Mosquito bites can be more than just itchy and annoying. While most of these bites are harmless, mosquitoes can carry diseases, such as malaria and Zika.

In fact, mosquitoes are one of the deadliest animals on the planet when you factor in all mosquito-borne diseases.

Some people think mosquitoes can also transmit HIV. However, this isn’t true.

Read on to learn more about why it’s impossible for a mosquito to transmit HIV to humans.

Even if a mosquito bites a person with HIV, then bites someone else, they can’t transmit HIV to the second person.

This is because of the mosquito’s biology, and the biology of HIV itself. Mosquitoes can’t transmit HIV for the following reasons:

HIV doesn’t affect mosquitoes, so they can’t transmit it to humans

HIV latches on to receptors on the surface of immune cells. It can then affect those cells, replicate, and spread.

Mosquitoes (and other insects) lack the receptor HIV uses to recognize immune cells. This means that mosquitoes can’t get an HIV infection. Instead, the virus just gets broken down and digested in the mosquito’s stomach.

Because they can’t get an HIV infection, mosquitoes can’t transmit HIV to humans.

A mosquito’s feeding mechanism

A mosquito’s proboscis — the elongated part of its mouth it uses to bite humans — has two tubes.

One tube is used for sucking blood from humans. The other injects saliva into the bite. This means only saliva, not blood (from either a mosquito or another person) goes into your body when you get a mosquito bite.

HIV can’t be transmitted through saliva, so it can’t be transmitted through a mosquito’s bite.

It would take too many bites

HIV actually isn’t very easily transmittable. It takes a large amount of the virus being transmitted for someone to contract it.

Even if some HIV were still in a mosquito’s body when it bit you — if it had yet to be fully digested — there wouldn’t be enough of it to transmit to you.

HIV is transmitted through direct contact with certain bodily fluids that contain HIV. These fluids include:

These fluids must enter the person’s body for them to contract HIV.

HIV is mainly transmitted through sex without a condom or other barrier method, and through the sharing of needles.

In some cases, HIV can be transmitted during pregnancy, childbirth, or breastfeeding. However, antiretroviral therapy can greatly lower the risk of this occurring, and it’s safe to take during pregnancy.

HIV is highly unlikely to be transmitted through saliva.

HIV can only be transmitted when a person with the virus has a detectable viral load (the amount of HIV in their blood). Taking daily medication (antiretroviral therapy) for HIV can lead to an undetectable viral load, which means HIV can’t be transmitted to others.

Although mosquitoes can’t transmit HIV, there are many diseases they do transmit.

Mosquitoes in different parts of the world transmit different diseases. This is due to the fact that different pathogens thrive in different environments. In addition, different mosquito species often transmit different diseases.

Diseases that mosquitoes transmit include:

Mosquito-borne diseases are the most common and dangerous threat from mosquitoes. But in rare cases, mosquito bites can also cause severe allergic reactions.

The itchiness you feel after a mosquito bite is a type of mild allergic reaction. But some people can have a stronger reaction, including hives or lesions around the bite.

Medical emergency

If you have trouble breathing or swelling in your face or throat after being bitten by a mosquito, call 911 or go to the nearest emergency room immediately. These are symptoms of a serious allergic reaction called anaphylaxis, which can be life threatening.

There are many diseases that mosquitoes can transmit, but HIV isn’t one of them.

Mosquitoes can’t get an HIV infection because they lack the cell receptors HIV needs to latch on to.

However, it’s important to still take care to protect yourself from mosquito bites as much as possible.