Transmission
The feline panleukopenia virus is considered ubiquitous, meaning it is in virtually every place that is not regularly disinfected. The infection is highly contagious among unvaccinated cats.Antibodies against FPLV, produced by the adaptive immune system, play an important role in the feline response to the virus. Maternally-derived antibodies (MDA) efficiently protect kittens from fatal infection. This passively acquired immunity is later replaced by an active immune response obtained by vaccination or as a consequence of a natural infection. In kittens, the period of greatest susceptibility to infection is when maternal antibodies are absent, or waning, and vaccine-induced immunity has not yet fully developed.Free-roaming cats are thought to be exposed to the virus during their first year of life. Those that develop a subclinical infection or survive acute illness mount a robust, long-lasting, protective immune response.An infected cat sheds large amounts of virus in all body secretions including feces, vomit, urine, saliva, and mucus during the acute phase of illness. It can continue to shed the virus for as long as 6 weeks after recovery. Subclinically ill cats can also shed the virus in body secretions. The virus can be carried or transferred on an infected object (such as bedding, food dishes, fur) or by other animals, fleas, and humans  (see: fomites). It persists long after evidence of the original body secretion has faded away, and can be transported long distances. Like all parvoviruses, FPLV is extremely resistant to inactivation and can survive for longer than one year in a suitable environment.
These tests are used extra-label because they allow rapid, inexpensive, in-house detection of the virus.) Some cats will have completed the shedding period by the time the test is run, leading to false-negative results. Electron microscopy, virus isolation and seroconversion can also be used to document active or recent infection. Leukopenia on a complete blood count (nadir 50–3,000 WBC/μL) supports a diagnosis of FPLV. In an unvaccinated cat, the presence of antibodies against FPV indicates that the cat either has the disease or has had the disease in the past. Elevated IgM titers (1:10 or greater) indicate active infection and if clinical signs are obvious (diarrhea, panleukopenia) the prognosis is poor. Elevated IgG titers (1:100 or greater) in a cat with clinical signs indicates a better prognosis.Differential diagnoses include salmonellosis, enteric toxins, feline immunodeficiency virus (FIV), feline leukemia virus (FeLV), cryptosporidiosis, pancreatitis, septicaemia with acute endotoxemia, toxoplasmosis, peritonitis, and lymphoma. Treatment
To contain the virus, cats with suspected or diagnosed FPLV should be kept in isolation.It requires immediate, aggressive treatment if the cat is to survive, as it can be fatal in less than 24 hours. Several articles and publications provide guidance for rescuers and veterinarians for optimizing outcomes.Treatment involves:
anti-emetics
IV antibiotics
intravenous fluids with electrolytes
injections of vitamin B
plasma or whole blood transfusionFeeding should be continued as long as possible. A highly digestible diet is preferred, but the individual animals preferences may dictate giving whatever it will eat.