World Malaria Day Event Explores Why a Preventable and Treatable Illness Still Kills in Great Numbers

Recent discoveries relating to the biology of malaria and successes with the drug artemisinin have buoyed optimism about controlling the illness, but does a call for eradication set too-high expectations? And is the current passion for distributing mosquito-repelling bed nets the best use of resources? In commemoration of World Malaria Day on April 23, the Global Infectious Disease Program (GID) at the Harvard Initiative for Global Health (HIGH) hosted a talk and networking reception for researchers and students from around the University, highlighting these and other issues in the fight against the disease. A number of HSPH researchers spoke at the event.

Malaria Is a Preventable Killer

Malaria is preventable and treatable, but it kills up to 3 million people every year and affects roughly 500 million. It is endemic in 101 countries, hitting hardest in sub-Saharan Africa. Scientists’ understanding of the disease has progressed rapidly following the sequencing of the human, mosquito, and malaria parasite genomes, with researchers now able to trace the parasite’s path of invasion into the host; however, there is still no vaccine.

Distribution of the drug artemisinin and insecticide-treated bed nets have had some positive results, but it is too early for complacent optimism, said Manoj Duraisingh, assistant professor of immunology and infectious diseases at HSPH, in a presentation on the biology of the disease. “Even with the best interventions, 40 percent of malaria patients presenting with severe malaria still die,” he said.

During the World Health Organization’s malaria eradication campaign of 1955-1978, it was widely believed that the drug chloroquine and the pesticide DDT would wipe out the disease, Duraisingh said. But the effort was ultimately abandoned due to “widespread resistance to available insecticides, wars and massive population movements, difficulties in obtaining sustained funding from donor countries, and lack of community participation,” according to the WHO’s web site. Today, even more people are dying of malaria and drug resistance is on the rise.

“Last time, we thought we had the tools and stopped developing new ones,” Duraisingh said, adding that control of the disease is likely a more realistic goal than complete eradication.

Given the poverty of the countries in which malaria is endemic, the agenda of how to fight the disease has long been set by outside interests such as corporations and non-governmental agencies. In the first half of the 20th century, corporations working in malaria-prone areas sought to keep their work forces healthy by using mainly environmental management techniques such as drainage, said Marcia Castro, assistant professor of demography in the Department of Global Health and Population and associate faculty of the Harvard University Center for the Environment, in a presentation on corporate responsibility and malaria control.

Although these methods proved effective, few people received training to keep them up following the initial perceived success of the WHO eradication campaign. Today, environmental management ranks low in the priorities of interventions for malaria control. Favored instead are the use of bed nets and indoor residual spraying, which are not always the most appropriate combination of interventions, Castro said. She argued that more evidence needs to be gathered about what is the best integrated package of interventions tailored to each area.

Economic Impact

Günther Fink, assistant professor of international health economics at the Department of Global Health and Population, agreed in his presentation on the economic impact of the disease. The anti-malaria program currently implemented in Zambia appears to have significantly reduced malaria infections in Zambia. The exact magnitude of these declines is however hard to quantify due to the increased use of diagnostic tools and the resulting adjustment of official statistics. From a macro-economic perspective, Fink argued that the often-quoted statistic that malaria has slowed economic growth in Africa by 1.3 percent per year over the last 30 years is likely an overestimate due to other omitted factors in the empirical model. Although the disease’s short-run economic impact on individuals is important from a social perspective, the  economic consequences of malaria can be felt more strongly in  the long term through the effects of malaria induced child fevers and anemia on cognitive development and human capital formation.

Fink is currently studying the effects of malaria in the modern Sub-Saharan African setting of Accra, Ghana. The study aims at exploring coping mechanisms at the household levels and to quantify the number of days individuals are out of work or school because of their own or somebody else’s sickness in the household. The study also analyzes where individuals seek treatment, how diseases are diagnosed and which medication is chosen.

President Barack Obama recently joined the conversation on malaria, stating that the United States would work to help meet the United Nations’ goal to end malaria deaths by 2015.

Dyann Wirth is the Richard Pearson Strong Professor of Infectious Diseases, chair of the Department of Immunology and Infectious Diseases, director of the Harvard Malaria Initiative at HSPH, and co-director of the GID Program at HIGH. She closed the event, noting that this is an exciting time to be a malaria investigator.

More information about the GID Program at HIGH is available online.

--Amy Roeder.