November 2005
New study finds malaria could play key role in mother-to-child transmission of HIV in pregnancy
Yaoundé, Cameroon (17 November 2005)--Malaria infections boost production of a substance that might significantly increase HIV replication in the placenta. This interaction could explain why mother-to-child transmission (MTCT) of HIV in Yaoundé increases following a rainy season, according to new findings presented at this week's Fourth Multilateral Initiative on Malaria (MIM) Pan-African Malaria Conference.
Laboratory tests have revealed that biological substances known as "proinflammatory cytokines", such as TNF-alpha, which is found in high levels in placentas infected with malaria, could stimulate HIV replication in the placenta.
"Our research highlights the fact that placental malaria, through the placental cytokine network, could play an important role in mother-to-child HIV transmission in utero that has been underestimated so far," said Anfumbom Kfutwah of the Pasteur Center's virology laboratory. (Thursday, 3:10 p.m., Ebony Hall, Parallel Session 26, Presentation 169)
He said scientists have been investigating a possible link between malaria and in utero HIV infections since a study conducted in Yaoundé, Cameroon found that MTCTs peaked three months after the rains peaked. Seasonal rains are known to bring an increase in malaria infections by providing the ideal breeding environment for mosquitoes that carry the disease.
Kfutwah will be discussing a study currently ongoing by scientists at Cameroon's Pasteur Center in collaboration with the Institut Pasteur in Paris, France, on placentas collected from women who were HIV positive and HIV negative, and with and without malaria. This study is investigating the expression of proinflammatory cytokines in relation to both pathogens.
Kfutwah said that further research needs to be done to better understand how the malaria parasite induces the inflammatory response that appears to interfere with the placenta's normal action to protect the fetus from infections.
However, according to Kfutwah, solid evidence of a connection between malaria and risk of fetal infection with HIV could prompt health authorities to consider routinely testing pregnant women in Cameroon and other African countries for both HIV and malaria. Malaria treatment could then be initiated during pregnancy as a way to reduce the risks of infecting the fetus with HIV.
The study by Kfutwah and his colleagues is one of several presentations at the MIM conference that focus on the many challenges arising in a region where co-infections with both HIV, which affects an estimated 29.4 million Africans, and malaria, which sickens 500 million, are unfortunately quite common.
"Each disease by itself is a major problem both for the individuals affected and the health care system," said Andreas Heddini, the MIM Secretariat coordinator. "But the fact that they frequently occur together is a major complicating factor, and we need more research to clarify how the two infections interact and how to best treat co-infection. When you look at the many discussions at MIM, it's clear that African scientists are aware that we cannot look at HIV and malaria in isolation. We must investigate any interactions between what are arguably the two biggest health threats facing the continent today."
Below are descriptions of other MIM presentations investigating issues related to HIV and malaria co-infection: - Modest Mulenga of the Tropical Diseases Research Centre in Zambia will discuss a study on the use of intermittent preventive treatment of malaria with sulfadoxine-pyrimethamine in HIV-positive pregnant Zambian women. The World Health Organization currently recommends the use of intermittent preventive treatment (IPT) to reduce the burden of disease due to malaria during pregnancy. Recent evidence suggests that more frequent monthly dosing may be more effective for HIV-positive pregnant women. (Monday, 4:15 p.m., Bubinga Hall, Parallel Session 1, Presentation 7)
- Stanley Mudambo of Zimbabwe Military Health Services will discuss research looking at the extent to which being HIV positive causes severe complications and poor responses to malaria treatment. (Tuesday, 1:00 p.m., Poster Session 9, Poster 217A)
- Tatfeng Mirabeau of Lahor Public Health and Research Center, Nigeria, will discuss research showing that malaria can have varying affects on people who are HIV positive depending on what is known as their CD4 count, which is a measure of immune system strength. People infected with HIV who had a low CD4 count--and hence a more compromised immune system--had higher levels of parasites in their blood (or parasitemia) compared to those with a higher CD4 count. (Wednesday, 1:00 p.m., Poster Session 7, Poster 131B)
- Noel Chisaka of WHO-AFRO's Southern Africa Inter-Country Malaria Control Program will report on an analysis of malaria and HIV co-infection in Southern Africa that calls for stronger collaboration between HIV and malaria programs. The study notes that current treatment strategies for both diseases are failing to adequately respond to issues that arise due to interactions between HIV and malaria. (Tuesday, 1:00 p.m., Poster Session 9, Poster 226A)
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To provide coordinated international approach to fighting malaria, the Roll Back Malaria Partnership (RBM) (www.rollbackmalaria.org) was launched in 1998 by the World Health Organization, the United Nations Children's Fund (UNICEF), the United Nations Development Programme (UNDP) and the World Bank. The Partnership now brings together governments of countries affected by malaria, their bilateral and multilateral development partners, the private sector, non-governmental and community-based organizations, foundations, and research and academic institutions around the common goal of halving the global burden of malaria by 2010. World Malaria Report 2005 http://rbm.who.int/wmr2005/
The Multilateral Initiative on Malaria (MIM) (www.mim.su.se), launched in Dakar, Senegal in 1997, is an international alliance of organizations and individuals seeking to maximize the impact of scientific research against malaria in Africa to ensure that research findings yield practical health benefits. The MIM Secretariat was previously hosted for 3-years terms by the Wellcome Trust (UK) and the Fogarty International Center at the National Institutes of Health (US). In 2003, the Secretariat moved to Stockholm, Sweden, where it is hosted by the Karolinska Institute and Stockholm University.
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