I do not know much about Micro Biology
It might surprise you to know that those who do know a lot about it (and those who undestand the detailed virology of HIV, and those who understand the life cycle of the mosquito etc) have given this issue considerable thought, discussion and scientific investigation.
In essence - mosquito bourne diseases such as Malaria are ingested by the mosquito and survive the mosquito's digestion processes - whereas HIV does not. Diseases like malaria can actually multiply inside the mosquito and are found at high levels in mosquito saliva. The mode of infection is through the contaminated saliva - HIV never reaches the saliva, as it is destroyed by the digestive system of the mosquito.
As stated elsewhere mosquitos don't "feed" on blood as such and only (the females) bite to assist with egg development. The life cycle is such that a female only requires one full blood meal every - 3-5 days for each batch of eggs. HIV virus will not survive that long outside a suitable vector (e.g. living person), so the risk of infection between a person bitten in subsequent batches of egg laying is non existent.
As far as the mosquito is concerned the ideal situation is it gets the entire feed from a single host. If the mosquito gets distrurbed it can start its meal on one host and then move to another. This is where the potential risk you describe could arise. The way the probiscus works the only risk is from "residual" virus on the exterior (any material on the inside is being sucked back up to feed on) - so the question then is if there would be sufficient virus present to represent an "infectious dose". The levels of HIV freely circulating in the blood of infected people is usually very low (for this reason tests for HIV typically detect the antibodies the body produces rather than the virus itself). The calculated probability of a single HIV particle being transferred to the second "host" is < 1 in 10,000,000 even if the concentration of HIV particles in the first host's blood is 100x higher than that typically found in HIV carriers. (so if you were bitten 10 million times by a mosquito (or mosquitos) which had very recently (in the last few hours) fed on a person with an exceptionally high level of HIV in their blood you would be likely to get a single HIV virus particle injected into you. This might
give rise to an infection. You would probably die from the itching first!
Originally Posted by Aidan
Meanwhile, there are tens of Millions dying each year from it.
Its not all from Drug addiction or sex, there has to be more to it.
Why not? The epidemiology fits with the known possible (likely) modes of transmission.
If you were telling me that loads of African nuns were getting HIV and no one could explain how then your suggestion would make sense.
Oh and "tens of millions" is a bit of an exageration the WHO estimate is around 3 million for 2006! Estimates of for the known mosquito bourne disease (malaria, nile fever etc) deaths are larger than this.