Onesmo ole-MoiYoi
"There are things we can do now," said ole-MoiYoi, who was born in Tanzania. "I hope that new technologies will enable us to develop vaccines, but we don't have to wait. We are watching this disease kill a child every 30 seconds. It's irresponsible to wait."
His vision includes distributing insecticide-impregnated bed nets, using affordable and effective drugs, identifying and treating people who carry the malaria parasite, and working closely with affected communities.
ole-MoiYoi was Director of Research and Partnerships at the International Centre of Insect Physiology and Ecology (ICIPE) until recently and is now a Senior Visiting Scientist there. He shared the preliminary results of an integrated malaria control program, which includes ICIPE research on the ecology and behavior of mosquitoes.
An aggressive campaign against mosquitoes successfully eradicated endemic malaria in the southern United States and in Europe about 60 years ago. "The lesson that has been forgotten from that campaign, in the current pursuit of new drugs and vaccines, is that mosquito control is critical for a successful malaria eradication effort," he said.
A similar campaign against mosquitoes can be safely conducted today in sub-Saharan Africa, where most of the two million annual deaths worldwide from malaria occur, with a targeted combination of approaches to break the transmission cycle and without widespread pesticide use, he asserted.
"The idea is to hit malaria from all angles," ole-MoiYoi said.
ICIPE investigations have revealed unexpected mosquito breeding sites. For example, some officials had attributed malaria outbreaks in the Kenyan highlands exclusively to global warming and higher temperatures, he said. But researchers discovered no apparent increase in average temperatures recorded at tea plantations there over the last 70 years. A closer look revealed a proliferation of water-filled pits for brick-making, driven by an increase in the manufacturing of brick homes.
Malaria outbreaks have occurred in other ecological zones, ole-MoiYoi said. Flooded fields of rice, a new crop for Africa that can yield two harvests a year, have created inadvertently mosquito larvae hatcheries. In other areas, the predominant mosquito breeding sites are manmade - abandoned pools, littered plastics and cans, and blocked water drains.
"It is within our capacity to control malaria by working with communities to minimize mosquito vector breeding sites," said ole-MoiYoi. He suggested that control efforts include adding preparations of the bacteria Bacillus thuringiensis israelensis (Bti) to brick pits and irrigation tanks, he said. Bti is considered a relatively safe biopesticide that destroys the intestines of larval mosquitoes. Another control measure is rotating rice with other crops such as soybeans.
In other studies, ICIPE researchers are investigating the individual body odors that make mosquitoes avoid one person and bite another. A discouraging odor might be as effective as a pesticide, ole-MoiYoi suggested, and possibly safer to use.
Another ICIPE study, already concluded, tested the plant-feeding behavior of mosquitoes and found that infected mosquitoes select certain plants and, by feeding on these plants, appear to become less infectious.
Researchers are also studying genetic factors that underlie malaria transmission. Using inbred mouse strains, some of which are either resistant or, conversely, susceptible to rodent malaria, scientists have narrowed the search for resistance to malaria to a stretch of DNA that corresponds to a section of human chromosome with a large number of immune regulatory molecules, he said.
A webcast of ole-MoiYoi's talk is available. The talk was co-hosted by the HSPH Department of Immunology and Infectious Diseases.
—CCM
Copyright, 2007, President and Fellows of Harvard College
