Raising Awareness - Educating - Building Community
HIV Transmission
Contrary to some popular misconceptions, HIV is a difficult disease to get. Below we talk about the ways HIV is spread - and how it is not spread.
Three conditions must be met for HIV transmission to occur:
HIV Must Be Present
Infection can only happen if one of the persons involved is infected with HIV. Some people assume that certain behaviors (such as anal sex) cause AIDS, even if HIV is not present. This is not true.
There Must Be A Sufficient Quantity of HIV
The concentration of HIV determines whether infection may happen. In blood, for example, the virus is very concentrated. A small amount of blood is enough to infect someone. A much larger amount of other fluids would be needed for HIV transmission.
HIV Must Get Into The Bloodstream
It is not enough to be in contact with an infected fluid to become infected. Healthy, unbroken skin does not allow HIV to get into the body; it is an excellent barrier to HIV infection. HIV can only enter through an open cut or sore, or through contact with the mucous membranes in the anus and rectum, the genitals, the mouth, and the eyes.
| Infectious Body Fluids |
Non-infectious Body Fluids |
| Blood (including menstrual blood) |
Saliva |
| Semen |
Tears |
| Vaginal secretions |
Sweat |
| Breast milk |
Feces |
| |
Urine |
Blood contains the highest concentration of the virus, followed by semen, followed by vaginal fluids. Breast milk can also contain a high concentration of the virus, but in this situation, transmissibility depends on WHO and HOW. An adult can ingest a small amount of breast milk at no probable risk. But an infant, with its very small body and newly forming immune system, consumes vast quantities of breast milk relative to its body weight. Therefore an infant is at risk from breast milk, whereas an adult may not be.
HIV might be transmitted from an infected person to another from pre-seminal fluid (pre-cum). Although it is difficult for researchers to analyze definitively, it is thought that HIV may be transmitted through pre-cum (this is a clear fluid that lubricates the urethra for semen). Pre-seminal fluid can contain semen or white blood cells, both of which have HIV in an infected person. So going back to conditions required for transmission, HIV can be present, but it is present in a relatively, small amount, compared to semen or blood. Therefore, pre-seminal fluid presents a much lower risk for HIV transmission than ejaculate, but there is some risk, depending on where this fluid is going (as in all transmission situations).
Sexual Routes Of Transmission
Vaginal and anal intercourse without the use of a condom is considered high risk for HIV infection. In the genitals and the rectum, HIV may infect the mucous membranes directly or enter through cuts and sores caused during intercourse.
Oral sex (Mouth-Penis, Mouth-Vagina) is low risk for HIV infection. However, this does not mean no risk. Generally speaking, the mouth is an inhospitable environment for HIV. As a result, the risk of HIV transmission through the throat, gums, and oral membranes is lower than through vaginal or anal membranes. There are however, documented cases where HIV was transmitted orally, so we can't say that getting HIV-infected semen, vaginal fluid or blood in the mouth is no risk. Avoid brushing, flossing and dental work an hour before, or immediately after, performing oral sex, as doing so can cause small tears and cuts in the mouth and provide a route of entry for HIV into the bloodstream.
Sex toys may also pose a risk for HIV infection. Transferring a sex toy directly from one partner to another allows for sharing of infected fluids that can result in direct HIV transmission. The risk of HIV transmission can be reduced by cleaning sex toys after use (soap and water, alcohol or bleach).
In the immediacy of a sexual situation, some people may use a condom as a substitute for cleaning. After using a condom with one person, replace it with a new one before the toy is transferred to another person. There is some risk involved with this method because of the possibility that the condom can break, slip off or not completely cover the surface of the toy.
Using sex toys (e.g.: dildos, vibrators, Chinese balls, butt plugs, anal beads) and other objects can cause trauma to the mucosal lining of the rectum or vagina. The extent varies depending on the size of the device and the way it is used. Even if properly cleaned and therefore not directly transmitting HIV, trauma and resulting inflammation can promote the possibility of later transmission by opening a route of entry for HIV to the bloodstream through the cuts or tears in the rectum or vagina, thereby increasing the risk of HIV transmission for other activities that may follow.
Non-Sexual Routes Of Transmission
Needle sharing:
Sharing a needle can pass blood directly from one person's bloodstream to another. It is a very efficient way to transmit a blood-borne virus. HIV can survive for several days in the small amount of blood that remains in a needle after use, so used needles are very risky for HIV transmission; they provide a direct path into the bloodstream. Ideally, used needles should never be reused, but if they are, they should always be cleaned with bleach or alcohol before re-use.
Tattooing, Piercing, Acupuncture, Electrolysis,and Shaving: Any procedure in which a needle or razor is used on more than one person involves a theoretical risk of HIV transmission because of the possibility of infected blood on the instrument. However, the risk can be reduced or eliminated through routine sterilization procedures. There are no documented cases in the United States of someone becoming infected through tattooing or piercing.
Blood Transfusions:
Since March 1985, all blood in the Canada has been screened with the HIV antibody test. This practice has almost ,eliminated the risk of getting HIV through a blood transfusion.
Hemophilia Treatments:
Hemophilia is a genetic disease in which people (almost all men) lack the ability to clot blood. To control the condition, hemophiliacs take Factor VIII, a clotting factor. Each dose of Factor VIII comes from the pooled blood of many donors. Currently, over 90% of hemophiliacs in the U.S. have been infected with HIV because of receiving contaminated Factor VIII. Factor VIII is now heat-treated to kill the virus. In addition, there are new synthetic products that do not pose any risk for HIV and which accomplish the same function.
Other Blood Products: Besides whole blood, platelets (red blood cells) have transmitted the virus. Current blood screening, however, should prevent all but a very, very few cases. No other blood products are suspected of transmitting HIV. Gamma globulin or hepatitis B vaccine do not transmit HIV. Gamma globulin, however, can temporarily transmit HIV antibodies, although not the virus itself. These antibodies will disappear within a few months.
