Health research: forerunner of the AIDS virus tens of thousands of years old. New questions for AIDS research.
(09/17/2010) The precursor of the AIDS virus HIV is older than expected. The original form of the virus must be at least 32,000 years or older, according to American scientists from the "Tulane National Primate Research Center" in Convington. The US scientists were able to identify SI virus strains, the original form of the causative agent of the immunodeficiency disease AIDS, in monkeys on the African island of Bioko. The island separated from the mainland around 10,000 to 12,000 years ago, so that the monkeys have been isolated since then and, according to the researchers, should not have any SIE viruses.
The fact that more than 25 percent of the monkeys examined on the West African island of Bioko nevertheless carried the SI virus (Simian Immunodeficiency Virus) contradicts the previous position of all experts. On the basis of older molecular biological analyzes, they assumed that the pathogen could be a few hundred years old at most. With the help of intensive DNA tests and subsequent computer-calculated models, based on biological experience, the US researchers are now coming to the conclusion published in the current issue of the "Science" science magazine that the SI virus is between 32,000 and 75,000 years old got to.
The scientists argue about the biologist Michael Worobey from the University of Arizona and the virologist Preston Marx from the "Tulane National Primate Research Center" in their age estimation, on the one hand, logically genetic and, on the other, historical-reconstructive. Since the island of Bioko separated from the mainland more than 10,000 years ago, the SI virus must have been widespread in certain species of monkeys even then. The SI viruses now found on Bioko have a different evolutionary history than the SI viruses on the mainland, so that they differ clearly in their DNA. Preston Marx, head of the research group at the Tulane National Primate Research Center, explains that the viral strains of the original peninsula were separated from those of the mainland and subsequently developed independently. Due to the relatively few molecular changes in the SI virus over time, the experts also come to the conclusion that the evolution of the pathogen proceeds far more slowly than previously thought.
The SI virus has apparently been transported in the organism by monkeys for thousands of years, but today, unlike the HI virus, it does not cause AIDS in most infected animals. According to the researchers, the slow molecular evolution of the pathogen probably took millennia before a deadly virus has become a relatively harmless pathogen. According to the US researchers, it could take just as long based on natural molecular evolution for the virulence (ability of the pathogen to trigger a disease) to decrease from HIV.
Based on the knowledge gained, the researchers hope to be able to trace the development of the HI virus. The scientists are faced with the question of how humans could live alongside infected primates suffering from AIDS for thousands of years without the immune deficiency disease also breaking out in them.
Today, more than 33 million people worldwide are infected with HIV. The virus from the retrovirus family triggers the immunodeficiency disease AIDS (acquired immunodeficiency syndrome) after an incubation period of several years, the consequences of which kill about 2 million people annually. So far, there has been no successful treatment, even if many infected people in modern industrialized nations can lead a completely “normal” life due to the relatively effective active ingredients for symptom relief. The spread of the HI virus has become a pandemic in the past 25 years, which according to the organization UNAIDS has cost around 25 million lives so far, with the African continent particularly affected today. (fp)
AIDS: SI virus is considered a precursor to HIV
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