THURSDAY, Dec. 20, 2001 (HealthDayNews) -- Dirty needles can spread HIV, the virus that causes AIDS, but an intriguing new theory holds that unsterile needles also may have played a role in how the AIDS epidemic first began.
Researchers, outlining the theory this month in The Lancet, say people involved in mass injections in the 1950s may have unwittingly been involved in a mutation sequence that would decimate Africa over the next half a century.
HIV, or human immunodeficiency virus, generally is believed to have originated from SIV, or simian immunodeficiency virus, which is harbored in monkeys and apes. One of the great mysteries surrounding HIV is how it managed to survive in humans. "SIV is not a human pathogen. It cannot survive in humans," says Ernest Drucker, lead author of The Lancet article and professor of epidemiology and social medicine at Montefiore Medical Center and Albert Einstein College of Medicine, in New York City.
When humans are exposed to the simian virus (for example, a hunter who is bitten by one of the wild animals), their immune systems kill SIV within about a week, probably without any visible symptoms. In fact, SIV probably has been infecting humans for millennia without humans ever actually getting sick, Drucker says.
How then did SIV cross over into humans in a relatively brief time to cause the devastating AIDS pandemic? Previous explanations have ranged from nuclear fall-out to the polio vaccine, but none have been substantiated. Now Drucker and his colleagues say the answer lies with the massive use of modern, unsterile hypodermic needles.
Drucker calculates that SIV needs to complete roughly six to 12 mutations to become HIV, and it just doesn't live long enough in humans to go through the necessary changes. If, however, a person infected with SIV got an injection, and some of that person's blood was transferred to another human via a dirty needle, there might be time for one mutation. If the second person's blood was then transferred to a third person, another mutation might have occurred, and so on in a process referred to as "serial passage." Drucker says, "The basic idea is that unsterile injecting moves partially mutated viruses."
As it happens, hypodermic needles were relatively rare in Africa (and the rest of the world) until after World War II. When penicillin and other injectable antibiotics became widely available at that time, the demand for syringes shot up. These devices, which had once been hand-crafted by artisans, were mass produced in factories at a fraction of the original cost.
Thanks to the wonders of penicillin and other antibiotics, by the 1950s Africans apparently came to expect injections every time they visited a doctor or a clinic. The 1950s also saw the first United Nations-sponsored mass injection campaign to eradicate yaws, a highly contagious, tropical bacterial disease that can destroy bone. It's is a cousin of syphilis.
"There were 35 million injections, and they didn't clean the needles adequately," says Drucker. One of the earliest AIDS cases dates back to Zaire in 1959. The yaws campaign took place between 1952 and 1957.
It's a tough theory to prove. "I think it would be difficult to ever conclusively say that this is the way HIV was spread," says Dr. Sandro Cinti, a lecturer in the division of infectious diseases at the University of Michigan and at the Department of Veterans Affairs Medical Center, both in Ann Arbor.
Drucker and his colleagues are now doing studies to determine how long HIV survives in needles. They also are collecting used syringes and blood samples in areas of Africa where SIV and HIV are common to see if they can find any traces of transitional SIV/HIV.
Any new findings won't help treat people already infected with HIV, but they might help with prevention. Unsterile injections are still widespread in Africa. Authors of The Lancet report say as recently as 1998, the World Health Organization recommended re-use of syringes up to 200 times with sterilization procedures that even WHO admitted were not usually followed. "This [mutation] process is still working. As people continue to get exposed to monkeys, we have a factory for creating new strains of HIV, which can wreck havoc with attempts to develop a vaccine," says Drucker. It can also spread the HIV virus.
The theory also may have a cross-over effect by helping to identify where other illnesses such as Ebola come from. "There will be a clue there as to how viruses jump from one species to another," says Cinti. "That has an impact."
Drucker says, "That an unintended consequence of the introduction of penicillin should be to launch the AIDS epidemic is terrible. African people believe that HIV was caused by white men, and it turns out they're right."
What To Do
For more information on AIDS in Africa, visit The Africa-America Institute or UNAIDS
For more information on HIV prevention, visit the Centers for Disease Control and Prevention.
For more on yaws, check this site.
