HIV:
Did starving Congo workers introduce it seventy years ago? Med Times Copyright, All Rights Reserved, 2004-2005
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."