BLACKSBURG, VA--A veterinary parasitologist in the Virginia-Maryland Regional College of Veterinary Medicine is part of a USDA funded team that has made a major breakthrough in the understanding of a major parasitic disease of cattle.
Working in the college's Center for Molecular Medicine and Infectious Disease, David Lindsay and colleagues have demonstrated that the dog is a "definitive host" for Neospora caninum, a single-celled parasitic organism which causes pregnant cows to abort their fetuses.
While the dog was suspected to be a definitive host (defined as an organism which can support all of the life cycles of a parasite) for Neospora caninum, it had remained unproved since it was discovered in 1988. The organism was identified by USDA microbiologist Jitender Dubey and subsequently isolated in cell culture by Lindsay, who was also working at the USDA.
In California alone, the nation's leading dairy producer, Neospora is believed to be the major cause of cattle abortions estimated to cause $35 million a year in economic loss. The parasite also causes central nervous system disorders in horses and dogs.
As a result of the discovery, the scientific team has recommended producers use fences and adopt cattle management strategies designed to keep pet and stray dogs from defecating in dairy feedlots or pastures. The work was published in the August 14, 1998 issue of the International Journal of Parasitology.
The parasite is passed through cattle populations as dogs or wildlife ingest placental tissues or aborted fetuses discovered in fields and shed oocysts contaminated feces. These feces are in turn eaten by other ruminants, which are subsequently victimized as the parasite continues its life cycle.
Lindsay and the other researchers have drawn their conclusions based
upon experimental work in which the parasite was successfully passed from a
group of Neospora infected mice, through a d
Contact: David S. Lindsay