Feline panleukopenia (also called feline infectious enteritis or feline distemper) is a highly contagious, sometimes fatal, viral disease of cats. Kittens are affected most severely. Feline panleukopenia virus, the parvovirus that causes this disease, occurs worldwide and can persist for more than a year in the environment unless potent disinfectants are used to inactivate it. The term “panleukopenia” refers to an abnormally low level of white blood cells. This disorder is now seen only infrequently by veterinarians, presumably as a consequence of the widespread use of vaccines. However, infection rates remain high in unvaccinated cat populations, and the disease is occasionally seen in vaccinated, pedigreed kittens that have been exposed to high amounts of the virus.

During the initial phase of the illness, virus is abundant in all secretions and excretions of infected cats including saliva, tears, urine, and feces. The virus can be shed in the feces of survivors for up to 6 weeks after recovery. Cats are infected through the mouth and nose by exposure to infected animals, their secretions, or inanimate objects harboring the virus. Most free-roaming cats are exposed to the virus during their first year of life. Those that develop low grade infection or survive short-term illness mount a long-lasting, protective immune response.

In pregnant queens, the virus may spread across the placenta to cause fetal mummification, abortion, or stillbirth. Rarely, infection of kittens in the period just after birth may destroy the lining of the cerebellum, leading to incomplete development of the brain, problems with physical coordination, and tremors.

Most cats infected with the panleukopenia virus show no signs of infection. Those that become ill are usually less than 1 year old. Severe infection may cause death with little or no warning. Short-term infection causes fever, depression, and loss of appetite after an incubation period of 2 to 7 days. Vomiting usually develops 1 to 2 days after the onset of fever. Diarrhea may occur but is not always present. Extreme dehydration develops rapidly in severe cases. Affected cats may sit for hours at their water bowl, although they may not drink much. The duration of illness is seldom more than 5 to 7 days. Kittens under 5 months of age are most likely to die from panleukopenia virus infection.

Your veterinarian will diagnose this disease based on the signs and laboratory tests. Successful treatment of severe cases requires intravenous fluids and supportive care. Electrolyte (salt) imbalances, low blood sugar, low levels of protein in the blood, anemia, and secondary infections often develop in severely affected cats.

Vaccines that provide solid, long-lasting immunity are available. The first vaccination for kittens is usually given at 6 to 9 weeks of age. Your veterinarian will make a recommendation for additional vaccinations based on the health of your cat and your cat's risk of exposure to the virus.

Last full review/revision July 2011 by Otto M. Radostits, CM, DVM, MSc, DACVIM (Deceased); Eugene D. Janzen, DVM, MVS; Jodie Low Choy, BVMS; Dennis W. Macy, MS, DACVIM; Dudley L. McCaw, DVM, DACVIM (Small Animal, Oncology); Barton W. Rohrbach, VMD, MPH, DACVPM; J. Glenn Songer, PhD; Richard A. Squires, BVSc (Hons), PhD, DVR, DACVIM, DECVIM-CA, MRCVS; Bert E. Stromberg, PhD; Joseph Taboada, DVM, DACVIM; Charles O. Thoen, DVM, PhD; John F. Timoney, MVB, PhD, Dsc, MRCVS; Ian Tizard, BVMS, PhD, DACVM; Max J. Appel, DMV, PhD; David A. Ashford, DVM, MPH, DS; Stephen C. Barr, BVSc, MVS, PhD, DACVIM; J. P. Dubey, MVSc, PhD; Paul Ettestad, DVM, MS; Craig E. Greene, DVM, MS; Delores E. Hill, PhD; Johnny D. Hoskins, DVM, PhD