Preventing Malaria, Part 2

by National Institute of Health

(Page 5 of 5)

Mosquito Control

The appearance and spread of insecticide-resistant mosquitoes, as well as stricter environmental regulations, now limit the effectiveness of the insecticide DDT, the mainstay of the 1950s and 1960s malaria eradication programs. More recently, researchers have found that mosquito netting soaked with other insecticides, which prevent mosquitoes from making contact with humans, significantly reduce malaria transmission. Therefore, as part of its Roll Back Malaria program, WHO is promoting widespread use of mosquito netting in endemic areas. Still, in some parts of Western Africa, mosquitoes have become resistant to the pyrethroid insecticide used to treat mosquito netting. Although scientists do not think this is a serious limitation yet, it points out the need to continue research to identify new tools for mosquito control.

Vaccines

Research studies conducted in the 1960s and 1970s showed that experimental vaccination of people with attenuated malaria parasites can effectively immunize them against getting another malaria infection. Current methods to develop vaccines based on weakened or killed malaria parasites are technically difficult and do not readily lend themselves to commercialization. Therefore, much of the research on vaccines has focused on identifying specific components or antigens of the malaria parasite that can stimulate protective immunity.

In 1997, the National Institute of Allergy and Infectious Diseases (NIAID) launched a 10-year Research Plan for Malaria Vaccine Development based on four cornerstones.

Establishing a resource center to provide scientists worldwide with well-characterized research reagents. Increasing support for discovery of new vaccine candidates. Increasing capacity to produce vaccine candidates at the quality and quantity that will be required for clinical trials. Establishing research and training centers in endemic areas where potential vaccines may undergo clinical trials.

Under these and other programs, scientists are conducting research to understand the nature of protective immunity in humans and how to induce protective immune responses with malaria antigens.

Genome Sequencing

Genome sequencing, the process that allows scientists to determine an organism's genetic blueprint, is accelerating the discovery of new targets for drugs, vaccines, and diagnostic tests for malaria and other infectious diseases. By examining those blueprints, researchers can determine the genes that control a broad range of an organism's biological properties, such as feeding, reproducing, and adapting to its environment.

The complete genome sequences for the Anopheles mosquito and the P. falciparum parasite were published in 2002. Researchers are sequencing other Plasmodium species. These advances mark a milestone in malaria research. Combined with the recently completed human genome sequence, scientists have the complete genetic blueprints for the malaria parasite and both of its animal hosts. Researchers are now using that information to learn more about how Plasmodium survives within people and mosquitoes, and to discover new ways to diagnose, prevent, and treat the disease.

The conquest of malaria is a top priority for many international and government organizations, philanthropic foundations, and research institutions. In 2001, the NIAID published the Global Health Research Plan for HIV/AIDS, Malaria, and Tuberculosis. That plan highlighted the serious toll exacted by malaria and reinforced its position as one of the three biggest infectious global health problems. As the lessons of the past decades have so convincingly demonstrated, however, conquering malaria is difficult. No one anticipates a quick victory even if new malaria drugs hit the market or a vaccine proves highly successful. Rather, researchers and health planners expect their best chances lie in a many-sided attack, drawing upon a variety of weapons suited to local environments. Skillfully combining several approaches, both old and new, may at last make it possible to outmaneuver the persistent and deadly parasites.

As with all diseases of worldwide importance, a critical aspect of our future ability to control malaria will depend on the skills and expertise of scientists, health care providers, and public health specialists working in endemic regions. Therefore, strengthening the research capability of scientists in these areas is another major focus of these efforts. NIAID works closely with national and international organizations involved in malaria research and control. The Institute was also a founding member of the Multilateral Initiative on Malaria, which emphasizes strengthening research capacity in Africa.

About the Author

NIH is the nation's medical research agency - making important medical discoveries that improve health and save lives. The National Institutes of Health (NIH), a part of the U.S. Department of Health and Human Services, is the primary Federal agency for conducting and supporting medical research.