain reaction testing of eschar biopsies or swabs provides a confirmed diagnosis in early stages of disease; eschar swabs or biopsies are an underutilized diagnostic technique.

Delay in diagnosis and treatment worsens the disease and clinical outcomes, which further enhances transmission of tuberculosis (TB) in the community. Therefore, this study aims to assess treatment delay and its associated factors among pulmonary TB patients in Pakistan. A cross-sectional study was conducted among 269 pulmonary TB patients in the district. Binary and multivariate logistic regressions were used to explore the factors associated with delay in TB treatment. Results reveal that most patients were from low socioeconomic backgrounds. For example, 74.7% were living in kacha houses, 54.7% were from lowest the income group (< 250 US$/month), 60.2% married, 54.3% illiterate, 62.5% rural, 56.1% had no house ownership, and 56.5% had insufficient income for daily family expenditures. Significant delays were revealed by this study: 160 patients had experienced a delay of more than 4 weeks, whereas the median delay was 5 weeks. Results show that the most important reason for patient delay was low income and poverty (42.0%) followed by unaware of TB center (41.6), stigma (felt ashamed = 38.7%), and treatment from local traditional healers. Old age (adjusted odds ratio [AOR] = 6.6; 95% confidence interval [CI] = 1.63–26.95); and rural areas patients (AOR = 2.1; 95% CI = 1.15–3.71) were more likely to have experienced delay. However, the higher income and sufficient income category (AOR = 0.5; 95% CI = 0.31–0.95) were associated factors and less likely to experience delay in patient treatment. Integrative prevention interventions, such as those involving community leaders, health extension workers such as lady health workers, and specialized TB centers, would help to reduce delay and expand access to TB-care facilities.

Trachoma surveillance is typically performed via random sampling of endemic districts. This strategy minimizes bias and allows examination of preschool children, but is also expensive. Surveillance for some other neglected tropical diseases is carried out in schools, which is logistically easier. In the present study, the prevalence of trachomatous inflammation–follicular (TF) from a population-based sample of children from each of 70 communities in Ethiopia was compared with the corresponding school-based estimate, which was calculated for each community by performing examinations in all primary schools in the district. The overall prevalence of TF was 39.1% (95% confidence interval [CI]: 35.0–43.1%) among children aged 1–9 years in the community-based sample and 18.8% (95% CI: 15.9–21.7%) among children in grades 1–3 of the school-based sample. School-based estimates of TF explained 35% of the variation in the community-based prevalences (P < 0.001). When TF prevalence was used as a diagnostic test for detecting a community with > 5% prevalence of ocular chlamydia, the area under the receiver operating characteristic curve was 0.73 (95% CI: 0.60–0.85) for the school-based sample and 0.71 (0.58–0.83) for the community-based sample (P = 0.76). Thus, although school-based monitoring was necessarily biased relative to population-based monitoring of 1- to 9-year olds, the two methods provided a similar amount of information about the community burden of ocular chlamydia in this trachoma-hyperendemic setting. The generalizability of these findings to areas with less prevalent trachoma is unclear.

Staphylococcus aureus is a common cause of bloodstream infection and methicillin-resistant S. aureus (MRSA) is a growing threat worldwide. We evaluated the incidence rate of S. aureus bacteremia (SAB) and MRSA from population-based surveillance in all hospitals from two Thai provinces. Infections were classified as community-onset (CO) when blood cultures were obtained ≤ 2 days after hospital admission and as hospital-onset (HO) thereafter. The incidence rate of HO-SAB could only be calculated for 2009–2014 when hospitalization denominator data were available. Among 147,524 blood cultures, 919 SAB cases were identified. Community-onset S. aureus bacteremia incidence rate doubled from 4.4 (95% confidence interval [CI]: 3.3–5.8) in 2006 to 9.3 per 100,000 persons per year (95% CI: 7.6–11.2) in 2014. The highest CO-SAB incidence rate was among adults aged 50 years and older. Children less than 5 years old had the next highest incidence rate, with most cases occurring among neonates. During 2009–2014, there were 89 HO-SAB cases at a rate of 0.13 per 1,000 hospitalizations per year (95% CI: 0.10–0.16). Overall, MRSA prevalence among SAB cases was 10% (90/911) and constituted 7% (55/736) of CO-SAB and 20% (22/111) of HO-SAB without a clear temporal trend in incidence rate. In conclusion, CO-SAB incidence rate has increased, whereas MRSA incidence rate remained stable. The increasing CO-SAB incidence rate, especially the burden on older adults and neonates, underscores the importance of strong SAB surveillance to identify and respond to changes in bacteremia trends and antimicrobial resistance.

Chromobacterium violaceum is a rare, potentially serious pathogen. Most clinicians have no experience with its clinical appearance or treatment. We describe a case of a child presenting with necrotizing pneumonia caused by C. violaceum. We describe case complexities, including the need for a multidisciplinary approach to diagnosis and treatment.

