|AIDS||Acquired Immuno Deficiency Syndrome|
AIDS is caused by theretrovirus called Human Immunodeficiency Virus(HIV) of Lentivirus family.
There are two genetic but antigenically different variants of HIV noted among AIDS patients.
AIDS also occur in other species such as
HIV transmission occurs broadly through exchange of blood or body fluids contaminated by the virus or virus-infected cells.
Sexual transmission is responsible for more than 75% of all cases of HIV transmission and especially heterosexual transmission accounts for most infections. Transmission among intravenous drug abusers occurs through shared needles, syringes etc… contaminated with HIV. About 1% of all AIDS cases in infants results from vertical transmission of virus from infected mother to the fetus or newborn. Mother-to-infant vertical transmission occurs in three modes
HIV cannot transmit through normal day-to-day personal contacts and there is no evidence of infection through insect bites.
|Structure of HIV||
HIV-1 virion is spherical in shape. The virus core contains:
Capsid protein or p24 is the most readily detected viral antigen and is therefore the target for the antibodies used to diagnose HIV infection in blood screening. Extreme variability in antigen structure poses a formidable barrier for vaccine development.
Initial stage symptoms include fever, headache, sore throat, and swollen lymph nodes.
Symptoms post clinical latency include swollen lymph nodes, fever, diarrhea, weight loss, and fatigue.
HIV is a retrovirus, which has the ability to reproduce by synthesizing DNA from the RNA genome. It mainly infects immune system and CNS.
Infection and progression of virus occurs through following stages,
an impaired immune system).
Two types of diagnosis are common, which includes screening a blood sample for the presence of antibodies against the virus.
There is no cure for AIDS. The drugs are expensive and causes serious side effects. All contemporary drugs can either slow or stop viral replication but cannot inactivate all viral particles, which makes eradication impossible.
Also the problem of the rapid mutation rate exacerbates the situation to formulate a vaccine for the virus.
Antiviral therapy effectively reduces mother-to-child transmission, but only 5 percent of women receive this therapy.
Reverse transcriptase inhibitors:
Reverse transcriptase inhibitor drugs work by inhibiting the enzyme and halting the life cycle of the virus.
e.g. Azidothymidine(AZT) was the first drug approved for treating HIV infection.
Protease inhibitor drugs work by interfering with a viral protein called HIV protease. Without this protein the viral particles cannot assemble properly and become inert.
Fusion inhibitors inhibit the viruses from fusing with the host cell membranes and stops the replication of virus.
Highly Active Antiretroviral Therapy(HAART) uses Cocktail drugs(a combination of three or more drugs with different mechanisms of action) to overcome potential resistance. HIV mutates very rapidly and quickly becomes resistant to a once-effective drug.
Around 95% of HIV infections are recorded in developing countries.
AIDS is the fifth major cause of death in adults between the ages of 25 and 44.
Africa alone carries more than 50% of the HIV patients.
Around 90 percent of the children infected with HIV belong to sub-Saharan Africa.
Injected drug use.
Refusal of men to wear a condom during sex.
Govt. has setup State AIDS bodies in 25 states and 7 union territories in 1992.
India’s first National AIDS Control Programme NACP-I was launched in 1992
National AIDS Control Organization (NACO) was put into operation.
The National AIDS Committee was formed in the Ministry of Health and Family Welfare.