Feline Panleukopenia (Feline Distemper)

Overview of Feline Panleukopenia Infection

Feline panleukopenia is a viral disease that usually causes a severe gastroenteritis. It is commonly called feline distemper, and is caused by a specific virus called a parvovirus. Without treatment, it has a very high mortality rate.

Below is an overview on Feline Panleukopenia followed by in-depth information on the diagnosis and treatment of this condition.

The disease is highly contagious and can affect any breed. Young unvaccinated kittens are at a significantly higher risk than other cats. Unvaccinated kittens between 3 and 5 months of age are most commonly affected.

What to Watch For

Aside from the most common gastrointestinal signs, the virus can cause early fetal death and abortions in pregnant queens, neonatal death, and central nervous system symptoms. Some kittens can die rapidly, even within 24 hours of onset of clinical signs. Older cats can develop a subclinical infection, showing minimal signs of illness and experiencing a rapid recovery. Typical symptoms include the following:

• Depression
• Anorexia
• Lethargy
• Fevers
• Vomiting
• Diarrhea
• Weakness

Diagnosis of Feline Panleukopenia

Your veterinarian will start with a complete history, including clinical signs and vaccination status, followed by a physical examination. Other diagnostic tests may include the following:

• Complete blood count (CBC)
• Biochemistry profile
• Feline leukemia virus and feline immunodeficiency virus testing
• Microscopic fecal examination
• Fecal ELISA test for parvovirus
• Fecal cultures
• Abdominal radiographs (x-rays)

Treatment of Feline Panleukopenia

There is no specific treatment for the panleukopenia virus. The therapy is aimed at providing supportive care and for treating the secondary bacterial infection. These include:

• Intravenous fluids
• Injectable broad spectrum antibiotics
• Withholding food and water
• Antiemetic drugs (drugs that control vomiting)
• Intravenous nutritional support
• Blood transfusions
• Recombinant human granulocyte colony stimulating factor (G-CSF)

Home Care

At home a good quality bland diet is fed initially, and your cat’s regular diet is gradually reintroduced. Your veterinarian may also recommend follow-up blood work, such as a CBC and /or biochemistry profile.

Your cat should improve daily; if he survives the acute phase of the disease, the prognosis is good.

Preventative Care

Vaccination offers excellent immunity; the vaccinations are a routine part of a feline pediatric wellness program. Your kitten should receive 2 to 3 vaccinations at 3 to 4 week intervals, starting at 8 weeks of age. The last booster should be given at 12 to 16 weeks old; another booster is given 1 year later. Discuss further vaccinations with your veterinarian.

It is very important for breeding cats to be current on their vaccinations. Pregnant cats should not be vaccinated with modified live virus vaccines, as they can induce disease in the fetus. Also, separate a new kitten from cats with unknown vaccination histories.

Good hygiene practices and appropriate cleaning of the environment are practical methods of limiting virus spread. A 1:32 dilution of sodium hypochlorite (Clorox bleach) is effective in deactivating the virus on surfaces that have been contaminated with infected stool or secretions.

In-depth Information on Feline Panleukopenia

Panleukopenia is a very serious disease, especially in the young cat. The virus may infect any susceptible animal, but kittens between 3 and 5 mouths of age are at higher risk. Adult cats tend to get a sub-clinical disease, and recover rapidly.

The virus is highly contagious and is transmitted through direct contact and secretions (saliva, vomitus, stool, and urine). Cats can also become infected when in contact with a contaminated environment. The virus is resistant in the environment and, under ideal conditions, may remain infectious for one year. Susceptible animals become ill between 2 and 7 days after exposure to the virus.

The panleukopenia virus replicates in rapidly multiplying cells and causes cellular death after replication. The most common areas affected by the virus include the intestinal tract, the bone marrow, and the lymphatic tissue. As the cells lining the inner surface of the intestines become infected, they are destroyed, and vomiting and diarrhea ensue. The loss of fluid from the bowel leads to severe dehydration, and possibly to shock.

When the virus replicates in the bone marrow, the circulating white blood cells, which are produced in the bone marrow, are dramatically decreased in number, resulting in a leukopenia (low white blood cell count); the name “panleukopenia” reflects this decrease in all white blood cell lines. Since white blood cells are vital in fighting infections, their decrease in numbers prevents the cat from initially mounting an effective immune response.

As the virus continues to damage the intestinal lining, the normal bacteria in the bowel penetrate the intestinal barrier, enter the blood stream, and cause a secondary bacterial infection of the blood (sepsis). This combination of events leads to a critically ill patient, and to the clinical signs that are observed.

If a queen is infected while pregnant, the rapidly growing cells of the fetus are affected and fetal or neonatal death may occur. Occasionally, intrauterine infection of the fetus will cause more specific damage to the central nervous system, and especially to the cerebellum (the part of the brain controlling balance and coordination), resulting in a condition known as cerebellar hypoplasia. These kittens may be born alive, but have balance problems as they mature. This can also occur if a pregnant queen is vaccinated with a modified live virus panleukopenia vaccine.

Other Conditions Similar to Feline Distemper

Other conditions may produce clinical signs similar to panleukopenia. These include:

• Feline leukemia virus infection. This virus typically infects young cats, and kittens may also have low white blood cell counts and gastrointestinal signs. However, this tends to be a more chronic disease than panleukopenia.
• Salmonella and campylobacter are bacterial infections that cause severe vomiting and diarrhea. They may be contracted via contact with infected stool or by eating contaminated food.
• Feline coronavirus is another viral infection that infects the gastrointestinal tract. It generally causes much less severe disease than panleukopenia, and is more prevalent in cats over two years of age.
• Severe gastrointestinal parasitic infections may cause young kittens to become quite ill and have signs that include vomiting and diarrhea.
• Other causes of sepsis can also occur in kittens. Bacteria can invade the bloodstream via wounds, infected umbilical cords, perforating gastrointestinal foreign bodies, or from lung infections.
• Intussusception. An intussusception is a condition in which one segment of the intestine telescopes into an adjacent segment of the intestine. This condition usually occurs in young animals and will cause vomiting and diarrhea.
• Intestinal foreign bodies may cause an intestinal obstruction, resulting in a critically ill kitten.
• Dietary indiscretion is a term used to describe eating inappropriate food items. Kittens eating rancid food or getting into garbage may become quite ill, and will present with signs referable to the gastrointestinal tract.

