Panleukopenia (Feline Distemper)
Feline panleukopenia, also known as feline infectious enteritis or feline parvoviral disease, is an acute, severe and highly contagious disease primarily of kittens and unvaccinated older cats. Feline panleukopenia has also been referred to as feline distemper, although the causative organism is not related to the virus that causes distemper in dogs. FPL affects all body tissues containing rapidly dividing cells, especially those in the digestive tract. It is caused by the feline parvovirus and is characterized by the acute onset of vomiting, diarrhea, dehydration, depression, and commonly death.
Causes of Feline Panleukopenia
The virus that causes feline panleukopenia is quite similar to the canine parvovirus that is responsible for severe gastrointestinal disease in dogs. The feline parvovirus can infect all cats, both domestic and wild, as well as raccoons, ferrets and mink, which often act as reservoirs for the viral organisms. The virus is shed in the bodily excretions of affected animals for up to 6 weeks following infection and has a particular affinity for feline feces. Feline parvovirus is very resistant to most disinfectants and can survive in the environment for months to years. Cats become infected by direct exposure to infected feces, salivary secretions or viral particles on inanimate objects (shoes, food and water dishes, towels, clothing, etc.). The virus can also be transmitted in utero from infected queens to their unborn offspring or to newborns during grooming.
Prevention of Feline Panleukopenia
Vaccination is highly effective for preventing feline panleukopenia. Both modified live and inactivated viral vaccines are available, but the modified live (attenuated) vaccines seem to be more effective and produce more rapid immunologic protection. Both types of vaccines can be given either intranasally (by being squirted into the cat's nasal cavities) or by the more familiar intramuscular injection. Pregnant cats and kittens younger than 6 weeks should not be vaccinated with the modified live product due to potentially adverse developmental consequences. Current vaccine protocols call for vaccinating kittens at or after 8 weeks of age, then at 12 and 16 weeks, with a booster one year later. Although that booster may provide lifelong protection, most authorities recommend revaccinating every 3 years.
The feline parvovirus is extremely hardy and can live in soil, cracks between tiles, carpets and furniture for months to years. The most effective way to eliminate it in the environment is through thorough disinfection with a dilute solution of 1:32 bleach to water.
The feline parvovirus targets white blood cells, which is the source of its name (white blood cells are also known as leukocytes; panleukopenia refers to an abnormally low number of circulating white blood cells). Feline panleukopenia is largely preventable by appropriate routine vaccinations. Fortunately, the feline parvovirus does not infect dogs or people.
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)
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)
Abdominal pain (often severe and debilitating; cat may be hunched up and in obvious discomfort)
"Fading kitten" syndrome
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.
Feline panleukopenia, also known as feline infectious enteritis or feline parvoviral disease, is not especially easy to diagnose. However, in most cases, information from physical examination, history, clinical signs and routine in-clinic blood tests can be used to arrive at a presumptive diagnosis.
How Feline Panleukopenia is Diagnosed
The feline parvovirus has a particular affinity for attacking a cat's white blood cells (leukocytes), which are essential components of the immune system. As a result, blood samples from infected cats frequently show a greatly reduced number of circulating white blood cells – especially in young or unvaccinated cats. This condition, called "leukopenia," gives this illness its name. Affected cats also commonly are anemic, which means that they have a low circulating red blood cell count as well. Kittens with severe gastrointestinal symptoms, together with a low white and red blood cell count, are probably infected with the feline parvovirus.
Diagnostic laboratory tests for feline parvoviral infection do exist. They include immunofluorescent antibody testing (IFA), polymerase chain reaction tests (PCR), serologic examination (specific blood tests) and virus isolation. However, these tests are time- and labor-intensive and are not commonly used or readily available.
The in-clinic fecal test used to diagnose parvoviral infection in dogs can also be used to detect the presence of feline parvovirus in an infected cat's fecal sample.
Once clinical signs of feline parvoviral infection develop in cats, the chance of a complete recovery is not good. Immediate and intense supportive care, preferably started very early in the course of the disease, may enhance the animal's quality of life and increase its relatively slim chances of recovery.
Feline panleukopenia is a serious, highly contagious parvoviral infection of cats. There is no cure for FPL - that is, there is no way to effectively eliminate the virus from circulation once a cat is infected. However, supportive and management protocols are available to increase affected cats' chances of survival and improve the quality of their lives.
The primary effects of feline panleukopenia - vomiting, diarrhea, dehydration, depression and dangerous secondary bacterial infections - will quickly become life-threatening if not treated swiftly and aggressively. Treatment for cats with parvoviral infections is similar to that for dogs with parvoviral infections and must be done on an inpatient basis early in the course of the disease. Because this virus is extremely contagious, affected cats should be strictly isolated from other cats if at all possible. Caretakers of infected cats should take extra precautions to remove and replace shoes and clothing and thoroughly clean their hands and arms before coming into contact with non-infected animals.
Intensive supportive care, including intravenous fluid therapy, is necessary to re-hydrate infected cats and manage shock and electrolyte abnormalities. There are no specific antiviral drugs currently available to treat feline panleukopenia. Therapy centers on managing the symptoms of the disease to make the cat as comfortable as possible. The virus is particularly lethal in unvaccinated young kittens. Older cats with stronger immune systems have a better prognosis, but even their chances of survival are not promising.
Broad-spectrum antibiotics are often given intravenously to combat secondary bacterial infections, but only after the cat's hydration status is normalized so that it is able to handle the effects of medication. Expectorants or other cough suppressants can be used to help manage the bronchitis and pneumonia that frequently accompany this illness. Anti-emetics, such as metoclopramide and others, can be given intravenously or orally to help soothe the adverse effects of nausea and vomiting. If the cat has become dangerously anemic (a significant reduction in the number of circulating red blood cells), whole blood transfusions may be available, but usually only at specialized clinics, referral centers or veterinary teaching hospitals. If the cat is unable or unwilling to eat for an extended period of time, additional nutritional support and appetite stimulants can be used. Anti-seizure medications may be administered if necessary, and of course appropriate pain management is essential to the cat's comfort.
Successful treatment of feline panleukopenia generally takes at least one week, but it can take weeks or even months for the cat to regain its health.
Unfortunately, kittens that develop feline panleukopenia have a guarded prognosis. Older cats have a better chance of surviving the disease. If a cat survives feline parvoviral infection, it normally will have no permanent adverse side effects and will acquire life-long immunity to the disease. However, it will continue to shed the virus in bodily secretions for several weeks.