| Spotlight on Steven Meshnick, MD |
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Tropical Infectious Disease Research
In Malawi, 8% of HIV-infected pregnant women are infected with syphilis, even though it is national policy – and very inexpensive - to test and treat all pregnant women for syphilis. The group found that co-infected women are ~3x more likely to transmit HIV to their babies than women with HIV alone. This suggests that syphilis screening and treatment should be incorporated into Prevention of Mother-to-Child Transmission programs. In areas of high malaria transmission, pregnant women and their fetuses can be protected by Intermittent Preventive Therapy (IPT). This involves 2 or more presumptive treatments for malaria during antenatal visits for all women. The current IPT agent – sulfadoxine-pyrimethamine (SP) – is losing efficacy due to resistance. Dr. Meshnick's group has shown that combinations of SP with azithromycin or artesunate are superior to SP alone. Further, The group is currently conducting a CHAVI prospective cohort study to better understand the correlates of mother-to-child transmission in order to direct efforts at vaccine development. In Malawi, SP replaced chloroquine as first-line therapy for malaria in 1993. SP is now failing due to resistance A recent New England Journal of Medicine article suggested that chloroquine-sensitivity may have returned to Malawi and that chloroquine could be re-introduced. However, most malaria infections in sub-Saharan Africa are complex and made up of a mixture of genetically distinct “variants.” Old molecular methods for measuring chloroquine resistance only measure the predominant variant. The group developed a new method to measure minority variant and showed that 25% of Malawians harbored low levels of chloroquine resistant parasites in their blood, suggesting that chloroquine reintroduction might not work. A combination of artesunate and mefloquine is first-line in Thailand and Cambodia. The group developed and validated a new molecular marker for mefloquine resistance (pfmdr1 gene amplification). Two recent clinical studies showed that this combination is failing. Our lab results supported this observation. The Ministry of Health in Cambodia is now using this assay in surveillance for drug resistance. Human African Trypanosomiasis (HAT) is an important but neglected parasitic disease. With support of the Gates Foundation, Rick Tidwell and his collaborators are developing new orally active treatments. But the only data on disease distribution comes from spotty active surveillance. In the future, the group will be attempting to improve surveillance data and develop a plan to insure that infected individuals will have access to the new medications. Click on thePowerPoint slide below for more information on Dr. Meshnick's research.
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| Last updated June 11, 2008 |
The research group led by Dr. Meshnick focuses on infectious diseases of developing countries, and has three areas of interest: malaria and HIV diseases during, drug-resistant malaria, and Human African Trypanosomiasis. This research has and will influence policy and in a variety of areas.
