At one time, parvoviral infection in companion cats was very common. With the development of effective vaccines, this disease is now fairly uncommon in the United States. Unfortunately, it still crops up in kittens and unvaccinated adult cats, especially those kept in crowded, unsanitary living conditions.
Symptoms of Feline Panleukopenia
Affected cats may show no clinical signs of infection. When present, signs of infection tend to be similar to those seen in dogs with “parvo” and develop roughly 2 to 10 days following exposure to the virus. Cats showing the effects of the disease may develop one or more of the following symptoms:
- Loss of appetite (inappetence; anorexia)
- Fever (high)
- Vomiting (production of frothy, yellowish bile-tinged vomitus)
- Diarrhea (may appear early or late in the course of the disease; may be yellow and/or streaked with fresh blood)
- Dehydration (marked)
- Abdominal pain (often severe and debilitating; cat may be hunched up and in obvious discomfort)
- Plaintive vocalization/crying
- Fetal death
- “Fading kitten” syndrome
- Mental dullness
- Cerebellar hypoplasia (lack of coordination/ataxia, wobbly gait; tremors; usually nonprogressive and noticed between 10 and 14 days post-exposure to the virus)
- Sudden death (can happen before clinical signs appear; can resemble death by poisoning)
In addition to attacking the gastrointestinal tract, feline parvovirus also can attack the blood system, nervous system, ophthalmic (eye) tissues, reproductive system and lymphatic system. It can attack the fetus during pregnancy and shortly after birth, causing up to 90% mortality or permanent brain damage in newborns. Secondary opportunistic infections, often bacterial, are also common and can be the actual cause of death in infected cats.
While most cases of feline panleukopenia are subclinical (meaning that infected cats show no outward signs of disease), when clinical symptoms do appear, mortality rates are quite high.
Cats at Increased Risk
Feline panleukopenia tends to target young cats – especially unvaccinated cats between 6 and 12 weeks of age and vaccinated kittens between 8 and 20 weeks of age, when maternal antibodies wane. Females that are vaccinated with modified live viral vaccines during pregnancy are predisposed to delivering kittens with a neurological condition known as cerebellar hypopoplasia. They can also produce mummified fetuses. Most clinical cases of feline panleukopenia are seen in high-density environments, such as animal shelters. While a vaccination is available for this disease, kittens and unvaccinated adults that live in crowded, unsanitary conditions are especially at risk of becoming infected. FPL is frequently fatal.