Lautze’s Dams of Malaria in East Africa
School of Engineering student Jonathan Lautze uses research from his university studies to construct a way to reduce the transmission of malaria through water resource engineering and management.
Medford/Somerville, Mass. [02.28.08] Worldwide malaria kills more than a million people a year. Ninety percent of these deaths occur in Africa, mostly among young children. Jonathan Lautze is researching how to curb the transmission of malaria through water resource engineering and management- research he pursued while completing Tufts School of Engineering's first doctoral degree in conjunction with the interdisciplinary Water: Systems, Science, and Society certificate program. By controlling a dam's reservoir water levels, the development of malaria-carrying mosquito larvae can be disrupted
Lautze says his research is part of an integrated strategy needed to address the spread of malaria hotspots, the control of malaria transmission and the subsequent malaria treatment if the first prongs of attack fail.
"Malaria is increasing in Africa and you need a bundle of measures to deal with it," says Lautze. "If you were trying to decide the answer to 'How do you best to control malaria?' in a multiple choice question, you'd want another letter to say 'All of the above.'"
"Jonathan's work exemplifies the need for an interdisciplinary partnership between engineers and public health experts and other stakeholders," says Paul Kirshen, director of the WSSS program. "A health crisis like malaria must be informed by engineering research, and engineers must understand the far-reaching, public health impact of their constructions."
Malaria is classified as a water-borne disease even though people don't contract it through drinking water and ingesting parasites like giardia and cholera. The single-celled malaria parasite is transmitted through the saliva of a vector-the Anopheles mosquito-whose lifecycle is dependent on the presence of water.
"Mosquitoes are highly sophisticated and different species of mosquitoes have different preferred breeding habitats," Lautze said, including water pools created from rainfall, water storage tanks, or the shorelines of dam reservoirs. Adult female mosquitoes lay up to 200 eggs in water where the larvae take between one and two weeks to develop. After reaching adulthood, the winged, blood-suckers take flight looking for a source of nourishment in the form of blood.
If the mosquitoes don't encounter bed nets, chemical sprays, such as DDT, or the slap of a human hand, they may fly on to feed on people infected with malaria. Inside the human host, the malaria parasite evades the immune system, infecting the liver and red blood cells, and develops into a form mosquitoes acquire when having a blood meal. Once inside the mosquito, the parasite takes as little as 10 days to mature until it can infect a new human host who continues the cycle.
To study malaria transmission in Africa, Lautze headed to the Koka Dam, located on the Awash River in the Ethiopian Rift Valley, 60 miles southeast of the capital, Addis Ababa. Lautze chose Koka because of the strong health data collected in the area. He sifted through eight years of malaria case data from malaria control centers surrounding the Koka reservoir.
In the data collected from 1994-2002, Lautze found that the geographic distance of a village cluster, called a kebele, from the Koka reservoir shoreline correlated with malaria transmission, with rates about 2.3 times greater for villages located less than three kilometers (about 1.8 miles) from the reservoir compared to those located six to nine kilometers farther away. Lautze also correlated reservoir water levels with fieldwork along the shoreline to determine prevalence of mosquito larvae. Lautze says, the reservoir shoreline continues to be the most important breeding habitat for any kebele surrounding the reservoir. His data points to the conclusion that lowering reservoir levels faster than half a meter over a month results in fewer mature mosquito larvae and therefore reduced malaria transmission.
Though Lautze's research is robust and straightforward, he says carrying out his recommendations may not happen immediately.
"The point between publishing this data and implementing this is several years," he says. "When you build a dam and have a reservoir, you know there's going to be some tradeoffs because you're going to have competing objectives,"-and not only among the water resource management group. Lautze says the disconnect between the water and public health sector often creates barriers to devising the best approach to control malaria. But given global warming, all competing interests are running out of time.
"In warmer temperatures the larvae will develop and transform into adults more rapidly than in colder temperatures," says Lautze. With increased temperatures in Ethiopia and elsewhere, transmission rates will only increase and malaria control will become increasingly complex.
In the meantime, Lautze continues his work with water management in Africa through the World Bank. He also has a graduate student carrying on the water resource management research he began through WSSS. "Water resource people will continue to construct dams," Lautze says. "Health affects may still be an unintended consequence, but this is a good lever that can be pulled to reduce disease transmission."
Profile written by Julia Keller, Communications Specialist, Tufts School of Engineering