There is concern that a mosquito that bites an HIV-positive person can pass the infection on to its next victim. We decided to check whether this method of transmission of infection is possible.

According to survey Izvestia reports that every sixth Russian is sure that one can become infected with HIV through mosquito bites. Questions from concerned citizens are regularly answered by experts in various media: such publications have been "Arguments and facts", Lenta.ru, "Things like this".

HIV, the human immunodeficiency virus, is a retrovirus. It causes HIV infection in humans, a slowly progressive disease that, in the absence of special therapy, results in the development of acquired immune deficiency syndrome (AIDS). Scientists installedwhat a virus formed at the end of the 19th or beginning of the 20th century, and then somehow passed on from monkeys to humans.

Earliest documented specimen of HIV in a human was discovered in 1959 in a blood sample from a British sailor. Robert Rayford, a teenager from Missouri, counts zero patients in the US. Presumably (Robert himself denied this during his lifetime), he was engaged in homosexual prostitution. Symptoms of the disease were recorded in 1966, and in 1969 the teenager died. Then the doctors were unable to establish the exact cause of his death, indicating “loss of vitality of the body” instead of the diagnosis. Laboratory samples of his tissues, unfortunately, were destroyed in 2005 due to the violence of the elements during Hurricane Katrina.

The HIV epidemic began in sub-Saharan Africa in the 1970s. By data WHO, in 2019 there were approximately 38 million people living with HIV worldwide.

The human immunodeficiency virus was simultaneously open in 1983 at the Pasteur Institute by Luc Montagnier and at the National Cancer Institute in the USA by Robert Gallo. In 2008, Luc Montagnier with his colleague Françoise Barre-Sinoussi received Nobel Prize in Physiology or Medicine "for the discovery of the human immunodeficiency virus."

To date installedthat the virus is transmitted through damaged or intact mucous membranes, upon contact of the damaged skin of a healthy person with the biological fluids of an infected person (blood, pre-seminal fluid, sperm, vaginal secretions, breast milk). Transmission of the virus can occur through vaginal, anal and oral sex, through the use of syringes with contaminated needles, blood transfusions, during pregnancy and childbirth, during breastfeeding (both from a nursing woman to a child and vice versa). According to experts, the virus is not transmitted when kissing, since salivary enzymes destroy virions. Bites from blood-sucking insects are also not represent danger. There are several explanations for this.

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Firstly, when an insect bites, it does not inject someone else’s blood into the bitten person, but sucks it out. Mosquito proboscis consists of of six tubes, four of which the mosquito uses to pierce the skin, one to introduce saliva with special blood-thinning enzymes into the host’s skin, and another to absorb the victim’s blood. The movement of liquid in this tube occurs in only one direction: inside the insect’s body. The blood that can sometimes be seen around the wound is not from the previous victim, but from ours own.

Secondly, the human immunodeficiency virus is so called, among other things, because it can live only in the human body. For virus replication necessary contact special cells - T-lymphocytes, which are present in humans, but are absent in the digestive tract of a blood-sucking insect. A mosquito that has drunk the blood of an HIV-infected person completely recycles virus along with other food.

Thirdly, HIV is present in the blood of the infected person in insufficient quantities for infection in this way. By calculations According to scientists, in order to introduce into the body of a healthy person the concentration of the virus necessary for infection, it would take 10 million mosquitoes, which would have previously bitten a person with HIV infection.

However, if we talk not only about mosquitoes, but about all blood-sucking insects, then the situation changes somewhat. Eat assumptionsthat the fly Stomoxys calcitrans - the autumn fly - could be the very insect that initially transmitted the virus from monkeys to humans. The digestive system of this fly is structured in a slightly different way: the animal does not completely digest the blood it drinks, but stores part of it in a special “pocket” in the intestine, which does not contain digestive enzymes. With the next bite, the fly can regurgitate this stored blood at the site of the bite. Not all scientists agree with this hypothesis. Professor David Mabey from the London School of Hygiene and Tropical Medicine believes: “This is an interesting theory and nothing more. The main thing now is to practice safe sex, and not worry about which fly bit you.”

Thus, transmission of HIV infection through a mosquito bite is impossible for many reasons. This does not negate the need to use mosquito nets and repellents, since mosquitoes carry malaria, yellow fever, Zika fever and heartworm disease.