What is a Sexually Transmitted Infection (STI)?
Some STIs cause infection of reproductive organs, others like HIV, Hepatitis B, Syphilis cause general body infections. Failure to diagnose and treat STIs at an early stage may result in serious complications and sequels (infertility, fetal wastage, ectopic pregnancy, anogenital cancer and premature death, as well as neonatal and infant infections, etc.). There is a strong correlation between the spread of conventional STIs and HIV transmission, and both ulcerative and non-ulcerative STIs increase risk of sexual transmission of HIV.
What is HIV?
The Human Immunodeficiency Virus (HIV) causes AIDS (Acquired Immune Deficiency Syndrome). HIV was first described in 1983. It is a retrovirus differing from other viruses by its special way of multiplication. It infects the immune (or defense) system and damages or destroys white blood cells of the body – called CD4 or T4 lymphocytes – of the body. The T4 cells are responsible for coordinating the complex functions of the body’s immune system. HIV is also able to infect other cells of the immune system, brain cells and gut cells. When too many CD4 cells have been destroyed, patient’s immune system is no longer able to fight against infections, called Opportunistic Infections (OIs).
Like other viruses, HIV is only able to multiply inside the cells of the infected person. But, although viruses contain the genetic material to make new viruses they lack the machinery to do so. The genetic material of HIV becomes part of the genetic material of the host cell. When the infected host cells multiply, each new cell contains the genetic material of HIV. In this way, HIV sets up a permanent infection. When infected cells are stimulated they produce new viruses.
What is AIDS?
Most of the patients with HIV infection will develop AIDS. It is called a “syndrome” because an infectious disease has several signs and symptoms. Until now, there is no effective cure to eradicate HIV, but treatments can slow down its progression towards AIDS, prevent and treat opportunistic infections.
How does the virus spread?
HIV is not a very active virus. To cause infection, the concentration of the virus in the infected fluid must be high. HIV is present in sexual secretion, blood and breast secretion. HIV is spread when blood, semen, or vaginal secretion of an infected person comes in contact with the blood or mucous membranes of a healthy person. It may also be transmitted during breastfeeding from a mother to her baby.
Transmission through sex
Sexual activity is the most common route of transmission of HIV. The presence of STIs, increases the risk of both acquiring and transmitting HIV in men and women. Training health workers, providing simple antibiotics and public education to prevent and treat STIs can reduce the incidence of HIV by about 40%. Other infections of the reproductive tract, such as thrush (Candidiasis) and Bacterial Vaginosis, may also increase vulnerability to HIV. With regards to prevention, this is important, because these are common and easily treatable conditions.
Young women are especially vulnerable to HIV. HIV is more likely to spread when sexual activity is rough or repeated frequently. Anything that increases the risk of vaginal abrasion is likely to increase the risk of transmission. There is evidence that uncircumcised men are at greater risk of becoming infected with HIV than circumcised men. Women may be especially vulnerable to HIV infection when pregnant and postpartum. Both male and female condoms reduce the risk of transmission through sexual intercourse.
Transmission through blood
Injecting drug use is becoming increasingly common in many countries, especially Asia. HIV and other blood-borne viruses spread very easily between people who inject drugs together and share needles, syringes and other injecting equipment. Blood drawn back into the syringe can pass directly into the bloodstream of the next person to use the syringe. HIV can then spread from infected drug users to others in the population through sexual intercourse or through blood transfusion.
Transfusion of contaminated blood can transmit HIV. Whole blood, red blood cells, platelets, plasma and clotting factor concentrate may contain HIV. Routine testing of blood for transfusion greatly reduces the chances of transmitting HIV through blood transfusions, but there always remains a risk. This is because a donor can give blood after infection, but before they have developed antibodies, and before the test has become positive – i.e, the donor in window period condition.
Detailed interview and physical examination in addition to blood testing are very important in screening potential donors before they give blood. In some countries routine screening of blood for transfusion is still not available everywhere. Some blood product manufacturers and commercial blood banks re-use needles and do not sterilize equipment. This practice has caused some paid blood donors to become infected. Strict criteria for blood transfusion can reduce transfusions greatly without increasing mortality.
