A new mutation of the calicivirus has been identified in various outbreaks
in cats. The first outbreak was in California, but
outbreaks have since been identified across the United States. The calicivirus
in these cases seems to have mutated to a more virulent form, and is therefore
now known as virulent systemic feline calicivirus (VS-FCV).
The virus may be shed in feces, sloughed skin and hair, and nasal, ocular,
and oral secretions. Asymptomatic and mildly affected cats may transmit the
fatal disease to other cats; therefore, all exposed cats should be considered a
potential infectious risk. This virus is very contagious and easily spread by
both direct contact and on clothes, dishes, bedding, and other objects. Strict
hygiene is required to stop the spread in outbreaks.
Cats are supreme tree-climbing hunters, with strongly muscled backs and hindquarters that give them tremendous power to jump-either horizontally or vertically. It’s normal for cats to jump and climb to high places as they explore their environment. They have sharp, protractile (extendable) claws that serve as useful crampons for climbing.
Along with respiratory signs, cats will show a high fever, edema of the face
and limbs, and ulceration and hair loss on the face, feet,
and pinnas. There may also be other signs seen with more typical feline upper
respiratory diseases, including nasal and ocular discharge, oral ulceration,
anorexia, and depression.
A secondary immune response is believed to be responsible for the organ
damage that accompanies these signs, and leads to a 60 percent fatality rate.
The mortality rate is higher in adults than it is in kittens.
Although this syndrome remains uncommon, occasional outbreaks and clusters
of cases have been documented throughout the United States. So far, this has
occurred in cats of all ages, including those vaccinated for the common
calicivirus as well as nonvaccinates. No other species is known to be affected
by this strain of calicivirus. There is no known risk to human health.
Treatment: For affected cats, treatment consists of supportive care, along
with drug therapy using steroids and interferon. Bovine lactoferrin may be
useful. The efficacy of these treatments is not yet known.
Prevention: Isolate all cats suspected of being infected. VS-FCV can survive
up to four weeks in the environment and is resistant to some disinfectants, but
a bleach solution (diluted with water at 1:32) has been used to effectively
contain previous outbreaks. All surfaces should be thoroughly cleaned and
disinfected. Do not introduce any new cats for at least four weeks.
A new vaccine from Fort Dodge Animal Health, called CaliciVax, has recently
been licensed for control (see page 108).
WebMD Veterinary Reference from "Cat Owner's Home Veterinary Handbook"