The American Journal of Tropical Medicine and Hygiene - Volume 88, Issue 4, April 2013

A Good Clinical Practices (GCPs) course, based on the combination of theoretical modules with a practical training in real-life conditions, was held in 2010 in Burkina Faso. It was attended by 15 trainees from nine African, Asian, and Latin American countries. There were some discrepancies between the average good results at the end of the theoretical phase and the GCP application during the first days of the practical phase, underlying the difficulties of translating theoretical knowledge into good practices. Most of the findings were not unexpected and reflected the challenges commonly faced by clinical investigators in resource-poor contexts (i.e., the high workload at peripheral health facilities, the need to conciliate routine clinical activities with clinical research, and the risk of creating a double standard among patients attending the same health facility [free care for recruited patients versus user fees for non-recruited patients with the same medical condition]). Even if limited in number and time, these observations suggest that a theoretical training alone may not be sufficient to prepare trainees for the challenges of medical research in real-life settings. Conversely, when a practical phase immediately follows a theoretical one, trainees can immediately experience what the research methodology implicates in terms of work organization and relationship with recruited and non-recruited patients. This initial experience shows the complexity of translating GCP into practice and suggests the need to rethink the current conception of GCP training.

The Laboratory Without Walls is a modular field application of molecular biology that provides clinical laboratory support in resource-limited, remote locations. The current repertoire arose from early attempts to deliver clinical pathology and public health investigative services in remote parts of tropical Australia, to address the shortcomings of conventional methods when faced with emerging infectious diseases. Advances in equipment platforms and reagent chemistry have enabling rapid progress, but also ensure the Laboratory Without Walls is subject to continual improvement. Although new molecular biology methods may lead to more easily deployable clinical laboratory capability, logistic and technical governance issues continue to act as important constraints on wider implementation.

Technologies to detect bed bugs have not kept pace with their global resurgence. Early detection is critical to prevent infestations from spreading. Detection based exclusively on bites is inadequate, because reactions to insect bites are non-specific and often misdiagnosed. Visual inspections are commonly used and depend on identifying live bugs, exuviae, or fecal droplets. Visual inspections are inexpensive, but they are time-consuming and unreliable when only a few bugs are present. Use of a dog to detect bed bugs is gaining in popularity, but it can be expensive, may unintentionally advertise a bed bug problem, and is not foolproof. Passive monitors mimic natural harborages; they are discreet and typically use an adhesive to trap bugs. Active monitors generate carbon dioxide, heat, a pheromone, or a combination to attract bed bugs to a trap. New technologies using DNA analysis, mass spectrometry, and electronic noses are innovative but impractical and expensive for widespread use.

We created a mobile phone microscope and assessed its accuracy for the diagnosis of soil-transmitted helminths compared with conventional microscopy. Mobile phone microscopy has a sensitivity of 69.4% for detecting any helminth egg and sensitivities of 81.0%, 54.4%, and 14.3% for the diagnosis of Ascaris lumbricoides, Trichuris trichiura and hookworm respectively.

In this study, we evaluate the effect of participatory Ecohealth interventions on domestic reinfestation of the Chagas disease vector Triatoma dimidiata after village-wide suppression of the vector population using a residual insecticide. The study was conducted in the rural community of La Brea, Guatemala between 2002 and 2009 where vector infestation was analyzed within a spatial data framework based on entomological and socio-economic surveys of homesteads within the village. Participatory interventions focused on community awareness and low-cost home improvements using local materials to limit areas of refuge and alternative blood meals for the vector within the home, and potential shelter for the vector outside the home. As a result, domestic infestation was maintained at ≤ 3% and peridomestic infestation at ≤ 2% for 5 years beyond the last insecticide spraying, in sharp contrast to the rapid reinfestation experienced in earlier insecticide only interventions.

A novel method using vector blood meal sources to assess the impact of control efforts on the risk of transmission of Chagas disease was tested in the village of El Tule, Jutiapa, Guatemala. Control used Ecohealth interventions, where villagers ameliorated the factors identified as most important for transmission. First, after an initial insecticide application, house walls were plastered. Later, bedroom floors were improved and domestic animals were moved outdoors. Only vector blood meal sources revealed the success of the first interventions: human blood meals declined from 38% to 3% after insecticide application and wall plastering. Following all interventions both vector blood meal sources and entomological indices revealed the reduction in transmission risk. These results indicate that vector blood meals may reveal effects of control efforts early on, effects that may not be apparent using traditional entomological indices, and provide further support for the Ecohealth approach to Chagas control in Guatemala.

