HIV / AIDS Timeline with an Emphasis on Australia &
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HIV/AIDS INFORMATION LINE 150 - 154 Albion Street Surry Hills NSW 2010 Tel: +61 (2) 9332 9700 Freecall: 1800 451 600 A HIV/AIDS TIMELINE Emphasising the Australian / New South Wales Perspective The Origins of HIV/AIDS It is generally agreed that Simian Immunodeficiency Virus (SIV) found in African primates became Human Immunodeficiency Virus (HIV) which causes Acquired Immune Deficiency Syndrome (AIDS). Genotyping research, comparing different types of HIV with different types of SIV, suggests that HIV has been introduced to humans on at least 12 different occasions, once each for the 12 different types of HIV-1 and HIV-2 discovered so far. HIV-1 is divided into 4 types - Groups M (main), O (outlier), N (new or non-M/O) and P. HIV-1 Group M, is by far the most easily transmitted and widespread form of HIV found today, being responsible for more than 99% of all HIV infections worldwide and it is the form of HIV usually intended when this document just refers to HIV. HIV-1 Group M is also further divided into 9 further subtypes or clades and there are also 48 recognised recombinant forms (made up of a mix from the genome of 2 or more of the 9 clades which are most likely the result of superinfection of individuals with multiple subtypes). Countries or risk groups can have different dominant subtypes. HIV-1 Groups O, N and P only occur in small numbers of people and are rare outside of Africa. HIV-2 has 8 subtypes, 2 of the subtypes are common and are called Group A and B. The 6 additional subtypes, Groups C-H, have so far only been found in one person each. HIV-2 is more difficult to transmit, is less deadly and is generally found in older people living in West Africa, where HIV-2 has been shown to be associated with treatment by injection for tuberculosis, trypanosomiasis and sleeping sickness and with some rituals that allow the transfer of blood. The incidence of HIV-2 is falling and it has been theorised that it may eventually naturally die out. It will probably never be known exactly how, when and where HIV was transmitted to humans, but the current general consensus is: How: The Natural Transfer Theory (also Hunter, or Bushmeat, Theory) is considered by most who work in HIV research to be the simplest and most plausible explanation for the cross-species transmission of HIV, whereby researchers propose SIV was transferred to humans who hunted primates for ‘bushmeat’ via bites, cuts or other skin damage coming into contact with blood during hunting or butchering. Monkey herpes B virus, simian foamy virus and monkeypox are examples of other simian viruses that are common in people who handle monkeys and apes. Exactly how SIV evolved into HIV following infection of a hunter or bushmeat handler is still a matter of debate, although natural selection would favour any virus capable of adjusting so that it could live in, infect and reproduce using, the cells of a human host. Interestingly, the SIV most closely related to HIV-1 Group M, is itself a blend of 2 SIVs, the 1st found in red-capped mangabeys and the 2nd found in 3 other monkey species. All are monkeys that chimps hunt and eat, and the date for the transfer to, or the combination of these viruses in, chimps is estimated to be only a few hundred years before HIV was transferred to humans. When: There are many estimates of exactly when the various strains of HIV have been transferred to humans. The fact that centuries of trade in millions of African slaves introduced parasitic and viral diseases to the Caribbean and Americas did not result in an epidemic of HIV, suggests that HIV did not exist, or was extremely rare, in humans prior to the 1880s. Hunting chimpanzees, which are big and agile, became much easier with the introduction of guns, which until the 20th century were almost entirely in European hands. The most accepted estimate for the year that HIV-1 Group M was transferred to humans is considered to be around 1921 (with a margin for error of 1908-1933). Natural Transfer Theory adherents suggest that HIV was limited to very small numbers of people (less than 100) until an infected individual from the Cameroon area migrated to, or visited, the densely populated twin cities of Kinshasa/Brazzaville in the Belgian and French Congo, where other factors (discussed below) then drove expanded transmission and diversification. The estimates for the next 4 most common HIV types/groups that are transmissible between humans are: HIV-2 Group A transferred around 1932 (1906- 1955), HIV-2 Group B transferred around 1935 (1907-1961), HIV-1 Group O transferred around the year 1920 (1890-1940) and HIV-1 Group N transferred around 1963 (1948-1977). Where: Current research suggests that HIV-1 Group M, was transferred from chimpanzees to humans