AIDS is an illness caused by the human immunodeficiency virus or HIV. The virus can survive in human blood and other body fluids.
The reason behind HIV not being transmitted by mosquitoes is the fact that mosquitoes do not inject blood that they have sucked from one person into their next victim. The blood taken from the first person is digested by the mosquito and this process destroys the HIV.
The viruses of illnesses that are spread by mosquitoes are able to survive in the saliva of mosquitoes. This is not the case with HIV.
The reasons provided above have been corroborated by extensive studies conducted by researchers to determine if AIDS could be spread by mosquitoes. It has always been found that HIV cannot spread through this medium.