Viral Diseases In Cats : Part 2

VIRULENT SYSTEMIC FELINE CALICIVIRUS

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.

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. 

FELINE PANLEUKOPENIA  

Feline panleukopenia, also called feline infectious enteritis, is a leading cause of death in kittens. It has been called feline distemper, but it bears no relation to the virus that causes distemper in dogs. There may, however, be crossover infectivity between cats and the newer forms of parvovirus isolated in dogs.

Panleukopenia virus is present wherever there are susceptible animals. Mink, ferrets, raccoons, and wild cats all serve as a reservoir. The virus is highly contagious. It is spread by direct contact with infected animals or their secretions. Contaminated food dishes, bedding, litter boxes, and the clothes or hands of people who have treated an infected cat are other routes of exposure.

The panleukopenia virus has a special affinity for attacking white blood cells. The reduction of circulating white cells (leukopenia) gives the disease its name. Signs of acute illness appear two to ten days after exposure. Early signs include loss of appetite, severe apathy, and fever up to 105°F (40.5°C). The cat often vomits repeatedly and brings up frothy, yellow-stained bile. The cat may be seen crouching in pain, his head hanging a few inches over the surface of the water bowl. If he is able to drink, he immediately vomits. With pain in the abdomen, the cat cries plaintively.

Diarrhea may appear early in the course of the disease, but frequently comes on later. The stools are yellow or blood-streaked. In young kittens (and some older cats), the onset can be so sudden that death occurs before the owner realizes the cat is ill. It may seem as if the cat was poisoned.

Panleukopenia can be transmitted to kittens both before and shortly after birth. In such cases, the mortality rate is 90 percent. Kittens recovering from neonatal infection may have cerebellar brain damage and exhibit a wobbly, jerky, uncoordinated gait that is noted when they first begin to walk. Secondary bacterial infections are common. The bacterial infection, rather than the virus itself, may be the cause of death. 

A white blood cell count confirms the diagnosis. In-office tests for canine parvovirus will also detect feline panleukopenia virus, which is a member of the parvovirus family.

Cats who survive are solidly immune to reinfection but can shed the virus for several weeks. Along with asymptomatic carriers, this leads to repeated exposure in a population of cats. The repeated exposure helps to boost immunity among cats who have already acquired protective antibodies, by continuing to stimulate their immune systems.

Treatment: 

Detecting panleukopenia early in the course of the illness is of prime importance, because intensive treatment must be started at once to save the cat’s life. It is better to consult your veterinarian on a false alarm than to wait until the cat is desperately ill. Supportive measures include fluid replacement, antibiotics, maintaining nutrition, and, occasionally, blood transfusions.