In 2008–2009, Zimbabwe experienced an unprecedented cholera outbreak with more than 4,000 deaths. More than 60% of deaths occurred at the community level. We conducted descriptive and case–control studies to describe community deaths. Cases were in cholera patients who died outside health facilities. Two surviving cholera patients were matched by age, time of symptom onset, and location to each case-patient. Proxies completed questionnaires regarding mortality risk factors. Cholera awareness and importance of rehydration was high but availability of oral rehydration salts was low. A total of 55 case-patients were matched to 110 controls. The odds of death were higher among males (adjusted odd ratio [AOR] = 5.00, 95% confidence interval [CI] = 1.54–14.30) and persons with larger household sizes (AOR = 1.21, 95% CI = 1.00–1.46). Receiving home-based rehydration (AOR = 0.21, 95% CI = 0.06–0.71) and visiting cholera treatment centers (CTCs) (AOR = 0.07, 95% CI = 0.02–0.23) were protective. Receiving cholera information was associated with home-based rehydration and visiting CTCs. When we compared cases and controls who did not go to CTCs, males were still at increased odds of death (AOR = 5.00, 95% CI = 1.56–16.10) and receiving home-based rehydration (AOR = 0.14, 95% CI = 0.04–0.53) and being married (AOR = 0.26, 95% CI = 0.08–0.83) were protective. Inability to receive home-based rehydration or visit CTCs was associated with mortality. Community education must reinforce the importance of prompt rehydration and CTC referral.

Innovative solutions are essential to improving global access to potable water for nearly 1 billion people. This study presents an independent investigation of one alternative by examining for-profit water-vending kiosks, WaterHealth Centers (WHCs), in rural Ghana to determine their association with household drinking water quality. WHCs' design includes surface water treatment using filtration and ultraviolet light disinfection along with community-based hygiene education. Analyses of water samples for Escherichia coli and household surveys from 49 households across five villages collected one time per year for 3 years indicate that households using WHCs had improved water quality compared with households using untreated surface water (adjusted incidence rate ratio = 0.07, 95% confidence interval = 0.02, 0.21). However, only 38% of households used WHCs by the third year, and 60% of those households had E. coli in their water. Recontamination during water transport and storage is an obstacle to maintaining WHC-vended water quality.

Data on non-typhoidal Salmonella (NTS) infection in South Asia are limited. We used data gathered prospectively from 1996 to 2011 as part of a hospital surveillance system in Dhaka, Bangladesh, to identify diarrheal patients with NTS isolated from stool. NTS was isolated in 1.3% (468 of 37,439) of diarrheal patients; 47% of total cases of NTS were in children < 5 years of age, although older adults (≥ 60 years) had the highest isolation rates. NTS isolation peaked in the monsoon months of July and August. Over the study period, rates of multidrug resistance decreased, whereas rates of decreased susceptibility to ciprofloxacin increased. Compared with control patients, NTS patients were older and wealthier; however, no differences in type of housing or exposure to animals were found. NTS patients had increased inflammatory cells in stool and required more fluid resuscitation.

Although increases in severity of mortality from dengue infection have been observed in Brazil, their determinants are not fully known. A case–control study was conducted by using the National Notifiable Diseases Surveillance System, including patients with severe dengue during 2000–2005. Cases were defined as patients that died and controls were those who survived. Hierarchical multivariate logistic regression was performed. During the study period, there were 12,321 severe cases of dengue and 1,062 deaths. Factors independently associated with death included age ≥ 50 years (odds ratio [OR] = 2.29, 95% confidence interval [CI] = 1.59–3.29), < 4 years of schooling (OR = 1.83, 95% CI = 1.47–2.28), a rural area (OR =2.84, 95% CI = 2.19–3.69), hospitalization (OR = 1.42, 95% CI = 1.17–1.73), and a high hematocrit (OR = 2.46, 95% CI = 1.85–3.28). Factors associated with a lower chance of dying were female sex (OR = 0.76, 95% CI = 0.67–0.87), history of previous dengue (OR = 0.78, 95% CI = 0.62–0.99), positive tourniquet test result (OR = 0.47, 95% CI = 0.33–0.66), laboratory diagnosis of dengue (OR = 0.75, 95% CI = 0.61–0.92), and a platelet count of 50,000–100,000 cells/mm3 (OR = 0.56, 95% CI = 0.36–0.87). The risk profile identified in this study should serve to direct public health interventions to minimize deaths.

We report on the changing epidemiology of two important flaviviruses in Nepal: Japanese encephalitis (JE) and dengue viruses. Morbidity and mortality in Nepal is in the thousands since JE was introduced in 1978. Nepal launched an extensive laboratory-based JE surveillance in 2004. Nepal experienced a remarkable reduction in disease burden after mass immunizations from 2005 to 2010, when 2,040 JE infections and 205 JE-related deaths were confirmed. With its emergence in 2006, dengue has become a significant challenge in the country, highlighted by a sudden outbreak in 2010 that resulted in 359 confirmed dengue infections. Currently, both viruses cocirculate in Nepal. Here, we document the remarkable expansion of dengue in Nepal, which urgently requires national surveillance to refine the burden and make recommendations regarding control and prevention programs. We believe that the use of existing JE surveillance network for integrated dengue surveillance may represent the most appropriate alternative.

