We all know that there are three ways of transmission of AIDS, sexual transmission is the majority, mother-to-child breastfeeding and blood transmission are the minority, and blood transmission may infect AIDS through blood transfusion. A few years ago, it was reported that the patient was infected with AIDS through postoperative blood transfusion. Finally, it was found that HIV came from the plasma provided by the hospital. This happens when AIDS patients take advantage of the window period of their newly infected AIDS within 2 weeks to donate blood. During this time, HIV antibodies were not detected, so people had an opportunity. Window blank period is a world problem, which cannot be solved. With the improvement of modern detection technology, the window blank period has been shortened.
Many people think that mosquitoes suck blood through blood transfusion. If mosquitoes only suck the blood of an AIDS patient, won't HIV remain on the needle? Why can't this mosquito get infected with AIDS if it bites healthy people again? In fact, if you want to be infected with HIV, your blood must reach a certain dose. According to the data given by the World Health Organization, the minimum dose of a healthy adult male infected with AIDS is 0.2 ml of fresh blood, and the blood left on the mouth by mosquitoes after sucking blood is about 0.00005 ml. In this way, you need 4000 mosquitoes that have just sucked the blood of AIDS patients, and they will immediately suck the blood of another person, so that they can be infected. This situation only exists in theory, and it is completely impossible to happen in reality.
Someone may have thought of another situation. What should mosquitoes do if they spit newly sucked AIDS blood on healthy people? The average blood volume of a mosquito with a full meal is 0.07 ml, and it only takes three mosquitoes to absorb blood volume to make people infected with AIDS, but this situation is actually impossible. The needle used by mosquitoes to suck blood is called mouthparts. It consists of six needles, each of which has a different purpose. The two needles in the upper jaw are called pricking needles, which are responsible for piercing the skin. The two needles in the jaw are enlarged into two serrated knives, which are responsible for sawing the skin and providing periodic puncture force. The last two needles are esophageal tube and salivary tube.
These six needles are clamped together by the shell of mosquito's mouth and work together. The most important thing is the esophageal tube and the salivary tube. When mosquitoes suck blood, they will first use saliva tubes as lubricants to facilitate blood sucking. The vomit contains formic acid, so it makes people feel itchy. Then mosquitoes will suck blood through esophageal tubes. This kind of esophageal tube is unidirectional, that is, it can only suck blood but not vomit blood, so mosquitoes will not spit out the blood absorbed by AIDS patients, and the esophageal tube and the saliva tube are independent when working, and the blood will not be spit out through the saliva tube, so mosquitoes cannot output the absorbed blood independently.
Not only that, after mosquitoes absorb the blood of HIV, HIV will be digested by enzymes in the stomach together with the blood absorbed by mosquitoes. Only a few other viruses can quickly penetrate the stomach of mosquitoes and avoid being digested, such as Zika virus and dengue fever. HIV is effective for human beings, but ineffective for most animals, because the cell membrane of human T cells contains a protein of CD4 molecules, and this protein is easier to combine with HIV virus, making T cells the host of HIV virus, resulting in the loss of T cell function, the damage of human immune system and the easy invasion by common bacterial viruses.