|Vianna M, C|
Submitted to: Veterinary Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/1/2007
Publication Date: 11/1/2007
Citation: Dubey, J.P., Vianna M, C.R., Kwok, O.C., Hill, D.E., Miska, K.B., Tuo, W., Velmurugan, G.V., Conors, M., Jenkins, M.C. 2007. Neosporosis in Beagle dogs clinical signs, diagnosis, treatment, isolation and genetic characterization of Neospora caninum. Veterinary Parasitology. 149:158-166. Interpretive Summary: Neospora caninum is a single-celled parasite. It causes abortion in cattle and paralysis in companion animals. It is the most important cause of abortion in dairy cattle. Dogs and coyotes are its definitive hosts and main reservoirs of infection. This parasite is transmitted efficiently from the cow to the calf transplacentally. Scientists at the Beltsville Agricultural Research Center report clinical neosporosis in Beagle dogs verified by isolation of the parasite.
Technical Abstract: Clinical neosporosis was diagnosed in a litter of five pups born to a Beagle bitch from Virginia, USA. Four of the pups developed limb weakness starting at 4 weeks of age. The dogs were suspected to have neosporosis based on clinical signs and empirically treated with Clindamycin (75 mg, oral, twice daily-total 150 mg) starting at 9 weeks of age and the dosage was doubled at 13 weeks of age. Antibodies to N. caninum were detected in sera of the dam and pups when first tested serologically at the age of four months. The owner donated the pup with the worst clinical signs and the dam for research; both dogs were euthanized. Viable N caninum was isolated in gamma interferon gene knock out (KO) mice and in cell culture from the pup killed at 137 days of age. Tissue cysts, but no tachyzoites, were found in histological sections of brain and muscles. The isolate was also identified as N. caninum by PCR and sequence analysis and designated NC-9. N. caninum was neither isolated by bioassay in KO mice nor found in histological sections of tissues of the bitch. Clinical signs in the remaining three pups improved considerably after a six month treatment with Clindamycin; N. caninum antibody titers were still persistent in these pups at 23 months of age. Results indicate that medication with Clindamycin can improve clinical condition but not eliminate N. caninum infection.