Tracing Tickborne Diseases at Home and Abroad
In tests using a new diagnostic
assay on samples for tickborne
diseases, microbiologist Willard
Goff (right) and veterinary medical
officer Don Knowles examine data
from an automated spectrometer.
|Livestock owners in the United States
and Morocco will benefit from a collaboration between
ARS and the north-African nation.
Twenty-eight million sheep, goats, cattle, donkeys, and horses provide food,
fiber, and transportation in Morocco. Tickborne diseasesbabesiosis,
theileriosis, and anaplasmosiscause illness and death in the animals,
economic loss to their owners, and trade restrictions for the country. But
until now, livestock owners have had no way to differentiate among these three
"Disease-specific tests routinely used in the United States as well as new
tests for anaplasmosis and babesiosis developed at our laboratory can help the
Moroccans determine the prevalence and impact of each disease," says ARS
microbiologist Willard L. Goff.
Immunologist Abdelkebir Rhalem (left)
and graduate student Saadia Lasri
perform a new tickborne-disease test
as Hamid Sahibi, project collaborator
and head of the Department of
Parasitology at Morocco's Institut
Agronomique et Veterinaire, looks on.
| "American livestock owners
benefit, too," says ARS veterinary medical officer Donald P. Knowles.
That's because each new diagnostic test must be performed under a variety of
conditions before it can become an international standard. These standards are
used to protect American animals from foreign diseases. (See "New Test to
Keep Horses Healthy," Agricultural Research, July 2000, p. 8.)
Goff and Knowles work at the ARS Animal Disease Research Unit in Pullman,
Washington. Funded through USDA's Foreign Agricultural Service, researchers
from ARS and USDA's Animal and Plant Health Inspection Service (APHIS) spent 5
years collaborating with
Moroccan scientists to characterize that country's disease problem. Moroccan
colleagues, led by parasitologist Hamid Sahibi and immunologist Abdelkebir
Rhalem, came to Pullman to learn how to use the tests. Then the team set up the
necessary equipment and protocols at the Institut Agronomique et Veterinaire in
Blood samplesand 5,000 tickswere then collected from cattle,
horses, and donkeys at 26 sites throughout the roughly California-sized
country. The tests confirmed the presence of each disease-causing organism,
including the first verification in Morocco of anaplasmosis in cattle.
But theileriosis proved to be the most prevalent tickborne disease in cattle,
with nearly half the samples testing positive. Almost two-thirds of the donkeys
and horses tested were found to have equine babesiosis, also called
The next phase of the research will focus on the ticks that transmit the
diseases. Three tick species were identified as likely carriers, but additional
molecular work is necessary to confirm the role of each species. Jerome Freier,
a geographic information systems specialist with APHIS, will also use remote
sensing with satellite imagery to better define conditions favorable to ticks
and how the ticks are likely to spread.
"With this information, control strategies for these diseases can be
designed in Morocco," says Goff. "All of this research benefits the
disease surveillance program in the United States too."By
Stelljes, Agricultural Research Service Information Staff.
This research is part of Animal Health (#103) and Arthropod Pests of Animals
and Humans (#104), two ARS National Programs described on the World Wide Web at
Willard L. Goff and
Donald P. Knowles are in the
USDA-ARS Animal Disease Research Unit, Washington State University, Pullman, WA
99164-6630; phone (509) 335-6029, fax (509) 335-8328.
"Tracing Tickborne Diseases at Home and
Abroad" was published in the
issue of Agricultural Research magazine.