Why Mosquitoes Can't Transmit HIV

HIV/AIDS kills about 1.6 million people every year, according to the most recent World Health Organization data. Hopefully, high school health classes taught us all how to avoid contraction: Don't have random, unprotected sex or use dirty needles.

Mosquitoes function the same way as hypodermic needles though — They can both inject chemicals and extract blood. And if mosquitoes carry West Nile Virus and other blood-borne diseases, shouldn't they logically be able to transmit HIV, too?

Thankfully, we were reassured that that's not the case. Mosquitoes can not transmit HIV.

"It's definitely not a stupid question," Joe Conlon, former Navy entomologist and current technical advisor for the American Mosquito Control Association, told Business Insider.

Conlon explained that first of all, when a mosquito bites you, it draws your blood into its gut. Acids there kill the HIV virus. Plain and simple.

Even if the mosquito's stomach acids didn't render the virus harmless, it wouldn't be able to get back out of the insect. 

That's because mosquitoes use two different tubes to suck up blood and to inject you with saliva that stops your blood from clotting up while it's drinking. Even if a mosquito had virus-containing blood from another human inside it, the blood would never exit the bug through its salivary glands and into your blood stream.

"For a mosquito to transmit a disease, it's gotta pick up the virus. The virus has to survive in the gut and then get outside the gut into the body cavity and then eventually into the salivary glands to be injected into something else. It's a very complicated process, and with HIV, it just doesn't happen," Conlon said.

Malaria parasites, on the other hand, are able to grow in the mosquito gut, then migrate specifically to the salivary glands to continue their lifecycle in another human.

Thank goodness HIV doesn't have that ability. If mosquitoes spread HIV the way they spread Malaria, we'd have a million more deaths every year on our hands.