Michigan Researcher Reports on the Role of Trace Metals in the Pathogenesis of Malaria

Many parts of the world where malaria is endemic — especially developing countries — are increasingly being contaminated with toxic metals. The consequences of concurrent exposure of human populations to high levels of toxic metals (or suboptimal amounts of essential metals) and malaria parasites were addressed in a recent Strungmann Forum held in Frankfurt, Germany. Co-edited by Dr. Jerome Nriagu, an emeritus professor of environmental health sciences in the University of Michigan’s School of Public Health, and Dr. Eric Skaar from Vanderbilt University’s School of Medicine, the forum’s report provides a comprehensive assessment of the role of trace metals in the pathogenesis of malaria and other infectious diseases.  This report, published in 2015 by Princeton Press, relates to an earlier study by Nriagu and his collaborators of childhood lead poisoning in Nigeria, where malaria is pandemic. Although the study reported a significant association between blood lead levels and malaria infection of children, it was not possible to define the mediating role of lead exposure in host-Plasmodium interaction with specific regards to the influence on the host tolerance or host resistance.

[Photo: Dr. Jerome Nriagu]

Michigan Team Investigates the urbanicity of Malaria Transmission in Malawi

Malaria is associated with the poorest and most underdeveloped parts of the world—so much so that a major determinant of malaria is poverty itself. Within developing countries, however, malaria transmission is heterogeneous: rural areas experience high burdens of infection and mortality while urban areas experience almost no local transmission.

Using Malawi as a test case, a team led by U-M School of Public Health epidemiology professors Dr. Mark L. Wilson and Dr. Joseph Eisenberg and the School of Natural Resources’ adjunct assistant professor Dr. Peter Larson identified factors traditionally associated with malaria, such as proximity to water sources (mosquito breeding locations), as well as factors associated with economic development and social services, like proximity to transportation infrastructure and health services. Ultimately they found that urbanicity varies across the landscape with urban-like environments in traditionally rural areas and rural-like environments even in major city centers.

This new measure was used to better characterize malaria risk along an urbanicity continuum. The researchers discovered that risk did not drop linearly, but instead remained constant for low to mid-level rural environments, then dropped precipitously to eventually reach zero for heavily urbanized areas. Additionally, within politically defined urban areas, rural-like environments exist in which households experience high malaria risk, whereas within politically defined rural areas, there are urban-like environments where risk is quite low. These findings could help improve service delivery by better targeting areas where people live at the greatest risk of infection.

  
[Photo: (left to right) Dr. Mark Wilson, Dr. Joseph Eisenberg, and Dr. Peter Larson]