Scientists at the University of California, Davis, are
researching how to terminate some of humanity's deadliest
foes -- disease-carrying mosquitoes.


In particular, the dengue virus, spread by mosquitoes, wreaks
havoc with the public heath in tropical regions of the world.
Epidemics are common in Southeast Asia. Dengue fever is an
emerging public health threat in many South and Central
American countries.


Thomas Scott, professor in the Department of Entomology and
director of the Mosquito Research Laboratory, is currently
developing DNA techniques to evaluate the risk of dengue
outbreaks in certain communities. An article in the April 18
issue of the journal Nature profiled Scott's research in
Thailand.


There he found that a dengue-carrying female mosquito may
need many blood meals to reproduce successfully, compared
with the single blood meal required by most other mosquitoes.
This finding, confirmed by individually marking female
mosquitoes and recapturing them around people's homes, sheds
light on why dengue can persist even when very few mosquitoes
are present. It also reveals that just a few infected
mosquitoes or people are needed to jumpstart an outbreak.


Scott is developing techniques to evaluate the risk of dengue
outbreaks in specific communities. Using DNA fingerprinting,
he has been able to match the blood in captured mosquitoes'
stomachs to DNA samples from villagers.


He is now using this technique to discover which segment of
the population mosquitoes bite, how frequently, and how far
they roam in search of a meal.


In another project in Peru, Scott's team is studying the
connection between the dynamics of dengue transmission to the
density of mosquito populations. Basic research such as this,
he hopes, may provide clues that will allow public-health
officials to predict an imminent outbreak.


"Our hope is that we can identify some fundamental principles
that can be tested elsewhere," he said. "Predicting an
epidemic before it happens might not help to stop it, but it
could help health departments prepare to treat the youngest
and most susceptible victims, and so prevent unnecessary
deaths."


Additional Media Contact:
Thomas Scott, Entomology, (530) 754-4196,
twscott@ucdavis.edu