Vector-borne diseases

A vector is a transmitter of disease from one animal to another and to man. For many diseases, no effective immunizing agent is at present available and for others, specific chemotherapeutic agents do not exist or have serious disadvantages. In addition a number of the vectors have become resistant to pesticides used to kill them.

Most of the vector-borne disease are found in tropical areas of the world; however, some are distributed to the Arctic. The most important is malaria, of which there are an estimated 400 million cases. Other important disease are sleeping sickness, the vector is the tsetse fly; Chagas disease, the vector is a triatomid bug; onchocerciasis which is transmitted by a black fly of the Simulium damnosium complex; Bancroftian and Brugian Filariases which is transmitted by various mosquitoes; dengue and dengue haemorrhagic fever transmitted by a specific type of mosquito; yellow fever transmitted by a genus of mosquitoes; and schistosomiasis or bilharzia is transmitted by a small snail living in water.