Pathogenesis of experimentally induced rabies in domestic ferrets

Michael Niezgoda From the Viral and Rickettsial Zoonoses Branch, Division of Viral and Rickettsial Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, 1600 Clifton Rd, Atlanta, GA 30333 (Niezgoda, Shaddock, Rupprecht); the Department of Veterinary Diagnostic Investigation, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506 (Briggs); and the Department of Medical Microbiology, College of Veterinary Medicine, University of Georgia, Athens, GA 30602 (Niezgoda, Dreesen).

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Deborah J. Briggs From the Viral and Rickettsial Zoonoses Branch, Division of Viral and Rickettsial Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, 1600 Clifton Rd, Atlanta, GA 30333 (Niezgoda, Shaddock, Rupprecht); the Department of Veterinary Diagnostic Investigation, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506 (Briggs); and the Department of Medical Microbiology, College of Veterinary Medicine, University of Georgia, Athens, GA 30602 (Niezgoda, Dreesen).

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John Shaddock From the Viral and Rickettsial Zoonoses Branch, Division of Viral and Rickettsial Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, 1600 Clifton Rd, Atlanta, GA 30333 (Niezgoda, Shaddock, Rupprecht); the Department of Veterinary Diagnostic Investigation, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506 (Briggs); and the Department of Medical Microbiology, College of Veterinary Medicine, University of Georgia, Athens, GA 30602 (Niezgoda, Dreesen).

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David W. Dreesen From the Viral and Rickettsial Zoonoses Branch, Division of Viral and Rickettsial Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, 1600 Clifton Rd, Atlanta, GA 30333 (Niezgoda, Shaddock, Rupprecht); the Department of Veterinary Diagnostic Investigation, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506 (Briggs); and the Department of Medical Microbiology, College of Veterinary Medicine, University of Georgia, Athens, GA 30602 (Niezgoda, Dreesen).

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Charles E. Rupprecht From the Viral and Rickettsial Zoonoses Branch, Division of Viral and Rickettsial Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, 1600 Clifton Rd, Atlanta, GA 30333 (Niezgoda, Shaddock, Rupprecht); the Department of Veterinary Diagnostic Investigation, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506 (Briggs); and the Department of Medical Microbiology, College of Veterinary Medicine, University of Georgia, Athens, GA 30602 (Niezgoda, Dreesen).

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SUMMARY

Objective

To determine susceptibility, incubation and morbidity periods, clinical signs, serologic response, and excretion of virus in domestic ferrets inoculated with rabies virus.

Animals

55 domestic ferrets.

Procedure

5 groups of 10 ferrets were inoculated with rabies virus, IM, at doses of 105.5 to 101.5 median mouse intracerebral lethal dose. Ferrets were observed and behavior was recorded. Rectal temperature, body weight, and samples from the oral cavity and samples of saliva and blood were obtained. Virus isolation was attempted, using intracranial mouse inoculation and cell culture. Virus neutralizing antibodies were determined by rapid fluorescent focus inhibition test. Ferrets were euthanatized immediately if clinical signs were severe. Rabies was confirmed by direct immunofluorescent antibody test.

Results

Mean incubation period was 33 days (range, 16 to 96 days). Clinical signs included ascending paralysis, ataxia, cachexia, bladder atony, fever, hyperactivity, tremors, and paresthesia. Mean morbidity period was 4 to 5 days (range, 2 to 10 days). Virus antigen was detected in brain tissue from all clinically rabid ferrets. Ferrets given the highest viral dose were euthanatized and had VNA; ferrets receiving the next dilution also were euthanatized, but only 4 had seroconverted. Of 17 ferrets that survived, 5 seroconverted. Survivors remained clinically normal except for 1 that recovered with severe paralytic sequelae. Rabies virus was isolated from the salivary gland of 1 ferret that was euthanatized.

Conclusions and Clinical Relevance

Rabies should be considered as a differential diagnosis in any ferret that has acute onset of paralysis or behavioral changes and a condition that rapidly deteriorates despite intense medical intervention. (Am J Vet Res 1997;58:1327–1331)

SUMMARY

Objective

To determine susceptibility, incubation and morbidity periods, clinical signs, serologic response, and excretion of virus in domestic ferrets inoculated with rabies virus.

Animals

55 domestic ferrets.

Procedure

5 groups of 10 ferrets were inoculated with rabies virus, IM, at doses of 105.5 to 101.5 median mouse intracerebral lethal dose. Ferrets were observed and behavior was recorded. Rectal temperature, body weight, and samples from the oral cavity and samples of saliva and blood were obtained. Virus isolation was attempted, using intracranial mouse inoculation and cell culture. Virus neutralizing antibodies were determined by rapid fluorescent focus inhibition test. Ferrets were euthanatized immediately if clinical signs were severe. Rabies was confirmed by direct immunofluorescent antibody test.

Results

Mean incubation period was 33 days (range, 16 to 96 days). Clinical signs included ascending paralysis, ataxia, cachexia, bladder atony, fever, hyperactivity, tremors, and paresthesia. Mean morbidity period was 4 to 5 days (range, 2 to 10 days). Virus antigen was detected in brain tissue from all clinically rabid ferrets. Ferrets given the highest viral dose were euthanatized and had VNA; ferrets receiving the next dilution also were euthanatized, but only 4 had seroconverted. Of 17 ferrets that survived, 5 seroconverted. Survivors remained clinically normal except for 1 that recovered with severe paralytic sequelae. Rabies virus was isolated from the salivary gland of 1 ferret that was euthanatized.

Conclusions and Clinical Relevance

Rabies should be considered as a differential diagnosis in any ferret that has acute onset of paralysis or behavioral changes and a condition that rapidly deteriorates despite intense medical intervention. (Am J Vet Res 1997;58:1327–1331)

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