Three cases of cholera occurred in South Korea during a period of three weeks in August 2016. All the cases were associated with the consumption of raw seafood in southern coastal area of South Korea. Epidemiologic investigations were performed to track the spread of cholera, including persons in contact with the cholera patients, seafood, and seawater from the fish tank and marine environments. A microbiological investigation demonstrated that cholera isolated from the three patients and a seawater sample at the Korea Strait showed identical serotype (O1 Ogawa), biotype (El tor), and toxin (ctx-positive). Pulsed-field gel electrophoresis analysis showed that the three clinical strains are identical (100%) and shared 97% identity with the seawater sample.

Diarrhea remains a leading cause of morbidity and mortality in patients worldwide. The objective of this study was to determine the relative inter-rater reliability and usability of standard and Mobile health (mHealth)-supported World Health Organization (WHO) algorithms for dehydration assessment in patients with acute diarrhea in a rural, low-income country hospital. Two nurses blinded to each other’s examinations assessed dehydration status on patients soon after hospital arrival using either the standard WHO algorithm printed on a laminated card or an mHealth-supported WHO algorithm downloaded onto a smartphone. The assignment of assessment tool was based on odd or even enrollment date. The inter-rater reliability for dehydration assessment between the two nurses was calculated using Cohen’s K statistic for each study group. A total of 496 patients (< 5 years N = 349, > 5 years N = 147) were enrolled in the study; 132 (27%) had some or severe dehydration, and 364 (73%) had no dehydration on arrival. Cohen’s K statistic demonstrated greater reliability for the mHealth-supported dehydration assessment (0.59) compared with the standard assessment (0.50) in the overall population (P < 0.0001), as well as in the pediatric (0.43 versus 0.37, P < 0.0001) and adult (0.79 versus 0.57, P < 0.0001) populations individually. This is the first study to show that mHealth can improve the reliability of nursing dehydration assessment in patients with acute diarrhea and the first to report on the reliability of the WHO algorithm in adult patients specifically. Future studies should focus on the impact of mHealth-supported dehydration assessment on patient-centered outcomes and examine its reliability in different settings worldwide.

Tick-borne encephalitis (TBE) is widely prevalent on the Eurasian continent, including Japan, but four cases of TBE have been reported in Japan. To inspect unconfirmed TBE cases in Japan, we conducted a retrospective seroepidemiological study of a total of 158 samples from 81 meningoencephalitis patients suspected as Lyme disease. Two serum samples from one patient showed neutralizing antibodies against TBE virus. The patient with severe and progressive encephalitis had a history of tick bite in Hokkaido in 2012. These results demonstrated that tick-borne encephalitis virus (TBEV) case was actually unconfirmed in Japan. Further seroepidemiological surveys are required to identify unconfirmed TBEV infections to consider the pros and cons of introducing specific countermeasures including vaccination in Japan.

Chronic stage chikungunya (CHIK), defined by persisting symptoms more than 3 months after initial diagnosis of acute infection, is frequent. However, its burden and impact have rarely been described prospectively in a general population during an ongoing epidemic in the Caribbean. From January 2014 to January 2015, a severe CHIK outbreak occurred in Martinique. Our objective was to describe epidemiological characteristics and outcomes of chronic stage CHIK in its local population. Participants, clinically diagnosed with probable CHIK infection, were included prospectively by general practitioners during the epidemic’s peak from April to October 2014. All identified cases benefited from a follow-up phone call 3 months or more after initial diagnosis during which they were interrogated about persisting clinical signs, past and ongoing treatment, and quality of life. Five hundred and nine subjects participated in the study. Mean age at initial diagnosis was 43.2 ± 23.6 years with a female–male ratio of 1.98. Two hundred participants (39.3%) had probable chronic stage CHIK: 98.5% still experienced pain at least 3 months after acute infection, with 84.3% of reported joint pains; 21.2% were woken up by the pain; 47.2% felt depressed/anxious; and 31.3% experienced memory/concentration disorders. Resumption of daily activity and work was complicated for 55.8% and 36.2% of cases. Persistent impact on morbidity, health outcomes, psychological, and economic aspects further underline the crucial role of community-based medicine and the necessity of an evidence-based multidisciplinary approach toward chronic stage CHIK identification, management, and follow-up in this particular world region.

A total of 1,090 residents of the city of Reynosa, Tamaulipas, on the Mexico–U.S. border presented at hospitals and clinics of the Secretariat of Health, Mexico, in 2015 with symptoms characteristic of dengue. Dengue virus (DENV) antigen was detected by enzyme-linked immunosorbent assay in acute sera from 134 (12.3%) patients. Sera from select patients (N = 34) were also tested for chikungunya virus (CHIKV) RNA by quantitative reverse transcription–polymerase chain reaction. Thirteen (38.2%) patients, including five DENV antigen-positive patients, were positive. Sera from three CHIKV RNA-positive patients were further assayed by virus isolation in cell culture and CHIKV was recovered on each occasion. The genome of one isolate and structural genes of the other two isolates were sequenced. In conclusion, we present evidence of CHIKV and DENV coinfections in patients who live near the Mexico–U.S. border and provide the first genome sequence of a CHIKV isolate from northern Mexico.

