Research Communications of the 24th ECVIM-CA Congress

All affected cats tested FCV-positive but negative for FHV-1, FeLV and FIV, except for one kitten from outbreak 4 (FIV-positive). All cats in outbreaks 1 and 3 recovered, whereas all cats in outbreaks 2 and 4 died or were euthanized because of clinical deterioration. Each outbreak was caused by a phylogenetically distinct VS-FCV strain. In shelter 1, the queen and three in contact cats remained asymptomatic although infected with the same VS-FCV strain. Furthermore, 7/27 other cats of shelter 1 were infected with closely related, but distinct FCV strains. The VS-FCV isolates from the two outbreaks in shelter 2 were distinct but phylogenetically related. All VS-FCV isolates from cats from the same outbreak showed a similar virus neutralization pattern, but neutralization differed between different outbreaks.