Mother to Child:
It is possible for an HIV-infected mother to pass the virus directly before or during birth, or through breast milk. Approximately 20% of babies born to HIV-positive women who undertake no transmission-reduction measures will be infected with HIV. Taking AZT during the later stages of pregnancy and delivery reduces this probability to 5% - 8%. Recent studies presented at the 12th World AIDS indicate that transmission is reduced to less than 2% if a cesarean section (c-section) is performed prior to labour, in combination with AZT therapy. Other studies are being conducted to determine whether vaginal cleansing and use of anti-viral vaginal suppositories prior to birth are effective in reducing mother-to-child, or "perinatal," transmission.
Breast Milk:
Breast milk contains HIV, and while small amounts of breast milk do not pose significant threat of infection to adults, it is a viable means of transmission to infants. The United Nations presented a recommendation at the 12th World AIDS Conference suggesting ,that infected mothers not breast feed their ,infants. Despite use of AZT by the mother, approximately 5% of vertical transmission occurs via breast milk.
Semen Donor Insemination: Donor semen is checked for HIV antibodies when the semen is collected. The semen is then frozen. The donor is required to come back after six months for a second HIV test, to confirm the initial HIV screening. The semen is not used before the procedure is completed.
Occupational Transmission
A study of over 2,000 health care workers has been underway for several years to assess the risk of their exposure to people with AIDS. Over 1,000 of these workers had a needle stick accident with a needle that had been used on a person living with AIDS. The rest had some sort of mucous membrane exposure, such as being splashed in the face with blood or vomit. It is estimated that only three people in a thousand will become infected with HIV by a needle stick.
Of all these people, only 21 show signs of being infected with HIV (as determined by the antibody test). One of these people was a nurse who had multiple needle stick accidents, including one where she tripped and fell on the depressor of a syringe full blood, and the entire contents entered her body. Another was a lab worker who was working with a test tube of infected blood which broke and cut his finger, exposing the infected blood to his bloodstream. This study shows that AIDS is a difficult disease to get, and even the intimate exposure of these health care workers was not enough to infect them, except in the most extreme cases.
HIV Transmission Myths
Insect Bites:
HIV is not transmitted by mosquitoes, flies, ticks, fleas, bees or wasps. If a bloodsucking insect bites someone with HIV, the virus dies almost instantly in the insect's stomach (as it digests the blood). HIV can only live in human cells.
Mosquitoes Cannot Transmit HIV For Two Reasons:
• The mosquito draws blood and injects saliva. The blood from one person is not injected into the mosquito's next victim.
• HIV dies in the mosquito's body. People sometimes are confused because malaria actually reproduces inside the mosquito's digestive track, using the insect as part of its life cycle. HIV does not.
These facts are confirmed by looking at infection patterns. In areas where mosquitoes are common and where HIV is prevalent, the distribution of AIDS cases in the population is not different from other areas. If mosquitoes transmitted HIV, we would be seeing a disproportionate number of children and elderly infected in those areas.
Casual Contact/Sharing Dishes or Food:
HIV is not transmitted through casual, every day contact. Since HIV is not transmitted by saliva, it is impossible to get it through sharing a glass, a fork, a sandwich, or fruit.
Three studies of household contacts, in the US, Europe, and Africa, have shown that AIDS is not casually transmitted by normal activities, even when people are in close living arrangements. All the studies examined households where someone had AIDS to see if any of the other members in that household had become infected (sexual contact was excluded). Many of these households included a small child as the one who has AIDS. These children continued to play with siblings in the manner that children play: wrestling, fighting, spitting, sharing food and clothes, and many other activities. No other member of any of the households shows any sign of being infected. This study shows that AIDS is a difficult disease to get, and that even the intimate exposure common among small children living together is not sufficient to transmit the virus.
Donating Blood: Sterilized needles are always used in taking blood from donors, so HIV is not spread in this manner.
Swimming Pools and Hot Tubs: The chemicals used in swimming pools and hot tubs would instantly kill any HIV, if the hot water hadn't killed it already.
Pets: Humans are the only animals that can carry HIV. People sometimes think they can get HIV from pets, because some animals carry viruses that produce similar immune deficiencies in their own species, e.g. FIV, feline immunodeficiency virus, in cats, and SIV, simian immunodeficiency virus, in some types of monkeys. However, FIV cannot be transmitted to people, nor can HIV be transmitted from humans to pets such as cats and dogs. (An exception is chimpanzees used in research that have been infected with HIV. Their blood poses a risk to researchers working with them). There have been two reported cases of transmission of SIV to researchers, but no one knows if the virus will cause disease in them.
Contact with Saliva, Tears, Sweat, Feces or Urine: Transmission can only occur when a sufficient amount of HIV enters the bloodstream, through cuts or mucous membranes. These body fluids either contain no HIV or it exists in a quantity too small to result in transmission.
HIV is not transmitted by saliva. There is a great deal of evidence to support this fact. In a study of 79 men with AIDS, the virus could be found in the saliva of only one. This man had PCP, thrush, and other mouth and throat lesions. Even in this man, the level of virus found in his saliva was 10,000 times less than the level in his blood. To this study we can add the evidence of the countless numbers of people who have had saliva contact with people with AIDS or others who have been infected. This contact has occurred through kissing, sharing food, sharing joints, and many other means. We can find no evidence that these activities have transmitted the virus even a single time. Recent findings suggest that saliva contains an enzyme which kills HIV. Certainly there is a lot at work in the mouth combining to make the mouth an inhospitable site for the virus: acids, enzymes, friction, dilution, air, and more.
