AIDS

AIDS (Acquired Immune Deficiency Syndrome) is one of the most serious communicable diseases of present time. It is a viral disease that hampers the immune system of human body. Thus, the patients suffering from AIDS become unable to defend themselves against infections.

Occurrence: AIDS is a widely distributed human disease found throughout the world. AIDS was first described in 1981AD. In the year 1985, it was postulated that AIDS might have originated in Africa as the AIDS virus was endemic among African green monkeys. Probably, the virus was transmitted to man by eating uncooked brain of green monkeys.

AIDS is spreading very fast to various countries of the world and is threatening to be a global epidemic. It has been estimated that about 3-3.5 million people are infected with this disease in various parts of the world. Out of these, about 2 million patients of AIDS are in the USA alone. In Nepal, the first case of AIDS was reported in 1988 and now there are about 50,000 patients in Nepal.

Causative Organism: The causative agent of AIDS is a virus that disrupts the immune system.       This virus was first identified in 1983 by a French physician Dr. L. Montagnier in the lymph node of a male homosexual. He named it LAV ( Lymphadenopathy-associated virus). Later, an American scientist Dr. Robert Gallo isolated an almost identical virus which he termed as 'Human T-cell lymphotrophic virus' (HTLV-III). In May 1986, the name HIV was given to this virus by "International committee on Taxonomy of Viruses". Since then, it is known as HIV, which stands for human immuno-deficiency virus.

 HIV is a retrovirus, which means that it contains RNA as its genetic complement. It has two strands of RNA that form the template for DNA when acted on by the enzyme reverse transcriptase. The resulting DNA has seven genes that code for the formation of new viruses after infection.

 Reservoir and Source of Infection: Infected persons serve as the reservoir of HIV, which may be an AIDs patient or a carrier (HIV positive). The source of infection is the blood and tissue fluid of the infected body.

Modes of Transmission: The virus get transferred from individual to individual by any of the following way,

·         Sexual Contact: HIV is found in semen and vaginal fluid of an AIDS patient. It may be transmitted during intimate sexual contact involving an exchange of body fluids. Most of the reported cases of AIDS are sexually transmitted.

·         Blood and Blood Products: Transfusion of HIV contaminated blood and blood products can infect the recipient.                        

·         Contaminated Equipments: The virus is also readily transmitted during intravenous injection with contaminated needles; AIDS is prevalent among users of illegal drugs. An unsterilized skin piercing instrument (like, ear piercing or tattooing needles) can spread the disease from one person to another.

·         Mother to Child: A woman infected with HIV may spread the disease to foetus through blood circulation and to child through breast feeding.

        Incubation Period: Incubation period is variable ranging from 6 months up to 10                  years or more.

Viral Action: When the virus enters the blood stream, the body's immune system recognizes it as an antigen. First, the phagocyte engulfs it but is unable to destroy the virus. A type   of T cell called a T4 cell then attacks the virus, but the virus enters the T4 cells unharmed. At the same time antibodies made by the B cells also attack the viruses in the blood but the viruses remain unharmed by antibody activity. The virus may remain dormant for up to 10 years in the T4 cells. However, at some point, the virus undergoes reproduction and creates many new viruses inside the T4 cells. As these viruses are released, they infect additional T4 cells and eventually destroy the capacity of the T4 cells to fight diseases. Once the T4 cells are destroyed, the immune system cannot fight diseases. People infected with HIV virus then become susceptible to pathogens to which they normally would be immune. Most individuals with full grown AIDS die within three years.

Symptoms: Most individuals, infected with HIV have no symptoms of the disease and feel well at the time of infection. In some cases, few symptoms appear during early days of infections like mild fever, tiredness and loss of appetite.

This is followed by no further impacts for months or years. Sometimes, before the end of the incubation period, the patients develop a complex of different disorders which are called as ARC (AIDS - related complex).

ARC - Symptoms:

·         Unexplained diarrhoea for more than a month.

·         Malaise, fatigue, fever for more than a month.

·         Continuous weight loss

·         Night sweats

·         Swollen lymph glands (Lymphadenopathy and splenomegaly)

·         Certain lymph nodes especially that of groin, neck or axilla may enlarge.

As the disease progresses, people gradually lose all natural defence mechanism. Finally, the immune system collapses and never recovers. This is the last stage of the disease during which certain complex symptoms are seen, like:

·         Kaposi's sarcoma, a skin cancer like condition.

·         Pneumonia

·         Recurrent skin infections

·         Cryptococcal meningitis

·         Blindness, due to the inflammation of retina of eye.

·         Damage of nervous system and death.

Diagnosis: The diagnosis of AIDS is made by blood test. This technique of identifying the HIV antibodies in the blood is called ELISA - test (Enzyme linked immuno - sorbent Assay).

Control Methods: There is no cure and no vaccine for AIDS yet available At present, prevention is the only answer to check the further spread of the disease in the community.

 Preventive Methods: The following important measures will help to minimize the spread of the disease:

·         Public awareness by providing the information about AIDS.

·         To avoid unsafe sexual contacts, for which condoms may be used.

·         To avoid multiple partners and homosexuality.

·         Screening before blood transfusion.

·         Rehabilitation of drug addicts.

·         Use of disposable syringe and needles.

·         Infected women should avoid pregnancy.

·         Early diagnosis and treatment of other sexually transmitted diseases.

         Treatment: AIDS is still considered as a fatal and incurable disease due to lack of proper medicines. But so far, the scientists have developed certain antiviral drugs that may suppress the growth and development of HIV inside the patient’s body. Thus, these drugs help to prolong the life span and the quality of life of an AIDS-patient. These drugs are AZT (azidothymidine), Ribavarian, DDI (Dideoxyinosine) and Zaicitabine. An antiparasitic drug, Sumarin has been reported to check the activity of reverse transcriptase.

AIDS is not transmitted by: HIV is a virus which does not survive easily outside the body. It is not spread by:

·         Casual contact at work or school.

·         Touching, hugging or shaking hands.

·         Sharing bathrooms or toilets.

·         Kitchen and eating utensils.

·         Personal items, like combs and towels.

·         Talking, sneezing or coughing.

·         Mosquitoes and other insects.

·         Food and beverages.

Thus, it becomes clear that there is no danger of becoming infected through general social contacts.