Bio-larvicides

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QUESTION

Why is there no mention here of all the work being done on biolarvicides – the low cost solution for malaria control?

ANSWER

Actually, we had a question a while ago about the ECOWAS program in West Africa, which centers around the use of biolarvicides. A link to that question, and the answer, is provided here: http://www.malaria.com/questions/ecowas-malaria.

The most common form of biolarvicides are those using various microbes, notably Bacillus species, which target mosquito larvae but are harmless to other non-target organisms. A recent study in the Gambia showed very high success rates in killing Anopheles gambiae larvae, when a microbial larvicide using Bacillus thuringiensis var. israelensis strain AM65-52 was applied weekly. Some practitioners are concerned about the amount of effort and man-power a weekly application of larvicide might require, plus the training necessary for correct identification of habitat, but the study in the Gambia seemed to show good compliance once personnel were suitable trained. A link to the study, which is freely available via the Malaria Journal, is available here: http://www.malariajournal.com/content/6/1/76.

 

Malaria Mosquito Eggs

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QUESTION

Where do Anopheles mosquito lay their eggs?

ANSWER

Female Anopheles mosquitoes lay their eggs in standing, often stagnant, pools of fresh water. These larvae can be identified in ponds and puddles because unlike other mosquito larvae, they position themselves parallel with the surface of the water, allowing them to breathe air despite not having a respiratory siphon (instead, they have spiracles on their body).

Different species of Anopheles can tolerate very different larval habitats, including very brackish water (high salt content) in mangrove swamps and estuaries to pristine freshwater and also varying degrees of sun exposure and vegetative cover. Many different fish and aquatic invertebrates can predate on mosquito larvae, many of which have been used in attempts to control mosquito populations throughout the world.

Anopheles Mosquito

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QUESTION

What does Anopheles looks like?

ANSWER

Mosquitoes of the genus Anopheles are responsible for all transmission of malaria in mammals, including to humans. They are night-feeding mosquitoes, usually biting between dusk and dawn, though they may also be active during the day in heavily shaded environments.

Like all mosquitoes, Anopheles are usually found either as freshwater larvae, which prefer stagnant, still water, or flying adults, of which only the females feed on blood (the males exclusively feed on nectar).  Anopheles larvae lie parallel to the surface of the water where they live (in contrast to Aedes and Culex larvae which hang at an angle), whereas the adults rest with their bodies at a 45 degree angle upwards (again in contrast to Aedes and Culex adults, which rest parallel to their resting surface).