Diagnosis In-depth

An unvaccinated kitten between 3 and 5 months of age that presents with signs of vomiting and diarrhea is suggestive of panleukopenia infection. Many of these kittens are very ill, and have high fevers (104-107 degrees F).

• Complete blood count. The CBC is useful in diagnosing panleukopenia infection, since it evaluates and counts the white blood cells. In the initial stages of the disease a leukopenia develops, with total white blood cell counts usually between 50 and 3000 cells per microliter. Care should be taken when evaluating the white count, however, since after the leukopenia develops, the white blood cell numbers may rebound within 24 to 48 hours. The CBC also evaluates the red cell line; some cats may lose significant amounts of blood through the bowel and become anemic.
• Biochemistry profile. The results of a biochemistry profile can provide critical information. A decrease in blood glucose may be seen in septic animals. The serum electrolytes (sodium, potassium, and chloride) are often abnormal due to gastrointestinal losses. Liver and kidney function may also be abnormal in septic animals.
• Stool analysis. Analysis of a stool sample is always advised to rule out overwhelming gastrointestinal parasitic infections, such as roundworms, hookworms and coccidian.
• Fecal ELISA testing can detect parvovirus in feces or intestinal contents.
• Fecal cultures can be taken for campylobacter and salmonella infections. If these diseases are suspected, the cultures are highly recommended, since they are potentially zoonotic diseases (diseases that can be spread from animals to people).
• Feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV) testing is advised for all seriously ill cats. These viruses cause immunosuppression, and can predispose the cat to other illnesses.
• Abdominal radiographs are recommended to check for evidence of foreign material in the intestine or for potential intussusceptions. The radiographic findings in cats with panleukopenia generally consist of fluid-filled loops of bowel.

Treatment In-depth

There is no specific treatment for the panleukopenia virus. Therapy is aimed at providing supportive care and for treating the secondary bacterial infection. The virus causes a number of potentially life threatening changes, including damage to the intestinal lining, a marked decrease in the number of white blood cells (thereby decreasing the body’s ability to fight infection by decreasing the white blood cells), and severe dehydration or shock due to the marked fluid loss. Treatment is aimed at addressing each of these problems, therefore allowing time for the body to recover and mount an immune response against the virus. If a cat is strong enough when this response is produced, he generally will survive.

Therapeutic Alternatives for Feline Panleukopenia

• Intravenous fluids given to maintain hydration and tissue perfusion. Cats with panleukopenia infection may lose large amounts of fluid through vomiting and diarrhea. Oral supplementation is not adequate; it is critical to replace lost fluids aggressively to prevent or to treat shock. If needed, intravenous fluids may contain supplemental glucose (sugar) and electrolytes, as significant electrolyte losses are common with severe vomiting and diarrhea.
• Intravenous antibiotics are given to prevent or treat septicemia; the antibiotics should be broad spectrum to cover for a wide range of potential bacterial infections.
• Food and water should be withheld from the vomiting cat, since anything that is taken in orally may promote continued vomiting. After there has been no vomiting for about 24 hours, water, and then food, is gradually re-introduced. A good quality, bland, highly digestible diet is used initially.
• Antiemetic drugs are often given to cats with persistent vomiting. These allow for increased comfort and a shorter period of time before food can be started. Common antiemetics used include metoclopramide (Reglan) and chlorpromazine (Thorazine).
• Intravenous nutritional support (parenteral nutrition) can be used to provide nutrition and calories to compromised animals that are unable to eat. This is especially important in septic animals, or in patients undergoing prolonged hospitalization. Intravenous feeding provides the calories and protein needed to give an animal a better chance of overcoming sepsis and severe debilitation.
• If there has been a significant amount of blood lost through the bowel, a blood transfusion may be needed.
• Recombinant human granulocyte colony stimulating factor (G-CSF) is a glycoprotein that stimulates the bone marrow to produce white blood cells. It is occasionally useful if the white blood cell count is not rebounding and remains low. It is not always effective, but it produces rapid results when it does work. G-CSF is not readily available at most veterinary hospitals.

Follow-up Care for Cats with Panleukopenia

Optimal treatment for your pet requires a combination of home care and professional veterinary care. Follow-up can be critical, especially if your pet does not improve rapidly. Cats that recover from the acute illness generally do well, and are protected for life against future panleukopenia infections.

• Administer all medications as directed. Alert your veterinarian if you are experiencing problems treating your pet.
• Some cats may still have some diarrhea when they are sent home. These cats are usually feeling well and are not acting ill. The diarrhea should resolve as the intestinal lining recovers from the viral infection; this may take a week or longer in some cases.
• Recovering cats are initially fed small, frequent meals throughout the day.
• Special diets that are well tolerated by the gastrointestinal tract may also be used initially. These diets are usually given for several days; the cat’s regular diet may be gradually reintroduced as the diarrhea resolves.
• Repeat blood tests may be recommended. A follow-up CBC may be needed to check for improvement of an anemia or leukopenia. A biochemistry profile may be needed to recheck electrolytes, liver or kidney values.