Mosquitos are simply nature’s deadliest creature. From Malaria to Yellow Fever, they carry a host of deadly ailments, making them easily more fatal (statistically speaking) than the lion or the bear (BTW, I got this info from TV’s Guiness Book of Records, so I don’t have a cite, sorry 
). Yet a mosquito has never, at least to my knowledge, passed on the AIDS virus. Why is this?
Thank you in advance to all who reply
If I’m not mistaken mosquito-borne diseases actually have a stage of their lifecycle inside the mosquito. The HIV virus would simply get digested, and, also if I remember correctly, mosquitos typically only bite once in their life (or is this an urban legend) and I doubt HIV would mass mosquito-to-mosquito.
Why mosquitoes cannot transmit AIDS
Briefly,
A quick google says the important bit is that mosquitoes dont inject blood they only suck it. Its the mosquitoes saliva where malaria and the other diseases gets transmitted, and the HIV virus doesnt get into their saliva because it hasnt evolved to do that like mosquito borne diseases have.
Otara
I don’t know if this qualifies as an urban legend, but it is almost certainly incorrect for the mosquito species around here. I have, many times, swatted a mosquito which had just landed on me only to be treated to a sizable splat of someone else’s blood. Although possible, I doubt the mosquito in question had landed on me just to rest. More likely, I was dessert.
Now I realize that I’ve been had. I just remembered somebody explaining to me as a child that the female mosquito feeds on blood once, and then flies back to the larvae to be torn to shreds and devoured along with the blood in a great act of motherly self-sacrifice. Although some adult insects do interact with their larval forms, I do not think mosquitos would (aren’t their larvae aquatic anyway?)
Ha! Yeah, you’ve been had. That doesn’t happen. The larvae are indeed aquatic, and the eggs are abandoned by the mother.