SEATTLE, Dec. 7 /PRNewswire/ -- Malaria may be fueling the spread of
HIV in areas of sub-Saharan Africa where there is a substantial overlap
between the two diseases, while HIV may be playing a role in boosting adult
malaria-infection rates in some parts of the region, according to a new
study by researchers at Fred Hutchinson Cancer Research Center and the
University of Washington.
The findings, published in the Dec. 8 issue of Science, found that
because malaria increases the viral load of an HIV-infected person on the
order of 10 times, it makes HIV more transmissible to a sex partner.
Conversely, HIV may play a role in the geographic expansion of malaria in
Africa because HIV-infected persons are more susceptible to malaria
infections due to their already-compromised immune systems, according to
study co-authored by Laith J. Abu-Raddad, Ph.D., Padmaja Patnaik, Ph.D. and
James G. Kublin M.D., M.P.H.
"While HIV/AIDS is predominantly spreading through sexual intercourse,
this biological co-factor induced by malaria has contributed considerably
to the spread of HIV by increasing HIV transmission probability per sexual
act," said Abu-Raddad, an HIV/AIDS research scientist in the Hutchinson
Center's Statistical Center for HIV/AIDS Research and Prevention and the
Center for Studies in Demography and Ecology at the University of
Washington.
"In turn, the weakening of the immune system by HIV infection has
fueled a rise in adult malaria-infection rates and may have facilitated the
expansion of malaria in Africa," said Kublin, an HIV/AIDS scientist in the
Hutchinson Center's Clinical Research Division.
Using a mathematical model designed by Abu-Raddad that was based on HIV
and malaria co-infection data in Malawi measured and collected by Kublin,
the scientists for the first time were able to assess quantitatively the
impact of malaria on HIV and vice versa, as well as provide the first
assessment of the role of "blips" in HIV viral load seen during HIV
co-infection with some other diseases. They estimate that tens of thousands
of HIV infections and millions of malaria cases are likely the result of
this co-infection.
Using the town of Kisumu, Kenya on the shore of Lake Victoria as an
example, Abu-Raddad estimates that 5 percent of all HIV infections are
attributed to the heightened HIV viral load induced by malaria. "In Kisumu,
we estimate that 10 percent of adult malaria episodes are attributed to
HIV," he said.
That translates into 8,500 excess HIV infections and 980,000 excess
malaria episodes since 1980 in a town with an adult population of about
200,000, the researchers said.
Kublin said that these findings suggest that other co-infections such
as genital herpes or tuberculosis may have also contributed to the rapid
expansion of HIV in Africa.
The study's findings have implications for public health, Kublin said.
"We can reduce HIV/AIDS transmission by concomitantly treating HIV/AIDS co-
infections with malaria as well as other diseases," he said.
"The global public-health system's failure to deal with the challenge
of HIV/AIDS contributes directly to its failure to tackle other
public-health challenges such as malaria and tuberculosis," Abu-Raddad
said. "As long as HIV/AIDS continues to spread, it will aggravate the
difficulties we face with these other diseases and may contribute to the
emergence of more lethal or drug-resistant strains of these infections,"
Kublin added.
The study was funded by the Center for AIDS Research (CFAR) at the
University of Washington through the Mathematical Modeling Program for
HIV/STD Research. The HIV Vaccine Trials Network at Fred Hutchinson Cancer
Research Center provided partial support for this work.
About Fred Hutchinson Cancer Research Center -- The Hutchinson Center's
interdisciplinary teams of world-renowned scientists and humanitarians work
together to prevent, diagnose and treat cancer, HIV/AIDS and other
diseases. Center researchers, including three Nobel laureates, bring a
relentless pursuit and passion for health, knowledge and hope to their work
and to the world. For more information, please visit fhcrc.org.
CONTACT: Dean Forbes, +1-206-667-2896, or dforbes@fhcrc.org
SOURCE Fred Hutchinson Cancer Research Center
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CONTACT:
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