BackgroundInformation related to malaria vectors is very limited in Bangladesh. In the changing environment and various Anopheles 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.MethodsAnopheles 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 Plasmodium falciparum, Plasmodium vivax-210 and Plasmodium vivax-247 circumsporozoite proteins (CSP) from the collected female species.ResultsA total of 634 female Anopheles mosquitoes belonging to 17 species were collected. Anopheles vagus (was the dominant species (18.6%) followed by Anopheles nigerrimus (14.5%) and Anopheles philippinensis (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 P. falciparum, seven (1.1%) mosquitoes belonging to five species were positive for P. vivax -210 and a single mosquito (0.2%) identified as Anopheles maculatus was positive for P. vivax-247. No mixed infection was found. Highest infection rate was found in Anopheles karwari (22.2%) followed by An. maculatus (14.3%) and Anopheles barbirostris (9.5%). Other positive species were An. nigerrimus (4.4%), An. vagus (4.3%), Anopheles subpictus (1.5%) and An. philippinensis (1.4%). Anopheles vagus and An. philippinensis were previously incriminated as malaria vector in Bangladesh. In contrast, An. karwari, An. maculatus, An. barbirostris, An. nigerrimus and An. subpictus had never previously been incriminated in Bangladesh.ConclusionFindings of this study suggested that in absence of major malaria vectors there is a possibility that other Anopheles 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.

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BackgroundVisceral leishmaniasis (VL) remains as one of the most neglected tropical diseases with over 60% of the world’s total VL cases occurring in the Indian subcontinent. Due to the invasive risky procedure and technical expertise required in the classical parasitological diagnosis, the goal of the VL experts has been to develop noninvasive procedure(s) applicable in the field settings. Several serological and molecular biological approaches have been developed over the last decades, but only a few are applicable in field settings that can be performed with relative ease. Recently, loop-mediated isothermal amplification (LAMP) has emerged as a novel nucleic acid amplification method for diagnosis of VL. In this study, we have evaluated the LAMP assay using buffy coat DNA samples from VL patients in Bangladesh and compared its performance with leishmania nested PCR (Ln-PCR), an established molecular method with very high diagnostic indices.MethodsSeventy five (75) parasitologically confirmed VL patients by spleen smear microcopy and 101 controls (endemic healthy controls −25, non-endemic healthy control-26, Tuberculosis-25 and other diseases-25) were enrolled in this study. LAMP assay was carried out using a set of four primers targeting L. donovani kinetoplast minicircle DNA under isothermal (62 °C) conditions in a heat block. For Ln-PCR, we used primers targeting the parasite’s small-subunit rRNA region.ResultsLAMP assay was found to be positive in 68 of 75 confirmed VL cases, and revealed its diagnostic sensitivity of 90.7% (95.84-81.14, 95% CI), whereas all controls were negative by LAMP assay, indicating a specificity of 100% (100–95.43, 95% CI). The Ln-PCR yielded a sensitivity of 96% (98.96-87.97, 95% CI) and a specificity of 100% (100–95.43, 95% CI).ConclusionHigh diagnostic sensitivity and excellent specificity were observed in this first report of LAMP diagnostic evaluation from Bangladesh. Considering its many fold advantages over conventional PCR and potential to be used as a simple and rapid test in the VL endemic areas of the Indian subcontinent, our findings are encouraging, but further evaluation of LAMP is needed.

The incidence of PKDL is reducing in India after introduction of miltefosine and amphotericin B for treatment of visceral leishmaniasis. It remains higher in Bangladesh and in Sudan. Parasite burden is higher in nodular and papular forms of PKDL compared to the macular form of the disease. The demonstration of Leishmania DNA in peripheral blood buffy coat and in skin specimens can help to diagnose 40-75% clinically suspected PKDL individuals. An initial cure rate of 95% has been achieved with miltefosine for treatment of PKDL. However, the efficacy of combination therapy should be explored to reduce the treatment duration and hence to improve treatment compliance.