An epizootic of feline herpesvirus, type 1 in a large specific pathogen-free cat colony and attempts to eradicate the infection by identification and culling of carriers.
This study describes the clinical course of an inadvertent feline herpesvirus, type 1 (FHV-1) outbreak in 2 specific pathogen-free (SPF) research and breeding colonies housing 690 cats and assesses a programme that was designed to eradicate the virus from the colonies. The clinical signs observed in these cats were milder, with more eye involvement than those previously described for FHV-1 infection and did not include abortion. FHV-1 eradication was based on the detection and elimination of both active and latent viral carriers. Carrier cats were detected by virus isolation from oral swabs before and after corticosteroid-induced reactivation of FHV-1 excretion. Four per cent of recovered cats were actively shedding virus prior to corticosteroid treatment; 21% of the virus negative cats shed virus after one corticosteroid injection, and 12% of remaining culture negative cats tested positive upon a second corticosteroid treatment 6 weeks later. The colony remained virus free for 8 months after all detectable virus carriers were culled and there was no seroconversion among new kittens. A second epizootic of FHV-1 then occurred among susceptible animals. At this time, all breeding cats that had tested negative after 2 injections of corticosteroids were treated a third time; 23% of them now tested positive for FHV-1. This study demonstrates that corticosteroid treatment can be useful in improving the rate of detection, essential as a basis for decreasing the incidence of enzootic disease, but it is unlikely to detect all possible FHV-1 carriers in large populations of cats.
Hickman
M A
MA
Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis 95616.
Reubel
G H
GH
Hoffman
D E
DE
Morris
J G
JG
Rogers
Q R
QR
Pedersen
N C
NC
D000818:Animals; D000830:Animals, Laboratory / Q000821:virology*; D002353:Carrier State / Q000662:veterinary / Q000821:virology; D002371:Cat Diseases / Q000453:epidemiology / Q000517:prevention & control / Q000821:virology*; D002415:Cats; D004196:Disease Outbreaks / Q000662:veterinary; D005260:Female; D006564:Herpesviridae / Q000302:isolation & purification; D006566:Herpesviridae Infections / Q000453:epidemiology / Q000517:prevention & control / Q000662:veterinary*; D008297:Male; D013047:Specific Pathogen-Free Organisms