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

BACKGROUND: Information 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. METHODS: Anopheles 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. RESULTS: A 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. CONCLUSION: Findings 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.

Adherence and efficacy of supervised versus non-supervised treatment with artemether/lumefantrine for the treatment of uncomplicated Plasmodium falciparum malaria in Bangladesh: a randomised controlled trial.

As artemether/lumefantrine is now deployed as the first-line treatment for uncomplicated falciparum malaria in Bangladesh, information on its efficacy and adherence to its use is important. A randomised controlled non-inferiority trial comparing directly observed treatment (DOT) and non-directly observed treatment (NDOT) was conducted in 320 patients with uncomplicated falciparum malaria in Bandarban Hill Tract District, Bangladesh. Both regimens showed similar high levels of PCR-corrected 42-day parasitological and clinical cure rates (99.3% in the NDOT group and 100% in the DOT group; P=0.49). Survival analysis for the time to recurrence of infection showed no difference between treatment groups (log rank, P=0.98). Adherence, as assessed by counting remaining tablets and oral interviews, was 93% in the NDOT group and was confirmed by Day 7 lumefantrine concentrations. Adherence was independent of educational level. Patients with plasma lumefantrine concentrations < 280 ng/ml at Day 7 were at greater risk for re-infection (relative risk 5.62; P=0.027). The efficacy of artemether/lumefantrine for the treatment of uncomplicated falciparum malaria in Bangladesh is high and is similar for DOT and NDOT. Adherence to therapy is high.