How HIV Is Spread HIV INFORMATION. C o m m u n i t y A I D S R e s p o n s e. HIV Transmission Through Sexual Intercourse. How HIV Infection Occurs

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1 How HIV Is Spread How HIV Infection Occurs In order to gain entry into the body, the HIV virus needs to come into contact and bind to specific target cells with particular receptors, called CD4 receptors e.g. macrophages, dendritic cells and T4 lymphocytes. These receptors enable the virus to successfully attach and gain entry into the blood system of an individual. Healthy skin cells do not contain CD4 receptors, meaning that HIV cannot be transmitted via skin to skin contact without the presence of open wounds. HIV is most frequently spread in one of three ways: - Via sexual intercourse - When HIV infected blood is passed directly into the body (e.g. contaminated blood transfusions, or open bleeding wounds) - From mother to child during pregnancy, childbirth and via breast feeding These are discussed in more detail below. HIV Transmission Through Sexual Intercourse HIV is transmitted from one person to another through the most intimate of contact- sexual intercourse. The virus is found in high quantities in the sexual fluids (semen and vaginal fluid) of people with HIV infection. CD4 receptor cells are plentiful in the lining of the genital tract and the anal/rectal area making these areas particularly conducive to HIV transmission. Although the virus can be found in other body fluids, such as saliva, urine and sweat, according to research, the quantities of the HIV virus present in these fluids are too low for successful transmission. HIV infection has never been reported to have been acquired via a healthy mouth or respiratory tract. However, it is possible to transmit the virus if there are fresh sores of inflammation in the mouth. HIV is not spread via non-sexual, casual contact between people. Individuals who have not had sexual intercourse, or received or shared blood (or blood products) could not have acquired HIV infection. Children remain free from HIV infection even after intimate contact (hugging, kissing) with their infected parents, and after sharing common utensils, baths, linen etc. The presence of other sexually transmitted diseases makes the sexual transmission of HIV easier It is well established that other genital ulcers or sores, caused by syphilis, chancroids, gonorrhoea, herpes virus and other sexually transmitted diseases (STDs), assist the HIV virus in entering the body. The virus can enter the body through the ulcer itself, and attach to the CD4 receptors. These are present on various inflammatory cells, in and around the ulcer.

2 HIV can also be spread from the exposed surface of an ulcer to the genital tract of the infected person s sexual partner. Other STDs, such as gonorrhoea and chlamydial infection, also cause an inflammatory response in the genital tract with a migration of inflammatory cells to the infection. The presence of these cells promotes the successful transmission of HIV. Discharges of fluid that occur with many STDs have a very high concentration of HIV if the person with the STD is HIV positive. The effective treatment of genital ulcer disease (syphilis, chancroid, herpes) and other STDs can play an important role in the control and prevention of HIV infection. Anal or vaginal intercourse Anal sex is the sexual practice carrying the highest risk for transmitting the HIV virus. The lining of the anal-rectal area is relatively easily torn during anal intercourse. This allows the virus to enter the body more easily. Vaginal sex is also an effective form of transmission. If a condom is correctly used during anal or vaginal sex, the risk of transmission is minimised. Oral sex does carry a risk of HIV infection, though it is generally thought to be safer than vaginal or anal sex. The recorded instances of HIV transmission via oral sex have been a result of exposure to semen. Non-penetrative sex, such as sex between the thighs and masturbation, generally carries little risk of HIV transmission. HIV and Blood Transmission HIV infection can occur if infected blood gains entry into the body. For infection to occur, the blood from an HIV-infected person must bypass the barrier of the skin and enter directly into the body. This means that HIV-infected blood becomes a high risk when passed into the body in the following ways: - Through a blood transfusion - Via blood-contaminated needles, syringes, razor blades and other sharp instruments - Through intravenous drug use (sharing of needles and syringes) - It is also possible, though rare, for HIV to enter the body through an open skin wound or sore. It is important for all blood to be tested for HIV before it is regarded as safe for blood transfusion, it is also important for health care workers to be careful when using sharp instruments, taking

