Many people are concerned that these blood-sucking insects can transmit the deadly HIV virus. Here are three explanations why this is virtually impossible to happen.
Firstly, the virus responsible for the AIDS infection is regarded as food to the mosquito and is actually digested.
Secondly, mosquitoes can't carry enough units of HIV to initiate infection. According to some calculations, 10 million mosquitoes that had begun feeding on an AIDS carrier would have to bite an AIDS-free person to transmit just a single unit of HIV.
Another important reason is that mosquitoes are not actually "flying syringes" as some people think and cannot transmit the virus as such. The point here is that the mosquito's feeding apparatus is so extremely complicated that the blood flow is always unidirectional and the saliva that is regurgitated before the feed flows in a separate passageway. Therefore it is impossible for a mosquito to flush out the remnants of its last blood meal.