Research / Discovery

Vaccine research key to preventing spread of infectious diseases, improving global health

May 25, 2009

Colorado State University has received a $100,000 Grand Challenges Explorations grant from the Bill and Melinda Gates Foundation for an initial year of research. The grant will support an innovative global health research project to develop a vaccine system that attacks the saliva of sand flies to prevent them from spreading infectious diseases like leishmaniasis.

Highly competitive grant

The project, led by William Wheat, Richard Titus and John Spencer, all researchers in the Department of Microbiology, Immunology and Pathology, is one of 81 grants announced by the Gates Foundation in the second funding round of Grand Challenges Explorations, an initiative to help scientists around the world explore bold and largely unproven ways to improve health in developing countries. The grants were provided to scientists in 17 countries on six continents.

To receive funding, Wheat, Titus and Spencer showed in a two-page application how their idea falls outside current scientific paradigms and might lead to significant advances in global health. The initiative is highly competitive, receiving more than 3,000 proposals in this round.

Saliva of sand flies

The research will focus on a compound found in the saliva of sand flies called maxadilan. Research overseen by Titus has recently shown that maxadilan amplifies the impact of parasites that cause leishmaniasis. The microscopic parasites are passed to a victim through sand fly saliva. Leishmaniasis is a disfiguring skin disease and, in some cases, may be fatal.

Researchers know that if a host is injected with a needle filled with the parasites that cause leischmaniasis, they would need to use thousands more of the parasites to mimic the transmission of the disease caused by a single sand fly bite to a host, according to Wheat. That led to the discovery of how maxadilan plays a key role in amplifying the impact of the parasites on the host - it makes the presence of saliva mixed with the parasites - present in an actual bite, much more serious than the parasites alone

Concept applicable to other disease

Although maxadilan exists only in sand flies, the concept that saliva plays an important role in the spread of infectious diseases carried by insects is likely applicable to other diseases such as West Nile Virus, the plague, Dengue fever, malaria and other insect-borne diseases. If CSU researchers can discover a way to turn off the effect of saliva in an infectious insect bite, the knowledge could be widely applied to help develop a cheap vaccine.

The vaccine could be given to humans for protection, making them resistant to maxadilan and other saliva-borne amplifiers, or to animals, which would indirectly protect humans. Animals can spread disease because they often serve as mixing vessels and carriers for insect-borne diseases. Sand flies also accumulate around domestic animals and livestock congregating near humans.

Leishmaniasis is particularly problematic in Afghanistan, Iraq, Mexico and regions near the equator; sand flies exist in the United States in Florida and extreme south Texas.

Life-saving breakthroughs sought

"The winners of these grants are doing truly exciting and innovative work," said Dr. Tachi Yamada, president of the Gates Foundation's Global Health Program. "I'm optimistic that some of these exploratory projects will lead to life-saving breakthroughs for people in the world's poorest countries."

Grand Challenges Explorations is a five-year, $100 million initiative of the Gates Foundation to promote innovation in global health. The program uses an agile, streamlined grant process - applications are limited to two pages, and preliminary data are not required. Proposals are reviewed and selected by a committee of foundation staff and external experts, and grant decisions are made within approximately three months of the close of the funding round.

Applications for the next round of Grand Challenges Explorations are being accepted through May 28, 2009. Grant application instructions, including the list of topic areas in which proposals are currently being accepted, are available at

Contact: Dell Rae Moellenberg
Phone: (970) 491-6009