COS 44-1
Seasonal abundance of Anopheles mosquitoes and their association with meteorological factors and malaria incidence in Bangladesh
The malaria situation in Bangladesh is complicated due to suitable environment, high species diversity and species complexes with many sibling species. The relationship between climatic factors and mosquito abundance is very important to determine parasite activity levels and disease risk. Therefore, this study was conducted to investigate the seasonal abundance of anophelines and their association with meteorological variables and disease transmission in two malaria endemic areas of Bangladesh during January, 2011 to January, 2012. Pearson correlation and canonical correspondence analyses (CCA) were computed to investigate the associations with species abundance and rainfall, temperature, humidity and malaria cases.
Results/Conclusions
A total of 2,443 female anophelines, representing 22 species were captured. Every female Anopheles were tested for P. falciparum, P. vivax 210 and P. vivax 247 CSP, of which 10 species were found positive. The CSP positive species were An. annularis, An. baimaii, An. barbirostris, An. jeyporiensis, An. karwari, An. minimus s.l., An. philippinensis, An. umbrosus, An. vagus and An. wilmori. Anopheles vagus and An. philippinensis were the dominant species present almost throughout the year with highest peaks in March and smallest peaks in September but An. baimaii and An. willmori were found during monsoon (July -September) only. Lag rainfall and relative humidity were the most significant variables influencing An. baimaii, An. willmori, An. vagus, and An. subpictus density in study area. Abundance of these four species positively related to malaria cases. The density of other Anopheles species negatively associated with rainfall, humidity. The effects of temperature were not found as a significant variable on the abundance of anophelines mosquitoes in Bangladesh. Our study demonstrates that the nature of relationship between malaria vector and climatic variables were multifaceted. Detailed studies of vector bionomics, continuous monitoring and malaria transmission dynamics is essential for predicting disease outbreaks and vector control in the region.