Everything you need to know about human immunodeficiency virus and aids. Some of the frequently asked questions are as follows:-
Q.1. How and when was HIV discovered?
Ans:.By 1992, two cancer research laboratories were involved in research to find out the cause of a new disease, later called Acquired Immune Deficiency Syndrome (AIDS). In 1993, research teams headed by Luc Montagnier and Robert C. Gallo in Pasteur Institute, Paris and National Cancer institute, USA, respectively, published reports hinting that they have found the cause of AIDS.
The virus was referred to as HTLV-III (human T-cell lymphotropic virus) / LAV (lymphoadenopathy associated virus) by the scientific community. The name was finally changed to Human Immunodeficiency Virus (HIV) in 1986. A new strain of HIV was identified in 1985, referred to as HIV-2 relatively common in West Africa. It appeared relatively milder than HIV-1.
Q.2. How did the HIV virus originate?
Ans. Origin of virus is not yet certain. Evidence suggest that it existed in chimpanzees in West Africa and then infected humans possibly through a bite or scratch from a chimpanzee and from there it may have spread into a wider population.
Q.3. What is AIDS?
Ans. AIDS is primarily a disease of the immune system characterized by the severe depression of the immune system and the acquisition of life-threatening secondary infections. It is caused by the Human Immunodeficiency Virus (HIV).
Q.4. When were cases of HIV reported in India?
Ans. No country has been left unscathed by HIV including India. First cases of HIV infection were reported in sex workers in Tamil Nadu, India in 1986. In 1987 a National AIDS Control Programme was launched to deal with the crisis by surveillance, blood screening, and health education.
By the end of 1987, out of 52,907 who had been tested, around 135 people were found to be HIV positive and 14 had AIDS. The infection rates continued to rise and in 1992 the government set up NACO (National AIDS Control Organization). Its functions were formulation of policies, prevention work and control programmes to combat the HIV and AIDS. HIV had now extensively spread in the country.
Q.5. What is HIV?
Ans. HIV stands for Human Immunodeficiency Virus. Like all viruses, HIV cannot grow or reproduce on its own. In order to make new copies of itself it must infect the cells of a living organism. It belongs to the class Retroviruses and family Ientiviridae. On the basis of geographical distribution, biological and molecular characterization and extent of transmissibility, two types of HIV are recognized- HIV1 and HIV2.
Q.6. What does HIV consist of?
Ans. HIV is 120 nm icosahedral, enveloped viruses which stores its genetic information as ribonucleic acid (RNA). RNA must be converted to DNA by a special enzyme reverse transcriptase. The outer envelope of virus consists of a lipid bilayer with 72 spikes or knobs of gp 120 and gp 41. The protein core inside the envelope contains two copies of RNA and the virus enzymes reverse transcriptase, integrate and protease which are essential for viral replication and maturation.
Q.7. How does HIV hide from the immune system?
Ans. The virus can hide within the cytoplasm or integrate into the infected cell’s genetic material. Protected from the immune system, HIV can lie dormant in an infected cell for a long time, sometimes for years. These cells serve as a latent reservoir of the virus.
Q.8. What are the routes of transmission for HIV?
Ans. The HIV can transmit by following routes:
1. Un-protective sexual inter-course:
Whether heterologous or homologous, is a major route of transmission.
2. Blood borne infection:
Use of HIV-infected blood, transplanted organs or tissues, improperly sterilized needles and syringes that have been in contact with infected blood is an efficient way of transmission.
3. Mother to child:
HIV can transmit from an HIV-infected woman to her foetus or infant before, during, or after birth.
Q.9. What are the common opportunistic infections in AIDS?
Ans. Almost 80% of patients with AIDS die from infections other than human immunodeficiency virus (HIV). These infections usually occur late in the course of disease when CD4 T-cell count has fallen below 200 cells per cubic milliliter. Most of these infections are caused by organisms that do not normally afflict healthy individuals and are thus considered to be opportunistic.
Common important pathogens are:
Mycobacterium tuberculosis, Candida albicans, Pneumocystis carinii (usually non-invasive pathogens), Cryptosporidium parvum (invades the cells but remains localized in the gut), Toxoplasma gondii (penetrates through the gut to cause systemic infection), Cytomegalovirus and Herpes simplex virus.
Q.10. What Bio-safety measures should be taken in laboratories while handling HIV-infected samples?
Ans. There is no vaccine for prevention of HIV/AIDS; treatment is expensive and not easily available. Therefore, prevention of infection is important in health care settings. Universal precautions should be taken while handling samples in laboratory.
These include:
Barrier protection like use of gloves, laboratory gowns, facial masks and protective glasses Frequent and thorough hand washing.
Safe techniques including use of biological safety cabinet class 2
Safe handling of sharp items and safe disposal of used sharps in puncture-proof containers
Safe handling of specimen
Safe techniques including mechanical pipetting device.