HIV, HUMAN, GORILLA - CAMEROON: NEW LINEAGE

Date: 3 Aug 2009
Source: BBC News [edited]
<http://news.bbc.co.uk/1/hi/health/8175379.stm>


Scientists find new strain of HIV
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Infections of SIV [simian immunodeficiency virus] among gorillas seem
quite low. Gorillas have been found, for the 1st time, to be a source
of HIV [human immunodeficiency virus]. Previous research had shown
the HIV-1 strain, the main source of human infections, with 33
million cases worldwide, originated from a virus in chimpanzees.

But researchers have now discovered an HIV infection in a Cameroonian
woman which is clearly linked to a gorilla strain, Nature Medicine
[Nature Medicine Volume 15 No 7. 2009] reports. A researcher told the
BBC that, though it was a new type of HIV, current drugs might still
help combat its effects. "There's no reason to believe this virus
will present any new problems, as it were, that we don't already face."

Although HIV/AIDS was 1st recognised by scientists in the 1980s, it
is thought to have 1st entered the human population early in the 20th
century in the region of the Democratic Republic of Congo. The virus
probably originally jumped into humans after people came into contact
with infected bush meat. SIV viruses have been reported in other
primates, including gorillas.

French doctors treating a 62-year-old Cameroonian woman who was
living in Paris said they initially spotted some discrepancies in
routine viral load tests. Further analysis of the HIV strain she was
infected with showed it was more closely related to SIV from gorillas
than HIV from humans. She is the only person known to be infected
with the new strain, but the researchers expect to find other cases.

Before moving to Paris, she had lived in a semi-urban area of
Cameroon and had no contact with gorillas or bush meat, suggesting
she caught the virus from someone else who was carrying the gorilla
strain. Analysis of the virus in the laboratory has confirmed that it
can replicate in human cells. Co-author Dr David Robertson, from the
University of Manchester, said it was the 1st definitive transfer of
HIV seen from a source other than a chimpanzee, and highlighted the
need to monitor for the emergence of new strains. "This demonstrates
that HIV evolution is an ongoing process. The virus can jump from
species to species, from primate to primate, and that includes us;
pathogens have been with us for millions of years and routinely
switch host species. The fact the patient had been diagnosed in
France showed how human mobility can rapidly transfer a virus from
one area of the world to another."

Speaking to the BBC's Wold Today programme, Dr Robertson said there
was no reason to believe that existing drugs would not work on the
new virus. "If some day we do manage to develop a vaccine, there's no
reason to believe it wouldn't work," he said.

Professor Paul Sharp, from the University of Edinburgh, said the
virus probably initially transferred from chimpanzees to gorillas. He
said the latest finding was interesting but perhaps not surprising.
"The medical implication is that, because this virus is not very
closely related to the other 3 HIV-1 groups, it is not detected by
conventional tests. So the virus could be cryptically spreading in
the population." However, he said that he would guess it would not
spread widely and become a major problem. "Although the patient with
this virus was not ill, there is no reason to believe that it will
not lead to AIDS," he added.