Dengue, a viral mosquito-borne disease currently affects more than 2.5 billion people living in endemic areas worldwide. In vector control, social mobilization and community behavioral changes are of crucial importance. Here, we identified the factors influencing community dengue preventive practices in a high-transmission urban area in Venezuela. Between September 2013 and February 2014, a cross-sectional study at the household level was carried out in Maracay city, Venezuela. A precoded questionnaire was used to obtain information on people’s knowledge, attitudes, and use of preventive practices in relation to dengue. Concomitantly, entomological data was collected from households. In 80% of the 105 included households, 1–5 preventive practices (e.g., repellents, insecticides) against mosquito bites were used. However, 57% of the examined houses had potential Aedes breeding sites indoors and/or outdoors, most of which positive for Aedes spp. larvae/pupae. Preventive practices were associated with a previous dengue infection (P = 0.030) and a better knowledge on dengue symptoms and transmission route (P = 0.020). In turn, knowledge was associated with feeling at risk (P < 0.001), a previous dengue infection (P = 0.010), and reported exposure to information sources of dengue (P = 0.011). Even though the knowledge level of the community over transmission ways was high, and most of the individuals took measures to avoid mosquito bites, potential mosquito breeding sites were present in almost two-thirds of the examined properties. Health promotion activities in Venezuela should aim at raising awareness at the community level on the importance of combining mosquito bite prevention with removal of breeding sites in and around the households.

Singapore has experienced periodic dengue epidemics despite maintaining a low Aedes house index. Each epidemic was associated with a switch in the predominant serotype. We investigated the temporal dynamics of dengue fever and dengue virus (DENV) and analyzed the epidemiological and entomological patterns of dengue in Singapore from 2004 to 2016. The case surveillance is based on a mandatory notification system that requires all medical practitioners to report clinically suspected and laboratory-confirmed cases. Circulating (DENV) serotypes are monitored through a virus surveillance program. Entomological surveillance involves inspections for larval breeding and monitoring of adults using gravitraps. Singapore experienced a similar epidemic pattern during 2004–2007 and 2013–2016. The pattern involved a 2-year DENV-1 epidemic occurring after a switch in the predominant serotype from DENV-2 to DENV-1, followed by a “lull” year. Thereafter, the predominant serotype switched back to DENV-2, tailed by a small-scale epidemic. Across the years, the highest incidence group was in the 25–44 years age group. The incidence rate of those aged ≥ 55 years was about half of that of the 15–24 years age group during DENV-1 predominant years. However, it was almost equal to the younger age group in DENV-2 predominant years. Types of Aedes aegypti breeding habitats remained similar. Dengue incidence was significantly higher in areas with high breeding percentage (BP) than areas with low BP (P < 0.05). In conclusion, the oscillation of DENV-1 and DENV-2, throughout the 13-year period, led to a cyclical epidemic pattern and older adults were more affected by DENV-2 than DENV-1.

Few studies have evaluated the effectiveness of Zika virus (ZIKV) public health educational campaigns. Following a ZIKV educational campaign in Roatán, Honduras (October 2016), a survey was administered (March–May 2017) to residents (N = 348) and health-care professionals ([HCPs]; N = 44) to evaluate ZIKV knowledge, attitudes, and preventive practices, with attention to sexual health. Knowledge scores were calculated and mapped using participants’ home locations. The knowledge scores between HCPs and residents were significantly different (mean 17 versus 11; P < 0.001). Only 6% of residents and 14% of HCPs knew that ZIKV was sexually transmissible. Few reported abstinence (2.6% residents; 9.4% HCPs) or condom use (1.6% residents; 12.5% HCPs) to prevent ZIKV infection. Of all subjects, 15.6% were pregnant or had a pregnant partner in the past year; 57.6% expressed concern over ZIKV. Mapping demonstrated spatial heterogeneity in knowledge. The findings suggest a need for improved public health messaging in ZIKV-affected areas.

St.Louis encephalitis virus (SLEV) is an emerging human pathogen flavivirus in Argentina. Recently, it has reemerged in the United States. We evaluated the role as amplifying host of six resident bird species and analyzed their capacity as host during the 2005 encephalitis outbreak of SLEV in Córdoba. Eared Dove, Picui Ground Dove, and House Sparrow were the three species with highest host competence index. At a city level, Eared Dove and Picui Ground Dove were the most important amplifying hosts during the 2005 SLEV human outbreak in Córdoba city. This finding highlighted important differences in the SLEV ecology between Argentina and the United States. Characterizing and evaluating the SLEV hosts contribute to our knowledge about its ecology and could help us to understand the causes that promote its emergence as a human pathogen in South America.