HIV can also be transmitted from one person to another through transplantation of any organ or tissue. It is essential to screen the donor for HIV antibodies before any transplant, including corneal and skin grafts.
How is the virus not spread?
HIV spreads in three ways: through sexual intercourse, through blood, and from mother to child. Unprotected sex and sharing needles or syringes for injecting drug use with an infected person carry a high risk of infection. Infection through blood transfusion is a common problem in areas where blood donations are not screened for HIV.
The virus cannot be transmitted by coughing or sneezing; by shaking hands; by sharing a drinking glass, plates or cutlery; by hugging or kissing; by insect bites; by walking barefoot where people have spat; or by living or working with someone who has AIDS or HIV infection.
The virus is not present in saliva, sweat and tears. It is not spread by domestic animals neither by mosquitoes.
Things that do not transmit the AIDS virus: food, water, drinks, shower, swimming pool, gymnasium, cutlery, public places like toilets, cinema, work place, school, taxi, and buses. The pattern of transmission depends on behavior patterns and varies from place to place, and in different groups within a population. HIV spreads rapidly where there is poverty or inequality.
How HIV attacks the body?
During the first few weeks after exposure to the virus, HIV multiplies rapidly inside the person’s body. During this initial window period of infection, before the production of antibodies, a person is infected and may transmit the virus to others, but may be unaware of being infected. A test for antibodies during this window period may also not be an accurate result. However within three months, the person starts to produce antibodies to HIV. This process is called sero-conversion. Most of these antibodies produced by the body are not neutralizing antibodies; they cannot overcome the infection.
Many people experience an acute illness at the time of sero-conversion, with fever and enlarged lymph glands. Some have neurological symptoms. The illness lasts about 14 days, and may be mistaken for glandular fever, Dengue fever or Flu. Many people infected with HIV are unaware they have become infected with HIV and have no symptoms for months or years. This period of silent infection is called the latency period. During the latency period the virus is replicating slowly and there are low levels of virus in the blood. The HIV antibody test if taken during this period will be positive. The latency period is long and variable, and may range from four months to more than 10 years.
Over time, the number of T4 cells decreases and infected people develop clinical symptoms. They may suffer a wide range of symptoms including loss of weight, tiredness, fever, cough and diarrhea.
Acquired Immune Deficiency Syndrome, or AIDS, is the name given to the final stage of HIV infection when the immune system is very weak and many micro-organisms have the opportunity to infect the person. These infections are called opportunistic infections (OIs). The weak immune system may also allow cancers to develop. Tuberculosis, Pneumocystis Carinii Pneumonia, fungal infections and Cryptococcal Meningitis are OIs commonly seen in AIDS patients. HIV-infected women may also suffer from severe vaginal herpes, Candidiasis (thrush), and pelvic inflammatory disease, and are more likely to develop cervical cancer.
What happens when the AIDS virus (HIV) enters the body?
AIDS is the final stage of HIV infection. At this stage, other diseases are able to infect persons. Following the infection with HIV, about 1/3 of infected patients will develop AIDS within five years, and 2/3 will develop it within 12 years.
First step – Primary infection: 3 weeks – 6 months
During the week following the primary infection, 20% to 30% of the subject may develop pseudo influenza, pseudo-mononucleosis manifestations or glandular fever. Others experience no symptoms and most patients remain healthy with no signs of illness for many years. However, HIV is present, and the person can infect others without knowing it. Infected subjects start to produce antibodies against HIV which can be detected on serological test between three weeks and six months after the initial infection. They are seropositive.
Second step – Subsequent course: 6 months – 10 years
During the second step of the infection, some patients may develop clinical symptoms and signs and develop AIDS. The deficiency of the immune system can be increased by malnutrition and cancers.
Third step – Severe form of HIV infection, the illness of AIDS
During the 10 years following the infection by HIV, 60% of seropositive subjects will develop major signs like opportunistic infections, certain cancers or other manifestations involving neurological problems.