3 blood, putting up drips, doing invasive surgical procedures and handling blood-stained dressings, linen or instruments. Mother to Child HIV Transmission (MTCT) Pregnancy and childbirth A pregnant mother, who is infected with HIV, can pass on the virus to her infant during pregnancy and childbirth. In recent years a better understanding of MTCT and the ways to prevent it has developed. Research has shown that there is a 20-30% chance that the infant will become HIV positive without prophylactic antiretroviral therapy during the mother s pregnancy. Advancements in recent years have given medical professionals much more insight as to what increases the risk of mother-to-child-transmission, and how those risks can be mitigated. The United States Center for Disease Control reports that with the use of ARV drugs before and during childbirth, the risk of mother to child transmission as a result of pregnancy is reduced to less than 2%. A woman is more likely to transmit the virus to her foetus during pregnancy if: - She is not on ARV treatment - She becomes infected just before or during pregnancy - She has a high HIV viral load - She has symptomatic HIV disease - She has a low CD4 count This means that a symptomatic mother is more likely to pass the virus than a mother who has no symptoms of HIV disease. There are many ways to reduce the risk of MTCT during labour. These include: - The use of anti-retroviral therapy prior to and during labour - Disinfection of the birth canal (vaginal cleaning) - Avoiding unnecessary rupture of the membranes and episiotomy - minimising trauma of the foetus - Giving birth via Caesarean section Breast feeding The issue of infant feeding in low resource and low socio-economic communities is a complex issue. There is an HIV transmission risk to the foetus from breast feeding, but consistent access to formula and clean water must be considered. Health professionals agree that exclusive feeding is critical in order to deduce risk of infection feeding either by breast milk or formula exclusively.

4 Current UNAIDS guidelines recommend that breastfeeding be avoided by HIV positive mothers anywhere that formula feeding is acceptable, feasible, affordable, sustainable and safe. Health care workers will need to carefully inform and advise mothers in relation to their circumstance. The Most Infectious Phases for HIV-Infected People There are certain periods of time during which a person is at increased risk of transmitting HIV. During the first 4-8 weeks after becoming infected they are more likely to pass the virus to others. When there is a high HIV viral load present, likelihood of transmission also increases. People who display symptoms of HIV/AIDS infections have a higher probability of infecting others as the virus advances in their system. This is because there are larger quantities of the virus in the blood stream at these times. Remember that it is possible to transmit HIV at any time following infection. Casual Contact Does Not Spread HIV HIV is not spread through normal, everyday, casual contact between individuals. - The HIV virus is not stable and does not survive for long periods outside the human body. - The virus cannot penetrate normal intact skin and does not readily enter through a healthy mouth or eye. - The virus is not present in high enough quantities in tears, saliva, faeces and urine to cause infection. Sweat carries no HIV. HIV is not transmitted by the following means: - Airborne routes, such as coughing, sneezing, laughing, talking and kissing - Simple skin contact, such as hand-shaking, hugging and touching etc. - Food, water, or on plates, cups, spoons, toilets, baths, pools and showers etc. - Towels, bed linen, clothes, etc. - Insects, such as mosquitoes, are not known to spread HIV from one person to another.

5 The Influence of Poverty on the Spread of HIV AIDS and other sexually transmitted diseases are often more common in lower socio-economic countries. Some of the reasons why low socio-economic conditions promote the spread of sexually transmitted diseases are as follows: - The relationship between men and women suffer. Women are often exploited and viewed as having an inferior status to men. In many countries women have very little control over their sexual lives, and methods of STD prevention (condom use etc). Poverty often increases the risk of sexual exploitation, and this further contributes to the spread of sexually transmitted diseases. - High unemployment promotes migrant work and family disruption. People leave their homes, families and local community life. Working in industrialized cities, migrants often find themselves in lonely, unfavourable, hostile or alienating environments. The effort to dispel loneliness often results in multiple-partner sexual relationships. - Women, and sometimes children, are often forced to sell sex to earn precious money or food and basic needs in an effort to support their families. - People in poor living conditions often lack easy access to heath care services so sexually transmitted diseases often go untreated and spread more easily. - People often abuse alcohol and/or drugs as an escape from everyday hardships. Substance abuse impairs judgement and increases a person s willingness to have sex with multiple partners. - Crime and violence is also common in cities and towns where large populations live in poverty, and these further stress family and community life. - Poor educational opportunities and low literacy levels keep people ignorant regarding ways of preventing diseases and infections like HIV. - Many of the problems described above also result of the breakdown of the usual traditions, customs, beliefs and the cultural practices in the community. These practices usually protect the vulnerable and determine the accepted sexual behaviour and constraints in society. Without cultural norms, there is an increased risk of sexual exploitation and abuse. There are many reasons why HIV is spreading. Prevention and care measures need to take into account socio-economic factors that promote the spread of HIV.