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Feline Upper Respiratory Viruses - Part Three:
Panleukopenia IntroductionThis is the third in a series of articles to explain the nature of the disease viruses that are contained within the routine vaccines typically administered at nine and 12 weeks of age. The purpose is to help the reader understand each virus that is included, what it does, how cats get infected, what is done to treat it and how to avoid or manage it. This article deals with the virus called Panleukopenia, a parvovirus which causes severe infections virulent enough to warrant inclusion of the vaccine in a regular vaccination schedule. In addition, upper respiratory viruses can occur at the same time as a Panleukopenia infection. Panleukopenia is known and referred to by a multitude of names and symbols in literature. Authors assume the reader knows that they mean the same thing. There are so many that the following is a list in order of those most frequently used (the first three listed) followed by those less frequently used:
In this article the virus will be referred to as Panleukopenia. What is Panleukopenia?Panleukopenia is an infection so severe that it was referred to as "Cat Plague" in earlier times when infections would nearly wipe out cat populations in certain geographical areas. It is a highly contagious, severe parvovirus that causes enteric (bowel), immune system and nervous system disease. This parvovirus is very small and hardy, with several strains that affect not only domestic cats and kittens, but any felid - such as lions, bobcats and tigers. It is important to be aware of this disease as the fatality rate in susceptible cats/kittens is 50-90%. What does Panleukopenia Virus Do?A) Active DiseasePanleukopenia virus affects three major body systems in the cat. The system it chooses is dependent on the age of the cat at time of infection.
Blood/Lymphatic SystemPanleukopenia virus will attack and destroy white blood cells in cats. This is a VERY TYPICAL finding with this virus, and the degree of WBC depression is used as an indication as to the severity of the infection. This destruction of WBCs is called "leukopenia" - "Leuk" meaning WBCs and "penia" meaning a reduced number. The more severe the leukopenia the poorer the prognosis for that individual. The steady decline of white blood cells begins about three days after infection, and by the fourth to the sixth day it may be hard for the veterinarian to find them at all in a blood sample. Through the suppression of WBCs the immune system is also severely depressed. 100% of cats/kittens that are infected with Panleukopenia. Gastrointestinal SystemThe first symptom is a fever, with depression and lack of appetite, which lasts about 24 hours. The temperature will return to normal for a short period before rising very high again, with severe depression, vomiting, no appetite and rapid dehydration, followed later by diarrhea. These symptoms can vary from none at all in healthy adults to full high fever and sudden death in kittens. If death does not occur rapidly (with the first temperature increase), then the second time the fever rises depression will be severe and the cat/kitten will lay with its head dropped between its legs and belly to the floor (VERY TYPICAL). Often these cats/kittens will also hang their heads above the water bowl. Diarrhea usually follows the second fever's rise, but in many fatal cases, the cat/kitten does not make it to this stage. If a cat/kitten is older than 16 weeks and survives the first 48 hours, the chances of recovery are much improved. If death still has not occurred in five to seven days, then recovery is rapid with proper care. Mortality is up to 90% in kittens less than six months old. Older cats are more resistant, but death rates can approach 50% in susceptible adults as well. If a female is infected with Panleukopenia virus while she is pregnant, she can abort, or give birth to stillborn kittens or mummified fetuses, and it can result in permanent infertility afterwards. What happens to the kittens in utero is explained under "Nervous System" effects of Panleukopenia. Nervous SystemWhen a female is infected with Panleukopenia virus for the first time while pregnant, it affects not only her (as discussed above) but the kittens she is carrying as well. If the infection occurs in the first stages of pregnancy, then the effect on the kittens will likely be abortion, resorption and stillbirth. If the infection occurs during the last trimester of the prenatal period and up to two weeks after birth, the rapidly reproducing cells of the cerebellum of the kittens will be infected (remember that this virus likes rapidly reproducing cells). The area of rapid cell growth at this time is a certain germinal layer of the brain (cerebellum) AND the retinal cells of the eye. Kittens affected this way show no signs of their affliction until they begin to walk and become mobile, at which time they experience difficulty walking, turning and keeping their balance, swaying while standing with legs wide apart and tail high to help keep balance. Kittens show exaggerated movements and head twitching and may fall to either side easily. This ataxia (lack of proper balance) and abnormal movement is generally non-progressive, but may seem so, as it takes until three to four weeks of age to become evident. As mobility increases in these affected kittens, they will show more completely the extent of the ataxia they will have for the rest of their lives. Severity of SymptomsAs with other feline viruses, how many of the above signs a cat gets, and to what degree, is dependent on many things, all of which are important.
B) Latent and "Carrier" DiseaseA "carrier" or "latent" stage for Panleukopenia generally does not occur, with most cats not shedding the virus in body secretions beyond three weeks of active disease. Only an occasional cat who survives previous infection (and has gone through the active phase of the disease) will carry the virus up to one year, thus truly representing a carrier cat. Virus shedding cats for Panleukopenia are usually in the active phase of the disease and can spread virus to the environment and other cats. How are Cats Infected with Panleukopenia?Cats must come in contact with the Panleukopenia virus to become infected. This virus must be taken in internally through the eyes, nose or mouth.
Panleukopenia virus is an extremely hardy virus and survives most temperatures and disinfectants. It is possible for a cat to get infected both directly and indirectly at the same time, but the hardiness of the virus makes both ways equally infective. The cat who is shedding virus could have done so a long time before the next cat comes across it and becomes infected as well.
The worst shedders of viruses are cats/ kittens currently ill with the virus. Due to the ability of the virus to survive so well in extreme temperatures in the environment, the infective secretions from these cats can be present for up to 13 months at ideal (room) temperature. Also, common environmental contamination both indoors and out can be assured due to the resistance of the virus to all disinfectants BUT bleach. How is Panleukopenia Diagnosed?Most veterinarians will diagnose Panleukopenia based on the clinical symptoms they see, the history prior to illness (including vaccination) and a total WBC count from a blood sample. How is Panleukopenia Treated?A cat/kitten sick with Panleukopenia virus requires mostly supportive care for the symptoms it produces, as it is a virus infection. Strict isolation is essential to reduce the environmental contamination. Veterinarians will often prescribe antibiotics as well, but only because they wish to avoid the resulting bacterial infections that happen in conjunction with the damage from the virus infection. Supportive care is dependent upon which symptoms and which form of the disease was produced.
How can Panleukopenia be Prevented?Prevention of Panleukopenia is the easiest part of handling this disease. Since vaccines were developed for this virus, the number of cats affected by this condition has dwindled to nearly nothing. The virus is still out there, however, carried by unvaccinated cats, both indoors and out.
SummaryAlthough there is much more to the subject of vaccination and its effect on this disease, this article will hopefully increase the understanding about Panleukopenia, what it can do and why it is important for those who have cats (especially those with groups of cats) to respect its effects on the general health of felines. References:
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