Mary Allen
The cat disease, also called parvovirus, is a serious and life-threatening infectious disease, especially for young animals and unvaccinated cats. There is a very effective, well-tolerated vaccination against parvovirus, but not all cats are vaccinated with it. The disease is therefore still widespread.
Pathogen
Parvovirus is a viral infection caused by feline panleukopenia virus (FPV) in cats. In addition to FPV, cats can also become infected with CPV-2a and -2b, the canine parvovirus that is actually specific to dogs. None of the viruses mentioned can be transmitted to humans and therefore infection is not possible.
The virus multiplies in rapidly dividing cells of the host animals. In addition to the small intestine cells (crypt cells), these also include cells of the lymphatic system (spleen, thymus) and bone marrow cells.
The parvoviruses are highly stable and extremely resistant. The viruses can only be killed by special disinfectants. For example, the viruses can survive in the feces at room temperature for at least 6 months and be contagious. Strong acids or bases are no problem for them, they tolerate a pH range of 3 to 11 and survive temperatures of 70°C for more than 30 minutes.
Transmission
Infected cats shed large amounts of virus in their feces. Infection occurs through ingestion of feces, fodder contaminated with feces, and objects such as toys or clothing. Unborn kittens can also get the virus from their mother.
Young animals and unvaccinated or insufficiently vaccinated cats are primarily at risk. As a rule, newborn kittens do not get sick because they are protected by antibodies from the mother. However, these antibodies do not last indefinitely – the young animals can still become ill if they have not yet built up their own immunity.
In cats, there is no known breed predisposition. However, other factors such as worm infestation, FeLV or coronavirus (FIP) infection, and being in larger groups of animals (large kennels, homes, etc.) can also promote infection in cats.
Course Of Infection
After ingestion of infected feces, the virus first affects the lymph nodes in the pharynx and the tonsils. From there, the infection spreads to the lymphatic tissues of the thymus and intestines and then throughout the body. As a rule, the virus can already be detected in the intestinal cells after 4 days, from which point virus excretion begins. On the other hand, the incubation period (= the time from infection to the appearance of the first symptoms) is usually 7-14 days. Other animals can therefore be infected by cats that are not yet showing any symptoms and are therefore not perceived as sick cats. In total, as the virus is excreted for about 14 days, rarely longer.
Symptoms
The course of the disease is usually acute, but with fairly unspecific symptoms. Affected cats exhibit inappetence, anorexia, apathy, and fever, followed by vomiting and diarrhea. Diarrhea can be very serious. The feces may contain digested (melena) or fresh blood. In rare cases, there are also very peracute courses of parvovirus, in which sudden death occurs without previous diarrhea.
Due to the sometimes massive diarrhea, the cats suffer a high level of fluid and electrolyte loss. An additional refusal of food and water intake very quickly leads to severe dehydration up to volume deficiency shock. In addition, the immune system is weakened because the parvovirus destroys progenitor cells of red and white blood cells. This results in anemia (anemia) and a lack of white blood cells (leukopenia). Blood loss through blood in the feces and increased consumption of immune cells in the intestine further aggravate the situation.
The viruses lead to the destruction of the affected cells in the small intestine. An additional weakening of the immune system means that intestinal bacteria and toxins (poisons) can enter the bloodstream unhindered. The resulting blood poisoning (septicemia, endotoxemia) and colonization of bacteria in other organs (e.g. lungs, liver) can have fatal consequences.
If a cat becomes infected in the womb or during the neonatal period, the puppies will develop cerebellar hypoplasia (underdevelopment of the cerebellum). The affected animals show non-progressive neurological symptoms of varying severity. Inflammation of the heart muscle (myocarditis) has also been described in perinatal infections, which can lead to acute or chronic heart failure.
Diagnosis
The diagnosis is based on general parameters such as age, vaccination status, origin, etc., clinical symptoms (vomiting, diarrhea), blood values that show a significant reduction in white blood cells (leucopenia), and virus detection in the feces. Rapid tests can be carried out in almost every veterinary practice, which provides results within a short time. In the case of a positive test result, the statement is quite reliable. However, false-positive results also occur if vaccination with live vaccines has taken place within the previous 2 weeks. Unfortunately, even a negative test result does not rule out an infection with 100% certainty. Neutralizing antibodies in the feces, which bind the virus, or the only temporary excretion of the virus are known sources of error. Antibody detection in the blood or molecular biological detection methods (PCR) is used to check vaccination protection. Finally, the parvoviruses can be found in the feces by means of an electron microscopic examination, which is not universally available.
Treatment
Viruses are fundamentally difficult to treat, and there is currently no specific antiviral therapy for the feline disease. Strict hygiene measures and separating the sick cat from other animals have top priorities. To compensate for fluid and electrolyte loss through vomiting and diarrhea, the animals need intravenous infusions. Broad-spectrum antibiotics are given to prevent the spread of bacteria. Furthermore, symptomatic vomiting and pain are treated with medication. Since damage to the intestinal wall also means that a great deal of protein is lost, special infusion solutions (colloidal solutions) often have to be administered to prevent the formation of edema. A particularly important part of therapy is enteral nutrition as early as possible. Force-feeding the sick cat or even feeding it through a tube is usually necessary because the affected patients usually do not eat independently. Immune preparations are also part of the standard therapy. A transfusion of blood products or whole blood is necessary if the cat has lost a lot of blood through the feces and has anemia. Finally, deworming medication should be administered as soon as patients stop vomiting.
Complications
The problem is the loss of protein through the damaged intestinal wall, which can lead to the formation of edema and/or fluid effusions in the body cavities. The loss of protein also limits the comprehensive infusion therapy that is actually necessary, although this is very important for balancing fluids and electrolytes. Intestinal invaginations, which can also occur as part of the cat epidemic, usually require surgical intervention. However, the most feared complications are certainly septicemia and DIC (= disseminated intravascular coagulopathy, a life-threatening condition in which excessive blood clotting in the vascular system leads to the consumption of coagulation factors and thus to an increased tendency to bleed).
Prognosis
The prognosis is very individual and depends, among other things, on age, race, the presence of concomitant infections, the immune status, and the occurrence of complications. In any case, the therapy, whether and how the affected animal is treated, has a major influence on the prognosis. While only about 10% of cats survive without treatment, survival rates of 90% and more are achieved with intensive care (inpatient) therapy.
Prophylaxis
Vaccination is the only way to protect your cat from infection. The causative virus is ubiquitous and extremely resilientBecause the virus is ubiquitous and highly resilient, the only way to protect your pet from infection is through vaccination. In its guidelines, the StIKo Vet (Standing Vaccination Commission for Veterinary Medicine) calls the parvovirus vaccination in dogs and cats a core component, i.e. one against which every animal must be protected at all times. The current recommendation for vaccination includes primary immunization with vaccination at the age of 8, 12, and 16 weeks of life and a repeat at the age of 15 months of life. Thereafter, booster vaccinations are recommended every 3 years. The more frequent vaccinations in the first months of life are due to the presence of maternal antibodies. These prevent successful vaccination (i.e. development of protective immunity) by neutralizing the vaccine virus. Since the number of maternal antibodies and thus the duration of their presence is usually unknown, additional vaccinations are necessary. After the 16th week of life, however, no more maternal antibodies are to be expected.