Researchers believe they have finally traced the genetic history of HIV to a single original source: the city of Kinshasa in the Democratic Republic of Congo during the 1920s.
The discovery was made by a group of international researchers, who took the HIV-1 group M pandemic and reconstructed its genetic history. They found that group M’s common ancestor is “highly likely” to have originated in Kinshasa, where a “perfect storm” cumulated in the AIDS epidemic in the 1980s and 1990s.
Over a dozen cases in which HIV made the jump from primates and apes to humans are known, but only HIV-1 made such a devastating impact.
According to the abstract of the study, which was published in the journal Science on October 3, “Rail and river transport in 1960s Congo, combined with the sexual revolution and changes in health care practices, primed the HIV pandemic. Faria et al. unpick the circumstances surrounding the ascendancy of HIV from its origins before 1920 in chimpanzee hunters in the Cameroon to amplification in Kinshasa.”
The spread of HIV-1 from Kinshasa to the rest of the world was aided by a “perfect storm” of factors over the next few decades, which included urban growth, changes in how the sex trade operated, and strong railroad links. According to the study’s researchers, Kinshasa was one of the best-connected cities in all of Africa by the 1960s, the decade when HIV was carried across the Atlantic to Haiti, and from there to the United States.
The first author of the paper, Oxford University professor Nuno Faria, explained that “data from colonial archives tells us that by the end of [the]1940s over one million people were travelling through Kinshasa on the railways each year.”
Thus, the study concludes, “from those early events, a pandemic was born.”
Senior author Oliver Pybus, a professor at Oxford University’s Department of Zoology, said “For the first time we have analyzed all the available evidence using the latest phylogeographic techniques, which enable us to statistically estimate where a virus comes from. This means we can say with a high degree of certainty where and when the HIV pandemic originated.”
A compilation of genetic data allowed scientists to trace the spread of HIV throughout the Democratic Republic of the Congo (then called the Belgian Congo and Zaire). By the early 1950s, it had reached regional hubs connected to major cities within southern and eastern African countries.
Faria explained, “We think it is likely that the social changes around the independence in 1960 saw the virus ‘break out’ from small groups of infected people to infect the wider population and eventually the world.”
One social change that may have contributed to HIV becoming a full epidemic was, ironically enough, public health initiatives aimed at curbing other diseases. According to the study, they “led to the unsafe use of needles (which) may have contributed to turning HIV into a full-blown epidemic.”
The Democratic Republic of the Congo’s efforts to treat people with known STDs of the day may have involved the use of needles that were not sterilized. Today, infections such as HIV and hepatitis C are relatively common in men over fifty in the DRC.
The research team said that further study is needed to gain a better understanding of how the epidemic spread prior to the identification of HIV in 1981.