HIV

By Sahar Sattarzadeh

Of all the discoveries one can make, this particular one has to be near the top of the list. As if there weren’t so many new discoveries about HIV already, here comes another to stir up more research and questions in science and medicine. It has been found that the human immunodeficiency virus (HIV) that causes AIDS has existed in human populations for at least seventy years, which is much longer than researchers had thought. This fact has been revealed as a result of the of the world's fastest computer at the Los Alamos National Laboratory, located in San Francisco.

It was speculated that the AIDS virus jumped a species, infecting chimpanzees then humans. New evidence that shows that it jumped from chimpanzees to humans around 1930 is beneficial to the advance of medicine. The fact that HIV existed among humans earlier than expected could provide epidemiologists with helpful hints about the future evolution of the epidemic. These hints may lead to the production of an AIDS vaccine.

This recent discovery also gives evidence of the innocence of researchers who were blamed in the past for allowing the virus to spread to humans. In the 1950's, a group of researchers were testing a polio vaccine in Africa. In the book The River, written by British science writer Edward Hooper, these researchers were targeted by the claim that the AIDS epidemic started when researchers used chimpanzee cells contaminated by the virus to produce the vaccine. This is definitely not the case, according to geneticist Bette Korber of Los Alamos. Los Alamos is the major research facility for the study of the HIV virus. This facility is where all the genetic sequence information on HIV is generated throughout the world. Once a scientist determines the sequence of a new variant of the AIDS virus, it is sent to Los Alamos for comparison to other viral sequences and for preservation for use in future studies.

Korber assured the seventh “Conference on Retroviruses and Opportunistic Infections” that the virus emerged long before such experiments began. She came to her concluson as a result of a comparison of the genetic material of the many current strains of the virus, used for extrapolation to predict their common origin. The method Korber used in reaching her results was not unusual. Her approach involved a well-recognized technique, which has been used to determine when different species diverged from a common ancestor.

The oldest known blood sample containing HIV dates from 1959, so some scientists and researchers are confident that the virus entered the population a few years before then. However, others believe that the virus was most likely present in human populations for many years, possibly even decades. According to Korber's study, it appears that the latter view seems to be the case.

As a result of the HIV’s ability to mutate very rapidly, a growing number of variants of the virus are now infecting human results. This rapid mutation rate is responsible for the easy resistance HIV develops when it comes into contact with anti-AIDS drugs. Therefore, it becomes much more difficult to create vaccines against the disease. So far, there are now eight major subtypes of HIV-1, which is the most common form of the virus circulating around the world, and has a much larger number of strains that vary only slightly from one another. HIV-1 is known to have originated in chimpanzees because of close sequence similarities to a chimpanzee virus. HIV-2, a less common form, is known to have originated in sooty mangabey monkeys. Since comparing all this data was no simple task, an extremely powerful computer was needed to compare all the HIV-1 sequences in order to search for a common ancestor. This is where "Nirvana" comes in; it is the world's most powerful computer, and it is held at the Los Alamos National Laboratory. Nirvana is able to perform more than one trillion calculations per second.

"They didn't give me [the entire computer], but they did give me 512 nodes," which was the equivalent of running her computations on 512 computers at the same time," Korber said. Using the computer to examine all those different sequences, Korber tried to determine the common ancestor of HIV. After using two statistical techniques, she estimated when the virus first appeared. In both cases, she reached the same conclusion: the virus jumped from chimpanzees to humans at sometime around 1930.

This may be one piece to the enormous puzzle, yet how the virus jumped species is still an open question. Some researchers suspect that the jump occurred as a result of humans trapping or eating chimpanzees. Historian Bruce Fetter, of the University of Wisconsin at Milwaukee, notes that the French colonial government used forced labor for massive infrastructure projects, such as the construction of the Congo-Ocean railway between 1921 and 1934 in what was then called the French Congo. More than 20,000 workers died from mostly malnutrition during this project, Fetter said, and it’s likely that the workers who survived could have been driven by hunger to trapping and eating chimps, Fetter said. As a result, the first outbreaks of HIV were seen in this region thirty years later. Many people of the era trapped chimps for use in circuses and scientific research. This trapping ultimately brought humans and primates into closer contact.

Despite the many ways in which HIV jumped to humans, it still has not yet been discovered which one is completely accurate. However, this news still sheds light for us all.

According to Dr. Harold Jaffe of the Centers for Disease Control and Prevention, these findings are " a lesson for the future. If we continue to interact with primates, there is a potential for other non-human viruses to enter the population as well."