HIV has been raging for hundreds of years

HIV raged from earlier than the scientific world.Photo: SPL.

The emergence of sub-Saharan cities in Africa in the early 20th century triggered the spread of AIDS-causing viruses. This virus appeared on Earth much earlier than the scientific world.

Acquired immunodeficiency syndrome (AIDS) was first discovered in 1981 in the United States, but the disease actually lived with humans for decades.

In a newly published study, University of Arizona (US) experts found the ancestor of an HIV strain caused the majority of AIDS in a blood sample taken from a person in Kinshasa (Democratic Republic of Congo). in 1959. Back then, Kinshasa was a Belgian colony known as Leopoldville.

In 2008, the team found the origin of another HIV strain in a blood sample that a patient at Kinshasa took in 1960. After analyzing genetic differences between the two strains of the virus and calculating how long it took for those This difference appears, experts say, they most likely have the same ancestor and began to split into two strains at least 50 years ago.

"This is the first time we have the opportunity to compare two relatively long-lasting HIV strains. That helps us determine their rate of evolution, the time when they infect humans, the factors that make them become a scary pathogen in humans, "said Dr. Michael Worobey, lead researcher.

Genetic analyzes show that HIV appeared between 1884 and 1924, the period when cities grew like mushrooms in Africa. Scientists believe that the ancestor of HIV is a virus that only lives on chimpanzees in Africa. The virus then jumps to some people when they kill and eat chimpanzees. Many people are infected with the virus that way, but they account for too small a rate so for a long time, HIV has a very low infection rate.

But the massive development of cities in Africa has changed that. The concentration of people in urban areas has brought more opportunities for HIV infection. In addition, the virus received tremendous support from the explosion of prostitution in cities in the early years of the 20th century.

"The change in population density and urban lifestyle has enabled HIV to expand worldwide," concluded Dr. Michael Worobey. Experts claim that it is not unusual for HIV to be detected after 70 years of living with humans, because it takes several years for symptoms of the newly developed disease. "Time lag" is too large to make the role of virus less noticeable.

Professor Paul Clark, an expert in evolutionary history at the University of Edinburgh (UK), said that the University of Arizona's discovery could help experts identify the evolution of HIV. According to him, HIV-1, the virus that causes 95% of today's AIDS cases, may have first appeared in the Congo capital.