Feline Panleucopenia

Also known as:

Feline Infectious Enteritis Feline Parvovirus

Description

Feline panleucopenia is a viral infection of cats caused by feline parvovirus (FPV). Feline parvovirus is a small, non-enveloped, single-stranded DNA virus of one serotype only, that is closely related to canine parvovirus type 2 (CPV-2). In order to replicate, FPV must infect dividing cells, and so tissues with a high mitotic rate undergo actue cytolysis. FPV is very stable in the environment and may survive for years on infected premises. It is also highly contagious.

Feline panleucopenia takes its name from the severe depletion of leucocytes thats results from FPV infection. As well as targeting immune cells, FPV destroys the cells of the intestinal crypts causing enteritis, villous atrophy and malabsorption. In utero infection of foetuses can occur, leading to foetal death, resorption, mummification, abortion or stillbirth. In neonatal kitten the retinal cells of the eye and the granular cells of the epithelium are rapidly dividing. Infection of these by FPV causes permanent retinal dysplasia and cerebellar hypoplasia.

Signalment

Although routine vaccination can give almost complete control of feline panleucopenia, the disease is seen worldwide in unvaccinated populations. All domestic and exotic felids may contract FPV, as well as some exotic canids. Mink are particularly susceptible, and infection may also be seen in racoons, pandas and coatimundi. Although there are no breed or sex predilections, the severity of disease varies with age. Once maternal immunity has waned, unvaccinated, previously unexposed cats can become infected at any age. However, severe infections are most likely in kittens of 2-6 months of age, and adults usually suffer on mild or subclinical disease.

Diagnosis

Clinical Signs

Certain elements of a patient's history may be suggestive of feline panleucopenia. For example, the animal may have recently been exposed to a potential source of infection, such as a cattery, or be a kitten obtained from a premisis with a history of feline panleucopenia. Lack of vaccination, or vaccination before the demise of maternally-derived antibodies, may also point to FPV infection. Owners usually report a sudden onset of illness including vomiting, diarrhoea, depression and complete anorexia, and cats are often said to hang their head over the food or water bowl but not actually eat or drink.

Gross Pathology

The virus targets crypt cells and lymphoid areas,causing villus atrophy. In the cat, the intestine becomes thickened, turgid and swollen, with a pale, dull and mottled appearance.

The contents appear rather dry, and this becomes increasingly evident lower down the gut.

Lower down in the gut, enteritis is apparent. In the cat this is fibrinous enteritis, and in the dog it is haemorrhagic.

Histological Pathology

The crypt lining cells undergo complete necrosis, but very little inflammation is seen. Fibrinous exudates may be seen on surface of the mucosa. However,the submucosa and lamina propria are often unaffected. Cyst-like structures are seen in the deepest parts of the glands of the intestinal mucosa after only a few days of infection. These cystic glands are lined with flattened epithelial cells.

Inclusion bodies may also be seen, but these are often very hard to find.

The Lymph nodes appear pale and oedematous, and almost aplastic. The Bone marrow appears pale and fatty looking and is depleted of cells.

Treatment

Modified live and inactivated virus vaccines are avaliable, with boosters every 1-2 years required. One should also try to prevent exposure to kittens with feline panleukopenia.