Phlebotomine sandflies are small midge-like flies (approx 3 mm in length) which have a hairy appearance and conspicuous black eyes and stilt-like legs. Characteristically their wings are held erect over their body when at rest (in a ‘v’ shape). They have a short hopping flight with many landings.
The sub-family Phlebotominae includes numerous genera of blood-feeding flies including, most importantly, the vectors of leishmaniasis (a protozoan zoonotic disease, caused by more than 20 species of Leishmania parasite).
Leishmaniasis transmission occurs on every continent except Australia and Antarctica. In the Western Hemisphere, leishmaniasis is found in some parts of Mexico, Central America, and South America but it is not found in Chile or Uruguay. In the Eastern Hemisphere, leishmaniasis is found in parts of Asia, the Middle East, Africa, and southern Europe. The disease takes two forms – a lethal systemic disease (visceral leishmaniasis) and localised skin ulcers (cutaneous leishmaniasis).
- 90% of visceral leishmaniasis occurs in India, Bangladesh, Nepal, Sudan, Ethiopia and Brazil
- 90% of cutaneous leishmaniasis occurs in Afghanistan, Algeria, Iran, Saudi Arabia, Syria, Brazil, Colombia, Peru and Bolivia
- Female sandflies lay their eggs in moist soil, rich in organic matter. The time period from egg-laying to adult development is about 4 to 6 weeks. Given the very generalised type of breeding site the use of larvicides in sandfly control programmes is generally regarded as impractical. Current sandfly control practices rely on controlling the adults (e.g. residual spraying of dwellings and animal shelters, space spray application and insecticide-treated nets).
- It is important to note that in some parts of the world the term sandfly is used to describe biting midges (Ceratopogonidae) and/or black flies (Simuliidae), although neither of these species is responsible for transmitting leishmaniasis.