There are three main species of mosquitoes commonly found in Bangladesh – Culex, Aedes and Anopheles.
Culex is the most widespread. It can spread filariasis and Japanese encephalitis, although these diseases are not very prevalent in Bangladesh. Aedes mosquitoes spread dengue, while Anopheles mosquitoes are responsible for malaria.
Mohammad Shafiul Alam, a scientist at the International Center for Diarrheal Disease Research, Bangladesh (ICDDR,B), told Prothom Alo that the estimated mortality rate of Japanese encephalitis is 25 percent.
Although deaths have occurred in Rajshahi, Rangpur and hilly areas in the past, the disease is relatively uncommon in Bangladesh, partly because pig farming – an important transmission factor – is limited.
Researchers attribute the increase in mosquito populations to three main reasons: this winter was shorter than normal and ended earlier than normal, pollution in drains and water bodies has not been adequately controlled, and the absence of elected representatives in the two Dhaka city corporations has slowed down mosquito control programs.