Download Scientists collaborate on study of West Nile Virus

Scientists collaborate on study of West Nile Virus
By Kim Colavito Markesich
Antonio Garmendia, associate professor of pathobiology, recently completed the research
portion of a collaborative project in Madrid, Spain, with Juan Carlos Saiz, a scientist at
the INIA Ministry of Science and Technology in Madrid. Garmendia and Saiz met as
postdoctoral fellows students at Plum Island Animal Disease Center.
Saiz called Garmendia as West Nile fever reached Portugal, France, and Italy, concerned
that Spain was next. Garmendia agreed to participate as an external consultant in a West
Nile surveillance project in of Spain. That led to the research collaboration with Saiz
during the fall of 2004.
Garmendia was involved with the initial isolation of the virus in the United States. Since
its introduction in the Northeast, the disease can now be found throughout the U.S.,
several Canadian provinces, and northern Mexico.
“When the virus first hit, thousands of birds died. It was particularly striking in the
United States,” Garmendia remarks. Once an infectious disease becomes established,
natural selection takes over as some resistant animals survive. These carriers become
persistently infected, spreading the disease rather than immediately succumbing to it.
Says Garmendia, “During the normal virus cycle, the virus is transmitted by mosquitoes,
primarily to birds. We found a hawk during the winter of 2000 that succumbed to West
Nile of an acute death. The hawk probably ingested infected animal. This means that the
virus can overwinter. So we ask, where is the virus during the winter when there are no
mosquitoes?”
The virus could be wintering in small prey such as snakes or frogs, or in small mammals
such as rodents. In mammals, the mother may transfer the virus during pregnancy, with
the offspring serving as a reservoir for the virus.
The Spain project examined the distribution of the virus, as well as the persistence in
different organs and tissues. “Most of the West Nile virus research has been focused on
birds, horses, and humans,” says Garmendia. “Very little is known about the disease in
other species such as wild mammals.”
“The next step is to find out how the virus is being maintained,” says Garmendia. “If we
understood that, we could control it better.”
The project consisted of two mouse models: adult mice to model the general population
in nature, and pregnant mice to model maternal-fetal transmission.”
“We wonder whether infection during pregnancy can be one of the mechanisms of viral
persistence in nature,” he says. Currently, hundreds thousands of samples are being
studied and processed. In addition to Garmendia and Saiz, several other members of the
team are assisting with sample analysis. These include Mariano Domingo, PhD, a
veterinary pathologist and director of CReSa at Bellaterra, a state laboratory in
Barcelona; Estela Escribano, postdoctoral fellow, and Laura Cordobvae, graduate
student, both from the University of Madrid.
Garmendia enjoyed working in Spain and plans to invite Saiz here as they complete the
project. “It was a very productive collaboration,” Garmendia remarks. “I’m looking
forward to reviewing the data over the next few months.”