Medical Importance of Mosquitoes

Mosquitoes are responsible for the transmission of many medically important pathogens and parasites such as viruses, bacteria, protozoans, and nematodes, which cause serious diseases such as malaria, dengue, yellow and Chikungunya fever, encephalitis or filariasis (Kettle 1995; Beaty and Marquardt 1996; Lehane 1991; Eldridge and Edman 2000). Transmission can be mechanical (e.g. Myxoma virus causing myxomatosis in rabbits) or biological. The latter is more complex because it involves an obligatory period of replication and/or development of the pathogen or parasite in the vector insect. Due to their blood-sucking behaviour, mosquitoes are able to acquire the pathogens or parasites from one vertebrate host and pass them to another, if the mosquito’s ecology and physiology is appropriate for transmission. Highly efficient vectors have to be closely associated with the hosts and their longevity has to be sufficient enough to enable the pathogens/parasites to proliferate and/or to develop to the infective stages in the vector. For successful transmission, multiple blood-meals are necessary.