Feline Panleukopenia

What is panleukopenia?

The term panleukopenia refers to a decrease in the number of white blood cells in the body. White blood cells play a major role in immunity and are important in defending against infections and diseases. In severe panleukopenia, white blood cell numbers may drop from the normal of several thousand per milliliter of blood to just a few hundred. This low number of white blood cells makes an affected cat extremely vulnerable to other infections.

What causes feline panleukopenia?

Feline panleukopenia (FPL), also sometimes called feline distemper, is caused by a virus in the parvovirus family known as feline panleukopenia virus (FPLV). A similar but distinct virus causes parvovirus disease in dogs. Parvoviruses are extremely tough viruses and are only killed by strong disinfectants, including 2% household bleach. FPLV can survive in some environments for a year or more. These viruses attack rapidly dividing cells, so other cells in the bone marrow (red blood cells, platelets) and cells of the gastrointestinal tract are also commonly affected.

How is this infection transmitted?

The feline panleukopenia virus is present in all excretions of infected cats, particularly the feces. A susceptible cat can be infected by direct contact with an infected cat, or the virus can be transferred via contaminated water, food bowls, or on shoes and clothing. The incubation period from infection until clinical signs develop is typically three to five days, and seldom longer than a week.

What are the clinical signs of FPL?

Clinical signs of FPL can vary, but typically cats experience depression or listlessness, which may progress to collapse. The virus infects and destroys rapidly growing cells, so the intestinal tract is also often affected. Vomiting and diarrhea are frequent, and diarrhea may contain blood. The hair coat quickly becomes dull and rough, and the skin loses its elasticity due to dehydration.

Often, cats with FPL develop other infections because their immune system is weakened. They may have purulent (green/yellow) discharge from the eyes and nose. In young kittens with severe infections, sometimes the only clinical sign is sudden death.

In a pregnant cat, the infection can result in fetal death. Kittens that survive may have abnormal development of a region of the brain called the cerebellum (cerebellar hypoplasia). This development results in tremors and an abnormal gait with exaggerated movements. Affected cats adapt well to this disability and can lead relatively normal lives.

Can FPL be treated?

As with most viral diseases, there is currently no treatment for FPL. Antibiotics do not kill viruses, but they help control the secondary bacterial infections that commonly develop due to the lack of white blood cells and the resulting reduced immunity. Dehydration and shock are life-threatening components of FPL, and intravenous fluid therapy and intensive nursing care are critical. If the cat receives aggressive supportive care through the initial stages of illness, the prognosis for a full recovery is good.

How can I protect my cat against FPL?

Fortunately, excellent vaccines are available and are part of the core feline vaccination program. Kittens require boosters of this vaccine starting at six to eight weeks of age. These boosters are given every three to four weeks until the kitten is 16–20 weeks of age, and then are followed by at least one booster a year later. Cats and kittens over 16 weeks of age need an initial series of two vaccinations three to four weeks apart.

The immunity produced by the FPL vaccine is generally strong, but it decreases with time and at a faster rate in some cats than others; therefore, booster vaccinations every one to three years are strongly recommended. Your veterinarian will discuss the appropriate frequency of booster vaccinations for your cat’s lifestyle.

Are there any side effects to the vaccination?

Modern FPL vaccines are safe and side effects are uncommon. However, as with all vaccines, some cats may be lethargic for a day or two after administration. Very rarely, a more severe allergic reaction, called anaphylactic shock, may occur due to an individual’s sensitivity to one or more components of the vaccine. Such severe reactions, if they occur, usually happen within a few minutes of vaccination, but may be delayed by hours in some cats. If you observe signs such as difficulty breathing, facial swelling, or any other signs of distress, call your veterinarian immediately.

Be sure to discuss any concerns you may have about vaccinations with your veterinarian.