Nosocomial feline calicivirus-associated virulent systemic disease in a veterinary emergency and critical care unit in France.

CASE SERIES SUMMARY: In October 2011, an abnormally large morbidity and mortality event was noted in the intensive care unit (ICU) of a veterinary school hospital in Nantes, France. Cats, and cats only, transferred from the emergency room presented with fever, ulcers on the tongue and cutaneous lesions around venepuncture or surgical incision sites, leading to suspicion of a feline calicivirus-associated virulent systemic disease confirmed with reverse transcriptase-polymerase chain reaction. A total of 14 cats were suspected. The clinical features and the origin of the contamination were described for each cat. The median length of incubation was 4.5 days. Fifty-seven percent of the cats were euthanased (8/14) and 21% died (3/14), with a combined mortality of 79% (11/14) - the highest ever reported. Median survival was 12 days. The recovery rate was 21% (3/14).

RELEVANCE AND NOVEL INFORMATION: Eight outbreaks have been reported, in veterinary clinics or in group-housed cats. The main unusual aspects of the present outbreak were: (1) the extreme flare-up of lesions at sites of skin breach, precluding any puncture/incision; (2) the suggested better survival rate at home than in hospital; and (3) the immediate control of the outbreak after recognition of the disease. Other striking but less unusual features of this outbreak were: (4) the increasing of the virulence of the calicivirus with the passage of time; and (5) the primary role that the caregivers' hands played in the spread of the outbreak.