Tiny insects, from mosquitos to sand flies, spread diseases that annually kill and sicken millions of people and animals worldwide.
Kenneth Linthicum is one of the nation’s leading experts on insects and disease prevention, having invented a successful surveillance system that predicts the onset of the mosquito-borne Rift Valley fever in Africa and the Middle East that devastates domestic livestock and causes human illness. He also developed techniques that have protected U.S. military personnel overseas from debilitating afflictions caused by sand flies.
“His work has provided the research findings needed to protect literally millions of people from disease and to save agriculture billions of dollars,” said Steven Kappes, a deputy administrator of the U.S. Department of Agriculture’s (USDA) Agricultural Research Service.
Edward Knipling, administrator of the Agriculture Research Service, said Linthicum, the director of the USDA Center for Medical, Agricultural and Veterinary Entomology, has done seminal work forecasting “how and when new diseases could come, and how we could deal with those diseases.”
“His research predicting Rift Valley fever has been heralded as a scientific and humanitarian achievement,” said Knipling.
Rift Valley fever is an acute viral disease that kills or sickens humans and domestic animals, such as cattle, sheep, goats and camels. It is most commonly associated with mosquito-borne epidemics during years of unusually heavy rainfall.
Working with scientists at NASA’s Goddard Space Flight Center, Linthicum developed a model that uses global climate data and vegetation changes to predict conditions that will lead to floods. Flooding causes mosquito eggs to hatch in the soil, leading to the emergence of the virus in adult mosquitoes and the spread of the disease.
Before this technique was developed, there was no way of knowing when an outbreak would occur. Today, Linthicum’s predictive data provides governments and international organizations with early notice and an opportunity to deploy resources appropriately.
“We now use data to give countries three to five months to prepare and mitigate disease transmission,” Linthicum said. “We also share risk information with the Centers for Disease Control and Prevention and the Department of Defense (DOD) that have personnel in these areas.”
In the Horn of Africa in 1997, before Linthicum’s predictive method was developed, there were 100,000 human cases of Rift Valley fever and an estimated $100 million in economic losses in Kenya alone due to the devastation of livestock. In 2006-2007, when Linthicum’s model was first used to predict an outbreak, only 1,000 human cases were reported in the same region, and the economic loss was down to $65 million.
Linthicum also made a major contribution by helping halt the spread of leishmaniasis, a debilitating and sometimes deadly disease spread by sand flies that adversely affects the liver and pancreas and causes fever, severe weight loss, fatigue and anemia.
The disease affects some 12 million people worldwide, according to the World Health Organization, and struck hundreds of soldiers in Iraq who developed red bumps on their skin that swelled for weeks before rupturing into oozing wounds. It also has been a problem for American troops in Afghanistan.
“There was little the military could do to control the insects or stop the biting from occurring,” said Linthicum.
Linthicum and his team, along with the DOD, developed new approaches for pesticide applications, including treating the camouflage netting troops use in the field with an effective insecticide.
“We saw a very significant reduction in sand flies that could bite our deployed troops,” Linthicum said.
Linthicum found a study area in the deserts of California where temperatures get nearly as high as they do in Iraq and conducted trials over four years.
“Ken looked at different residual insecticides and devices that worked under different conditions and sought to combine them for a method that would work in Iraq-like conditions,” said Daniel Strickman, a national program leader in the Agricultural Research Service,
“He basically invented a new way to treat camouflage netting. The plastic absorbs the insecticides and remains active for a year or more,” said Strickman. He said Linthicum’s work has resulted in the military now being “far ahead in what to do” to protect the troops.
“There is no question that when the history of the 21st-century medical and veterinary entomology is written, Ken Linthicum’s achievements and clear thought will be discussed in detail,” said Kappes.