Risk Factors for Kala-Azar in Bangladesh

Since 1990, South Asia has experienced a resurgence of kala-azar (visceral leishmaniasis). To determine risk factors for kala-azar, we performed cross-sectional surveys over a 3-year period in a Bangladeshi community. By history, active case detection, and serologic screening, 155 of 2,356 residents had kala-azar with onset from 2000 to 2003. Risk was highest for persons 3–45 years of age, and no significant difference by sex was seen. In age-adjusted multivariable models, 3 factors were identified: proximity to a previous kala-azar patient (odds ratio [OR] 25.4, 95% confidence interval [CI] 15–44 within household; OR 3.2 95% CI 1.7–6.1 within 50 m), bed net use in summer (OR 0.7, 95% CI 0.53–0.93), and cattle per 1,000 m2 (OR 0.8, 95% CI 0.70–0.94]). No difference was seen by income, education, or occupation; land ownership or other assets; housing materials and condition; or keeping goats or chickens inside bedrooms. Our data confirm strong clustering and suggest that insecticide-treated nets could be effective in preventing kala-azar

Prevalence of anopheline species and their Plasmodium infection status in epidemic-prone border areas of Bangladesh

<p>Abstract</p> <p>Background</p> <p>Information related to malaria vectors is very limited in Bangladesh. In the changing environment and various <it>Anopheles </it>species may be incriminated and play role in the transmission cycle. This study was designed with an intention to identify anopheline species and possible malaria vectors in the border belt areas, where the malaria is endemic in Bangladesh.</p> <p>Methods</p> <p><it>Anopheles </it>mosquitoes were collected from three border belt areas (Lengura, Deorgachh and Matiranga) during the peak malaria transmission season (May to August). Three different methods were used: human landing catches, resting collecting by mouth aspirator and CDC light traps. Enzyme-linked immunosorbent assay (ELISA) was done to detect <it>Plasmodium falciparum</it>, <it>Plasmodium vivax</it>-210 and <it>Plasmodium vivax</it>-247 circumsporozoite proteins (CSP) from the collected female species.</p> <p>Results</p> <p>A total of 634 female <it>Anopheles </it>mosquitoes belonging to 17 species were collected. <it>Anopheles vagus </it>(was the dominant species (18.6%) followed by <it>Anopheles nigerrimus </it>(14.5%) and <it>Anopheles philippinensis </it>(11.0%). Infection rate was found 2.6% within 622 mosquitoes tested with CSP-ELISA. Eight (1.3%) mosquitoes belonging to five species were positive for <it>P. falciparum</it>, seven (1.1%) mosquitoes belonging to five species were positive for <it>P. vivax </it>-210 and a single mosquito (0.2%) identified as <it>Anopheles maculatus </it>was positive for <it>P. vivax</it>-247. No mixed infection was found. Highest infection rate was found in <it>Anopheles karwari </it>(22.2%) followed by <it>An. maculatus </it>(14.3%) and <it>Anopheles barbirostris </it>(9.5%). Other positive species were <it>An. nigerrimus </it>(4.4%), <it>An. vagus </it>(4.3%), <it>Anopheles subpictus </it>(1.5%) and <it>An. philippinensis </it>(1.4%). <it>Anopheles vagus </it>and <it>An. philippinensis </it>were previously incriminated as malaria vector in Bangladesh. In contrast, <it>An. karwari</it>, <it>An. maculatus</it>, <it>An. barbirostris</it>, <it>An. nigerrimus </it>and <it>An. subpictus </it>had never previously been incriminated in Bangladesh.</p> <p>Conclusion</p> <p>Findings of this study suggested that in absence of major malaria vectors there is a possibility that other <it>Anopheles </it>species may have been playing role in malaria transmission in Bangladesh. Therefore, further studies are required with the positive mosquito species found in this study to investigate their possible role in malaria transmission in Bangladesh.</p

Malaria Vector Surveillance in Ganghwa-do, a Malaria-Endemic Area in the Republic of Korea

We investigated the seasonality of Anopheles mosquitoes, including its species composition, density, parity, and population densities of mosquitoes infected with the parasite in Ganghwa-do (Island), a vivax malaria endemic area in the Republic of Korea. Mosquitoes were collected periodically with a dry-ice-tent trap and a blacklight trap during the mosquito season (April-October) in 2008. Anopheles sinensis (94.9%) was the most abundant species collected, followed by Anopheles belenrae (3.8%), Anopheles pullus (1.2%), and Anopheles lesteri (0.1%). Hibernating Anopheles mosquitoes were also collected from December 2007 to March 2008. An. pullus (72.1%) was the most frequently collected, followed by An. sinensis (18.4%) and An. belenrae (9.5%). The composition of Anopheles species differed between the mosquito season and hibernation seasons. The parous rate fluctuated from 0% to 92.9%, and the highest rate was recorded on 10 September 2008. Sporozoite infections were detected by PCR in the head and thorax of female Anopheles mosquitoes. The annual sporozoite rate of mosquitoes was 0.11% (2 of 1,845 mosquitoes). The 2 mosquitoes that tested positive for sporozoites were An. sinensis. Malarial infections in anopheline mosquitoes from a population pool were also tried irrespective of the mosquito species. Nine of 2,331 pools of Anopheles mosquitoes were positive. From our study, it can be concluded that An. sinensis, which was the predominant vector species and confirmed as sporozoite-infected, plays an important role in malaria transmission in Ganghwa-do

An epidemiological overview of malaria in Bangladesh

Summary: Bangladesh is one of the four major malaria-endemic countries in South-East Asia having approximately 34% of its population at risk of malaria. This paper aims at providing an overview of the malaria situation in this country. Relevant information was retrieved from published articles and reports in PubMed and Google Scholar.Malaria in Bangladesh is concentrated in 13 districts with a prevalence ranging between 3.1% and 36%, and is mostly caused by Plasmodium falciparum. Geographical conditions pose a potential risk for Plasmodium knowlesi malaria. Resistance to a number of drugs previously recommended for treatment has been reported. Low socio-economic status, poor schooling and close proximity to water bodies and forest areas comprise important risk factors.Despite the significant steps in Long Lasting Insecticide Net (LLIN)/Insecticide Treated Net (ITN) coverage in Bangladesh, there are still many challenges including the extension of malaria support to the remote areas of Bangladesh, where malaria prevalence is higher, and further improvements in the field of referral system and treatmen