Panleukopenia is a viral disease mainly affecting young cats. Without appropriate treatment, it is often fatal.
Panleukopenia is a contagious, often fatal, viral disease affecting cats. Its other names include cat plague, feline infectious enteritis, infectious agranulocytosis, feline parvoviral disease and feline distemper. In young, unprotected cats, its course is generally peracute to acute and the mortality rate can be up to 75 %. In cats over 4 months old, it tends to be mild or even entirely without clinical symptoms.
The only protection available is regular vaccination as recommended by the German Standing Committee on Veterinary Vaccination (StlKoVet).
In the event of infection, it is vital to act quickly. Besides replacing lost fluids, the animal should immediately be given neutralising antibodies.
The disease is caused by a parvovirus which can survive in the environment for extended periods and replicates notably in rapidly dividing cells.
he agent is feline panleukopenia virus (FPV), a member of the Parvovirus genus. FPV is a non-enveloped DNA virus. The disease is closely related to mink enteritis and canine parvovirus infection, which is why the virus genome bears many similarities to that of canine parvovirus.
Cats are susceptible not only to feline parvovirus, but also to infection with canine parvovirus.
The virus is highly stable in the environment and can remain infectious for approximately a year at ambient temperature. It is also extremely resistant to commonly used disinfectants.
The virus is excreted primarily in the faeces of infected animals. It can be transmitted by direct contact or by vectors. The latter include contaminated objects and live vectors such as other pets, prey animals, and people. Another transmission route is intrauterine infection of unborn kittens, which can lead to serious foetal damage.
Cats with an undetected infection, and animals which have recovered, may become chronic excreters or 'shedders' and increase the pressure of infection in the environment for unprotected cats.
Infection is by the faecal-oral route, via direct contact, or indirectly via contaminated animate or inanimate vectors. The latter include contaminated objects, other pets, prey animals, and people. Transplacental infection is also possible.
The virus enters the animal's body via the mucous membranes of the nose and throat. This is also where initial virus replication takes place. After 18 to 24 hours, the virus spreads throughout the body. It has a particular affinity for the rapidly dividing cells of the lymphatic tissue, bone marrow and mucous membranes of the small intestine.
The first clinical symptoms appear 3-12 days after infection. They include:
Due to the destruction of white blood cells and the immune defences, animals may develop bacterial secondary infections.
Particularly at risk are kittens which lack sufficient maternal antibodies, either as a result of the immunological gap or because the mother cat was not or was not effectively vaccinated.
The disease frequently proves fatal in these animals, due to the often serious bloody diarrhoea and accompanying massive fluid loss. The course of the disease is generally peracute to acute, and sudden death is not uncommon. The mortality rate can be up to 75 %.
In older cats, the disease tends to be mild or without symptoms. However, FPV infection in adult cats may lead to a weakening of the immune system, which encourages other diseases. Subacute infection is characterised by lack of energy and mild diarrhoea, and may lead to chronic diarrhoea due to destruction of the intestinal mucosa and subsequent bacterial secondary infection.
Some kittens which contracted the virus in the uterus or during birth may develop feline ataxia. This condition is characterised by movement and coordination disorders, recognisable from the kitten's wobbly, stiff-legged, jerky walk.
If these weak-born kittens do not die soon after birth, they are usually left with life-long coordination problems. This particular form of FPV infection is based on a developmental disorder of the cerebellum (cerebellar hypoplasia) and possibly of the retina.
A tentative diagnosis can be established within the first 10 days after infection by conducting laboratory tests on faecal samples.
A tentative diagnosis can be made on the basis of the clinical symptoms. Other characteristic features are the greatly reduced number of white blood cells (leukopenia) and the usually higher proportion of red blood cells due to fluid loss.The virus can be detected during the first 10-14 days after infection by testing faecal samples. This is possible because large quantities of virus are excreted in the faeces. False-negative results may be obtained if the test is carried out immediately after the first clinical symptoms appear. In this case, the test should be repeated after a few days if a diagnosis is still required.
Treatment consists of fluid replacement, the giving of neutralising antibodies, and antibiotic therapy.
Infected animals often suffer from severe fluid loss and electrolyte imbalance. Treatment therefore consists of fluid and electrolyte replacement in combination with antibiotics and the administration of a hyperimmune serum containing neutralising antibodies to panleukopenia virus. Depending on the severity of the case, fluid substitution should be provided by intravenous or subcutaneous infusion.
The hyperimmune serum containing neutralising antibodies to panleukopenia virus produces a passive and therefore temporary immunity to the virus.
The hyperimmune serum is obtained from donor animals that have been immunised multiple times. Multiple immunisation causes the donor animals to produce higher levels of antibodies. After collection by blood sampling and further processing, they become purified, highly effective antibodies available for use in prevention and treatment.
In contrast to non-specific stimulation of the immune system using paramunity inducers, these antibodies are immediately effective.
The use of a hyperimmune serum buys valuable time in the fight against infectious disease!
If antibodies are administered promptly and can take effect before the virus spreads, even small quantities are highly effective. The use of antibody serum is therefore indicated even on suspicion of panleukopenia or during the incubation period.
After using antibody serum as an acute treatment measure, appropriate active immunisation should be carried out to maintain the resulting protection.
The preventive use of hyperimmune serum during the immunological gap greatly reduces mortality.
The main way of protecting against infection with FPV is by administering live vaccines. The German Standing Committee on Veterinary Vaccination (StIKoVet.) recommends panleukopenia vaccination for all cats. Kittens should be vaccinated at 8, 12 and 16 weeks of age and again at 15 months. Vaccination boosters should then be given at regular intervals (1-3 years) in accordance with the manufacturer's instructions. Breeding females should be fully immunised (e.g. by giving repeat vaccinations before mating), to enable them to produce high levels of maternal antibodies.
However, there is a close connection between the presence of maternal antibodies and the success of vaccination in kittens. Even low levels of maternal antibodies may interfere with the development of reliable vaccine protection. Breeders vaccinating regularly may therefore find that panleukopenia virus infection still occurs. If mother cats are fully immunised, the kittens receive large volumes of maternal antibodies which persist until the first vaccination at 8 weeks of age and beyond.
During this immunological gap, or generally in animals assumed to have increased susceptibility to infection, the preventive use of an antibody serum to provide temporary protection for kittens or weakened animals is advisable.
The immediate passive protection conferred by giving hyperimmune serum allows the immune system to mature and later longer-lasting protection as a result of active immunisation.
Other prophylactic indications might be a temporary stay in an unfamiliar environment with an unknown pathogen reservoir, or immunosuppressive influences (e.g. cat shows or holiday care in unfamiliar surroundings). This applies especially to geriatric and ailing animals.
To protect other animals against infection, animals that have recovered should be kept separate from other susceptible animals for 2 to 4 weeks after recovery. All objects that might carry infection should be cleaned with an effective disinfectant. Faeces should always be removed. It is also important to practise good hygiene, to prevent people from spreading the virus.