HIV

Before 1980s HIV virus was unknown to the world. In 1981, a rare type of pneumonia was reported from various parts of  Los Angeles in U.S. PCP (Pneumocystis carinii pneumonia) was known to cause lung infections in immuno suppressed individuals. But the occurrence of PCP in fine healthy men caused a dilemma among physicians. The single common factor connecting these five men from different parts of L.A was their sexual orientation. All five were homosexuals. In the same period, a rare cancer seen on skin (Kaposi Sarcoma) was spotted among homosexual men who lived in various American cities. The profound immune suppression found in these apparently healthy young men made the experts conclude that this was sexually transmitted. Hence it was first called GRID (Gay Related Immune Deficiency) in 1982. Later when similar immune suppression was found among those haemophiliac patients, who had received several units of blood, the condition was renamed as AIDS or Acquired Immuno Deficiency Syndrome.

The virus causing this immune-suppression- the HIV (Human Immuno Deficiency Virus), was identified even later, in 1982. Several similar cases got reported from various parts of the world during this period.

The experts in India had firmly believed that this was a ‘disease of the western World’ and would never reach India. But in 1986, a series of blood tests among the commercial sex workers in Chennai, showed positive HIV results in six women. The senior medical professionals found this revelation surprising and even refused to believe it initially. In the years to follow, it was realized that HIV infection had affected a good number of Indians and had become a major public health concern in the country.

The origin of HIV was widely researched upon. Genetic studies pointed that HIV resembled SIV (Simian Immuno Deficiency Virus) which was found in several types of monkeys of the African regions. It is believed that SIV got transmitted from monkeys to humans and later evolved to the present form of HIV.

 There are two types of HIV, HIV-1 and HIV-2. Gene analysis shows separate genetic lineage for these two types. HIV-1 originates from a type of Chimpanzee, where HIV-2 originates from an old world monkey called Sootey Mangabey. HIV-1 is the widely prevalent type and is seen from the countries across the world. HIV-2 is largely restricted to Western Africa, some European and Asian countries. It is also seen in some areas in India. HIV-2 affects the human body at a slower rate. HIV-2 affected individuals might remain apparently healthy for around 10 years without any symptoms.

How is HIV transmitted?

1)     Through unprotected sex: Majority of the HIV affected individuals in India and the world contracted HIV through unprotected (without condom) sexual intercourse. The chances of getting HIV from a single act of unprotected sex with an HIV infected individual may be less than 1%. But regular sexual acts with an HIV positive partner can increase the risk to around 40%. These risks vary with various factors. For eg, the receptive partner in a sexual act has higher chances of contracting HIV. Higher likelihood of injuries in the receptive partner during the sexual act enhances the risk of transmission. The higher concentration of HIV virus in the semen compared to vaginal fluids also results in enhanced risk in receptive partner. For the same reasons, receptive partner in an anal intercourse also is at higher risk.

2)     Through blood transfusion: receiving blood or blood products from an HIV infected individual can result in HIV transmission with a risk over 90%. Direct entry of virus through larger quantity of blood is the reason of higher risk of transmission. In India, those who got HIV through blood transfusion constitutes less than 2% of the total number of HIV infected people.

3)     Mother to child transmission: the chances of HIV transmission from an infected mother to the child ranges from 25% to 35%. It can be split into

a)Pregnancy: during pregnancy, chances of transmission through placenta is around 10-15%.

b) During labour: through injuries incurred during labour, HIV transmission may happen with a risk of 65-75%.

c) During breastfeeding: HIV virus is present in breast milk and hence can get transmitted to the infant on breastfeeding (10-15%). Studies have shown that chances are more during initial months of breastfeeding.

4) Through needles: sharing of needles is often practiced by injecting drug users. This can lead to transmission of HIV. Health care personnel also are at the risk of contracting HIV through accidental needle prick injuries and the risk is 0.3%. Blood splash to eyes, mouth or any other mucosal membrane can also lead to HIV infection (0.09%).

Misconceptions of transmission of HIV

Many misconceptions of HIV transmission prevail in the public mind. Sharing food with an HIV infected individual or eating the food cooked by an HIV infected individual will not result in transmission. Neither an expression of love like hugs or shakehands spreads HIV. A number of HIV positive parents take care of their children from the very day they are born and raise them with tender love and care. But we never see HIV transmitted to their children. Hence it is clear that HIV spreads only through earlier mentioned modes.

Insects like mosquitoes or other animals cannot transmit HIV from one person to another. Saliva has very low levels of HIV and hence cannot transmit HIV. But fluids like semen, ascitic fluid (fluid inside the abdominal layers) and breastmilk contain significant levels of HIV and can transmit the infection. Bodily fluids mixed with blood can transmit HIV.

Let us have a look at the stages through which an HIV infected individual passes

Primary infection

HIV starts replicating at a very high rate in the first weeks of its entry into the human body. The infected individuals might experience flu like symptoms such as fever with chills or sore throat. The HIV load in the blood is so high at the initial stage that transmission risk is relatively high.

Asymptomatic phase

The weeks following the primary infection, body starts producing antibodies against HIV and HIV load comes down. The body takes over the virus with its immunity in this phase, but viral multiplication still happens in the body at a low rate. Majority of the HIV infected continue in this stage without any external sign or symptom. This may last for even 5 to 10 years in some individuals. Transmission to others can happen in this stage.

Symptomatic phase

After years of multiplication in the body, at one point, HIV takes over the body’s immunity and symptoms start appearing. The manifestations may range from minor skin conditions to various types of cancer. Majority of the infected individuals detect the disease at the point when they seek medical help. If proper treatment is not taken at this point, even death can happen in a few years’ time.

Signs and symptoms of HIV, tests and diagnosis will be dealt in detail in the next module.