Japanese encephalitis virus (JEV) infection in mosquitoes was monitored in Vietnam from 2006 to 2008. A total of 15,225 mosquitoes, identified as 26 species in five genera were collected and 12,621 were grouped into 447 pools for examination of JEV infection by assays for cytopathic effects in C6/36 cells and by RT-PCR to detect flavivirus RNA. Three JEV strains were isolated from Culex tritaeniorhynchus Giles collected in northern and southern Vietnam and two JEV strains were isolated from Culex vishnui Theobald collected in the highlands of Vietnam. Genetic and phylogenetic analyses, based on complete E gene nucleotide sequences, revealed that the five JEV strains were classified into the genotype I group and six amino acid differences were found in these five strains. These results indicated that multiple JEV genotype I populations are circulating countrywide in Vietnam, transmitted by bites of their Cx. tritaeniorhynchus and Cx. vishnui.

Diurnal temperature fluctuations can fundamentally alter mosquito biology and mosquito-virus interactions in ways that impact pathogen transmission. We investigated the effect of two daily fluctuating temperature profiles on Aedes aegypti vector competence for dengue virus (DENV) serotype-1. A large diurnal temperature range of 18.6°C around a 26°C mean, corresponding with the low DENV transmission season in northwestern Thailand, reduced midgut infection rates and tended to extend the virus extrinsic incubation period. Dissemination was first observed at day 7 under small fluctuations (7.6°C; corresponding with high DENV transmission) and constant control temperature, but not until Day 11 for the large diurnal temperature range. Results indicate that female Ae. aegypti in northwest Thailand are less likely to transmit DENV during the low than high transmission season because of reduced DENV susceptibility and extended virus extrinsic incubation period. Better understanding of DENV transmission dynamics will come with improved knowledge of temperature effects on mosquito-virus interactions.

In a previous study conducted in Cyprus, various spotted fever group Rickettsia species were detected and identified in ticks by molecular analysis. Among them, a partially characterized Rickettsia species was detected in Hyalomma anatolicum excavatum and Rhipicephalus turanicus ticks. We report characterization of this rickettsial strain by using polymerase chain reaction sequencing analysis of partial citrate synthase A, outer membrane protein A, outer membrane protein B, and 17-kD protein genes. We propose a provisional name Rickettsia sp. strain Tselenti for this strain until it is isolated and further characterized.

Rats are considered the principal maintenance hosts of Leptospira. The objectives of this study were isolation and identification of Leptospira serovars circulating among urban rat populations in Kuala Lumpur. Three hundred urban rats (73% Rattus rattus and 27% R. norvegicus) from three different sites were trapped. Twenty cultures were positive for Leptospira using dark-field microscopy. R. rattus was the dominant carrier (70%). Polymerase chain reaction (PCR) confirmed that all isolates were pathogenic Leptospira species. Two Leptospira serogroups, Javanica and Bataviae, were identified using microscopic agglutination test (MAT). Pulsed-field gel electrophoresis (PFGE) identified two serovars in the urban rat populations: L. borgpetersenii serovar Javanica (85%) and L. interrogans serovar Bataviae (15%). We conclude that these two serovars are the major serovars circulating among the urban rat populations in Kuala Lumpur. Despite the low infection rate reported, the high pathogenicity of these serovars raises concern of public health risks caused by rodent transmission of leptospirosis.

In 2007, the first free mass distribution of insecticide-treated bed nets (ITNs) occurred in southern Zambia. To determine the effect of ITNs on heterogeneity in biting rates, human DNA from Anopheles arabiensis blood meals was genotyped to determine the number of hosts that had contributed to the blood meals. The multiple feeding rate decreased from 18.9% pre-ITN to 9.1% post-ITN, suggesting that mosquito biting had focused onto a smaller fraction of the population. Pre-ITN, 20% of persons in a household provided 40% of blood meals, which increased to 59% post-ITN. To measure heterogeneity over a larger scale, mosquitoes were collected in 90 households in two village areas. Of these households, 25% contributed 78.1% of An. arabiensis, and households with high frequencies of An. arabiensis were significantly spatially clustered. The results indicate that substantial heterogeneity in malaria risk exists at local and household levels, and household-level heterogeneity may be influenced by interventions, such as ITNs.

High levels of genetic diversity in Plasmodium falciparum populations are an obstacle to malaria control. Here, we investigate the relationship between local variation in malaria epidemiology and parasite genetic diversity in Papua New Guinea (PNG). Cross-sectional malaria surveys were performed in 14 villages spanning four distinct malaria-endemic areas on the north coast, including one area that was sampled during the dry season. High-resolution msp2 genotyping of 2,147 blood samples identified 761 P. falciparum infections containing a total of 1,392 clones whose genotypes were used to measure genetic diversity. Considerable variability in infection prevalence and mean multiplicity of infection was observed at all of the study sites, with the area sampled during the dry season showing particularly striking local variability. Genetic diversity was strongly associated with multiplicity of infection but not with infection prevalence. In highly endemic areas, differences in infection prevalence may not translate into a decrease in parasite population diversity.

The St. Elizabeth strain of Plasmodium vivax originated in the South Carolina State Hospital instead of the St. Elizabeth Hospital in Washington, DC.