How does HIV entry human body
In an infected person, HIV is present in certain cells (such as Lymphocytes and macrophages) that are found in the tissue as well as in body fluids and secretions. The body fluids involved in HIV transmission are blood, semen, pre-ejaculate fluid, vaginal secretions, and breast milk. Saliva, tears, urine, sweat and cerebrospinal fluid (the fluid around the brain and the spinal cord) have very little HIV that they do not play a significant role in transmitting this Virus. Also HIV is not consistently found in all the fluids from an infected person with susceptible cells in another person.
* HIV is transmitted through penetrative (anal or vaginal) and oral sex; blood transfusion; the sharing of contaminated needles in health care settings and through drug injection; and between mother and infant, during pregnancy, childbirth and breastfeeding.
1. Sexual transmission
HIV can be transmitted through unprotected penetrative sex. It is difficult to calculate the odds of becoming infected through sexual intercourse; however it is known that the risk of infection through vaginal sex is high. Transmission through anal sex has been reported to be 10 times higher than by vaginal sex. A person with an untreated sexually transmitted infection (STI), particularly involving ulcers or discharge, is, on average, 6-10 times more likely to pass on or acquire HIV during sex.
Oral sex is regarded as a low-risk sexual activity in terms of HIV transmission. Risk can increase if there are cuts or sores around or in the mouth and if ejaculation occurs in the mouth.
2. Transmission through sharing of needles and syringes
Re-using or sharing needles or syringes represents a highly efficient way of transmitting HIV. The risk of transmission can be lowered substantially among injecting drug users by using new needles and syringes that are disposable or by properly sterilizing reusable needles/syringes before reuse. Transmission in a health-care setting can be lowered by health-care workers adhering to Universal Precautions.
3. Mother-to-child transmission (MTCT)
HIV can be transmitted to an infant during pregnancy, labor, delivery and breastfeeding. Generally, there is a 15-30% risk of transmission from mother to child before and during delivery. A number of factors influence the risk of infection, particularly the viral load of the mother at birth (the higher the load, the higher the risk). Transmission from mother to child after birth can also occur through breastfeeding.
4. Transmission through blood transfusion
There is a high risk (greater than 90%) of acquiring HIV through transfusion of infected blood and blood products. However, the implementation of blood safety standards ensures the provision of safe, adequate and good-quality blood and blood products for all patients requiring transfusion. Blood safety includes screening of all donated blood for HIV and other blood-borne pathogens, as well as appropriate donor selection.
But it’s important to know how it is not spread. HIV is not spread from one person to another if they have friendly contact such as like shaking hand, hugging, sharing food, coughing, breathing on someone, living or working with infected person, sharing cloth, mosquito and other bug bite. There are no known cases in which any one got HIV through these ways.
During our HIV/AIDS awareness campaign in different Tibetan Settlement and schools, we are often asked; can AIDS be carried from person to person by mosquitoes?
There are three kinds of evidence that H.I.V., the virus that causes AIDS, cannot be carried from person to person by mosquitoes.
First, there is highly compelling epidemiological data from studies of AIDS outbreaks. For example, in sub-Saharan Africa, where mosquitoes are also extremely plentiful, the very people who would get bit most, young children who are outside playing, is the one group that is not H.I.V.-infected. The epidemic is among the sexually active and newborns, except cases involving transfusion.
As for the mosquito being capable of biological transmission, H.I.V. does not grow in any mosquito cells, and the life cycle component of biological transmission is not there, in contrast to malaria, which depends on the mosquito. H.I.V. can’t grow outside cells, and if the viruses don’t infect any mosquito cells they can’t use the mosquito as a biological host.
What about mechanical transmission, in which a trace of H.I.V.-infected blood could be transferred to the next person stung? From what we know about the amount of blood necessary to transmit H.I.V. through a needle stick, it is rather large, almost a visible amount, about a tenth of a milliliter, and given the size of the mosquito’s stinger and the amount that could reasonably be carried from one sting to another, it would require thousands of mosquitoes all biting at once.”