Figures from the World Health Organization (WHO) show that 35 million people worldwide have HIV, or human immunodeficiency virus. However, the origin of the sexually transmitted virus, which causes AIDS (acquired immunodeficiency syndrome), is not clear although scientists believe that variations of the virus were transmitted from monkeys and chimps to humans in Africa.
Now, a new research suggests that the strain known as HIV-1 Group M, which is attributed to the current global pandemic, has its roots in Kinshasa, the capital city of the Democratic Republic of the Congo (DRC) in the early 1920s.
For the new study published in the journal Science on Oct. 3, Philippe Lemey, from Belgium's University of Leuven, and colleagues analyzed the archived samples of the genetic code of the virus to trace its roots and when it emerged. They also compared their findings with historical data and found evidence that the early spread of the virus from Kinshasa followed certain patterns.
The researchers' analysis showed that the railway network in Kinsasha made it as one of the best connected cities, a factor that contributed to the spread of the virus. Lemey said that the genetic data showed that the virus quickly spread across the country as infected individuals travelled through railways and even waterways.
"Using statistical approaches applied to HIV-1 sequence data from central Africa, we show that from the 1920s Kinshasa (in what is now the Democratic Republic of Congo) was the focus of early transmission and the source of pre-1960 pandemic viruses elsewhere," the researchers wrote.
Changing sexual habits and unsafe medical practices also appeared to have contributed to the spread of the virus. The researchers found that the changing behavior of sex workers and the unsafe use of needles by health practitioners who treat these workers may have contributed to HIV becoming a full-blown pandemic.
"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," said study researcher Nuno Faria, from Oxford University.
Lemey said that the virus remained undetected for some time because only a few were infected at first. The symptoms caused by infection, which is marked by the weakening of the body's immune system, are not also new to Africa. AIDS was only recognized in 1981 but by then it has already spread to most parts of the globe.
