Mokola Virus Infection in Domestic Cats in Zimbabwe

Summary

From April 1981 to May 1982, during a rabies epizootic, the brains of 6 domestic cats from the Bulawayo area of Zimbabwe submitted for routine rabies examination were found to be infected with Mokola virus. The nervous symptoms displayed by the cats were not considered to be typical of furious rabies although aggression was sometimes evident.

The initial diagnosis of atypical rabies virus infection was made on the basis of poor fluorescence in the fluorescent antibody test using standard rabies conjugate. Latter cases were diagnosed by comparative fluorescence also using a conjugate prepared from one of the isolates. Histopathological examination of the brains revealed extensive viral-type meningo-encephalitis but Negri bodies were not demonstrated. No virus was recovered from the one salivary gland submitted from an infected cat.

The virus was identified as Mokola virus by neutralization index tests in mice, comparing the cat isolates with the other rabies serogroup viruses.

Attempts to infect cats in the laboratory with up to 16,000 mouse lethal doses administered intramuscularly in the neck or subcutaneously in the lip failed, although one jackal and one mongoose were infected experimentally.

The source of the virus and the extent of its spread in Zimbabwe have not been determined.