somewhere in what is now the Republic of Cameroon, near the borders of the Gabonese Republic and the Democratic Republic of Congo. Current research suggests that HIV-2, which is mostly restricted to West Africa, was transferred to humans from a related, but different, strain of SIV found in sooty mangabey monkeys somewhere in or around the Republic of Guinea-Bissau (type A) and the Republic of Côte d'Ivoire (Ivory Coast) (type B). It seems the other HIV subtypes were transferred at different places and times, but in similar ways from various primates, with, for example, evidence currently suggesting that HIV-1 Group O and P are more closely related to forms of SIV found in gorillas. There are other theories and factors that most likely contributed to the early and continued spread of HIV, such as: • Contaminated Needle Theory. Until the 1950s there was extensive reuse of glass syringes for immunisation against, and treatment of, many diseases in Africa. After 1956, disposable plastic syringes became available but are likely to still have been reused due to cost. In both cases, inadequately sterilised or un-sterilised equipment probably contributed to the spread of HIV from small groups where it existed for a long time into the general population. In colonial Africa, treatment of the native population was carried out for humanitarian reasons, but also to protect the native workforce and colonial administrators. Some patients are reported to have been given 300 or more injections during the colonial period. A number of studies by Dr Jacques Pépin (see October 2011) looking at elderly Africans showed large numbers with Hepatitis B & C and HTLV-1 (all blood borne viruses like HIV) and also other pathogens that are likely to have been transmitted by contaminated injecting equipment. A Facility of Prince of Wales Hospital South Eastern Sydney Local Health District - 2 - • Colonialism Theory (sometimes known as the Heart of Darkness Theory) whereby it is suggested that during the late 19th and early 20th century, when much of Africa was ruled by European colonial forces, colonial rule was particularly harsh and many people were forced into crowded labour camps and cities where people from distant tribes mixed, food was scarce (making bushmeat attractive), sanitation was poor and physical demands extreme. Colonial policy encouraged the migration of men, and discouraged the migration of women and children, to camps and cities. This led to a gender imbalance where sex work by women was tolerated or encouraged in order to keep male labourers happy. For example, in Kinshasa in 1955, there were 5.4 single men for every single woman. • Industrialisation and Urbanisation. The move of people from relatively sparse rural populations towards much more densely populated centres following industrialisation certainly increases the opportunities for risk contacts for many diseases including HIV. In Central Africa for example in 1931, only 5% of the population lived in cities. In the largest city, Kinshasa, the migration driven population went from 40,000 (1931) to 220,000 (1951) then to more than 500,000 (by 1961) when this represented a third of the entire population of the Belgian Congo. • Sexual Liberation. In the western world during the 1960s and 1970s the traditional attitudes and codes of behaviour relating to sexuality and interpersonal relationships underwent significant change. This included an increased acceptance of sex outside of traditional monogamous relationships. This may have been partially influenced by the availability of the contraceptive pill which substantially reduced the risk of pregnancy and may have led to a decrease in the heterosexual use of condoms and an increase in Sexually Transmitted Infections (STIs). In Central Africa, where HIV originated and STIs were common, sex work became de- stigmatised, as it was a way for women to gain independence and control over their own lives. In late 1950’s Kinshasa, 10% of women may have been involved in the sex trade, with an estimated 50 sex workers for every 1000 adult males. • Travel. Increased availability, affordability, popularity and speed of both national and international travel by rail, motor vehicle, ship and aeroplane over the 20th century has no doubt contributed to the spread of many infectious diseases like HIV. • Intravenous drug use. Non-medical injection of drugs grew during the 20th century. Initially the preferred route of injection by drug users was subcutaneous injection. Then between the First and Second World Wars, and especially post Vietnam, intravenous injection slowly became the preferred method. When non-medical access to injecting equipment was scarce, sharing of equipment was common. • The blood industry. The discovery of blood groups in 1901 paved the way for blood transfusion (introduced 1940s-1950s in Africa).