HIV

Discovered by : Luc Montagnier

Discovered in year : 1983

HIV stand for Human Immunodeficiency Virus which belongs to Retroviridae Family and Lentivirus Genus. It is a Virus that causes Acquired Immunodeficiency Syndrome also known as AIDS, a condition in humans in which the immune system begins to fail, leading to life-threatening opportunistic infections. HIV infection occurs by the transfer of blood, semen, vaginal fluid, pre-ejaculate, or breast milk. Within these bodily fluids, HIV is present as both free virus particles and virus within infected immune cells. The four major routes of transmission are unsafe sex, contaminated needles, breast milk, and transmission from an infected mother to her baby at birth (Vertical transmission). HIV infection in humans has been declared pandemic by the World Health Organization (WHO). HIV primarily infects vital cells in the human immune system such as helper T cells (specifically CD4+ T cells), macrophages, and dendritic cells. HIV infection leads to low levels of CD4+ T cells through three main mechanisms: firstly, direct viral killing of infected cells; secondly, increased rates of apoptosis in infected cells; and thirdly, killing of infected CD4+ T cells by CD8 cytotoxic lymphocytes that recognize infected cells. When CD4+ T cell numbers decline below a critical level, cell-mediated immunity is lost, and the body becomes progressively more susceptible to opportunistic infections.

Four Stages of HIV infection

1. Incubation Period - The initial incubation period upon infection is asymptomatic and usually lasts between two and four weeks
2. Acute Infection - The second stage, acute infection, which lasts an average of 28 days and can include symptoms such as fever, lymphadenopathy (swollen lymph nodes), pharyngitis (sore throat), rash, myalgia (muscle pain), malaise, and mouth and esophageal sores.
3. Latency Stage - The latency stage, which occurs third, shows few or no symptoms and can last anywhere from two weeks to twenty years and beyond.
4. AIDS -  AIDS, the fourth and final stage of HIV infection shows as symptoms of various opportunistic infections.

History - The two types of HIV virus are believed to have originated in West-Central Africa and jumped species (zoonosis) from a non-human primate to humans. HIV-1 is thought to have originated in southern Cameroon after jumping from wild chimpanzees  to humans during the twentieth century. It evolved from a Simian Immunodeficiency Virus (SIVcpz). HIV-2, may have originated from the Sooty Mangabey (Cercocebus atys), an Old World monkey of Guinea-Bissau, Gabon, and Cameroon. HIV is considered to have originated in non-human primates in sub-Saharan Africa and transferred to humans early in the 20th century. The first paper recognizing a pattern of opportunistic infections was published on June 4, 1981.

Between late 1980 and early 1981, a group of five men showed symptoms of Pneumocystis carinii pneumonia (PCP), a rare oppourtinistic infection that was known to present itself in people with very compromised immune systems. Soon, another set of men developed a rare skin cancer called Kaposi’s sarcoma (KP). Many more cases of PCP and KP quickly emerged, alerting U.S. Centers for Disease Control and Prevention (CDC). A CDC task force was formed to monitored the outbreak. After recognizing a pattern of anomalous symptoms presenting themselves in patients, the task force named the condition acquired immune deficiency syndrome (AIDS).

In 1983, two separate research groups lead by Robert Gallo and Luc Montagnier independently declared that a novel retrovirus may have been infecting AIDS patients and published their findings in the same issue of the journal Science

Robet Galo's Discovery - Galo and his team had isolated a virus from an AIDS patient. This virus was strikingly similar in shape to other human T-lymphotropic viruses (HLTVs). Gallo's team called their newly isolated virus HLTV-III.

Luc Montagnier's Discovery -  At the same time, Montagnier's team also isolated a virus from a patient. This virus showed symptoms of  lymphadenopathy (swelling of the lymph nodes) of the neck and physical weakness. These symptoms were two classic symptoms of AIDS.  According to Montagnier and his team, the core proteins of this virus were immunologically different from those of HTLV-I.  Montagnier's group named their isolated virus lymphadenopathy-associated virus (LAV).

However, Montagnier along with his colleague Françoise Barré-Sinoussi, were awarded one half of the 2008 Nobel Prize in Physiology or Medicine for his 'Discovery of human immunodeficiency virus'. Harald zur Hausen also shared the Prize for his discovery that human papilloma virus leads to cervical cancer, but Gallo was left out. Gallo was disappointed as he was not named a co-recipient. And Montagnier was surprised that Gallo was not recognized by the Nobel Committee. According to him Gallo had a very important role in proving that HIV caused AIDS

Development in the Discovery of HIV

In 2009,  a new strain of HIV was discovered in a 62-year-old woman from Cameroon. She was diagnosed with HIV in 2004, but as of August 2009 showed no signs of AIDS. The new strain was designated HIV-1 group P. It has been derived from gorillas. It is most similar to a strain of simian immunodeficiency virus known as SIVgor that was first isolated from western lowland gorillas in 2006. The discovery of the new strain has been taken as evidence that gorillas and not only chimpanzees, are likely sources for HIV.

Role of Discovery of HIV in the improvement of Human Life

• Screening of blood products for HIV has largely eliminated transmission through blood transfusions or infected blood products in the developed world.

• Awareness of HIV also led to limiting it's spread to a certain extent.

• Discovery of HIV also enabled it's limited treatment with anti-retrovirals. This increases the life expectancy of people infected with HIV to more than 5 years as of 2005. Without antiretroviral therapy, patients with AIDS typically die within a year.