Nahmias' 14-year-old HIV
finding gains peer acceptance
The virtues of patience and persistence in scientific endeavor have never
been more evident than in the case of Andre Nahmias, director of the Division
of Pediatric Infectious Diseases, Epidemiology and Immunology at the School
of Medicine. In 1984 Nahmias determined that a single blood plasma sample
collected by scientists in Africa 38 years ago contained the HIV-1 virus.
That sample has now been authenticated by molecular testing to be the earliest
known case of HIV-1 infection in the world. This finding pushes the historical
beginnings of AIDS in humans back to the late 1940s or 1950s-at least 10
years earlier than scientists previously believed.
Nahmias is co-author of an article in the Feb. 5 issue of Nature with
David Ho, a physician-researcher at New York's Aaron Diamond AIDS Research
Center. He also collaborated on a study describing the findings presented
at the nation's largest annual AIDS research meeting, held last week in
Chicago.
The blood sample is from an adult Bantu male who died in Leopoldville,
Belgian Congo (Kinshasa in the present-day Democratic Republic of Congo)
in 1959. It was part of a group of more than 2,000 blood samples collected
by U.S. scientists studying genetic blood factors among different African
populations. In 1984 Nahmias, who was the Emory scientist responsible for
first identifying the virus that causes genital herpes, was studying genetic
differences in herpes. He found out about the African samples, which had
been sent to Atlanta.
He decided to examine the samples using then-new serological tests developed
to identify the AIDS virus. After evaluating every sample, he found just
one positive for HIV-1, and his results were confirmed at Duke, Harvard
and the CDC.
Nahmias reported his findings at the "AIDS in Africa" conference
in 1985 and again in a report in the British medical journal The Lancet
in 1986. "At the time, there were a lot of nonbelievers who denied
the importance of the sample, and political factors contributed to people
ignoring the work or finding fault in the methodologies, although five separate
tests were used," Nahmias recalled.
But the 1989 discovery of polymerase chain reaction (PCR), a very sensitive
method of detecting the presence of small amounts of DNA, helped prove Nahmias'
hypothesis. When Nahmias shared his sample with Ho and his colleagues, they
found the sample to be closely related to viral subtypes in a certain group
of HIV-1 viruses that are predominant in today's global epidemic. The sample
predates the virus' mutation into the many varieties existent today and
strongly suggests HIV spread from a single transmission to humans from animals
in the late 1940s or 1950s.
The new information will undoubtedly lead to further research about the
origins of HIV in humans and about how the virus mutated and spread so rapidly
from Africa to Haiti and to the United States, Europe and beyond. Knowledge
about how the virus evolved should help scientists as they search for effective
vaccines for AIDS and try to identify the animal source of viral transmission
to humans.
The HIV discovery is not the first time Nahmias' scientific patience
has been tested. Although he first identified the genital herpes virus in
1965, his team had to wait 17 years for technology to catch up and allow
them to develop the first serological test that distinguishes between non-genital
and genital herpes antibodies. His application of this new test in the past
15 years has helped researchers gain much understanding about the prevalence
of herpes virus in the United States and 25 other countries.
The test was used to establish a link between genital herpes and HIV,
and Nahmias helped the CDC determine that a group of gay men in San Francisco
who had been infected with genital herpes developed HIV more readily.
"What we learned from the African blood sample study is that it
took about 30 years for the {AIDS} epidemic, mostly heterosexually spread,
to take off to high rates in Zaire. The 1989-1994 National Health Survey
indicates that young white Americans are acquiring a primarily heterosexually
transmitted infection-genital herpes-in growing numbers, and recent CDC
data indicate increasing rates of heterosexually transmitted HIV infections
in young Americans. These old and new findings, including the more recent-and
primarily heterosexually transmitted-HIV-1 epidemic in Southeast Asia, provide
another call for greater education and concern in preventing this form of
transmission in our country."
Last September Nahmias received the prestigious Bristol Award from the
Infectious Diseases Society of America in recognition of his career contributions
in infectious diseases. He still saves thousands of samples, including isolates
of herpes simplex virus from all body sites, because, as he explained, "We
don't yet know what questions the future may bring that may be answered
by these frozen samples."
-Holly Korschun
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