FPV Has a Guarded Prognosis

Vaccinations help but are not 100% effective

I lost a 6.5-month-old, fully vaccinated kitten to panleukopenia. Everything I have read about panleukopenia says that fully vaccinated kittens should be protected, but we have lost several that have fit that description. I have been volunteering in animal rescue for over 12 years and  have never seen it this bad. Everyone is diligent about vaccination and cleaning and disinfection, but it seems to be everywhere this year. Do you know if there is anything different about panleukopenia this year?

I am sorry to hear of your recent loss and the other cats this year. Panleukopenia is a serious viral infection  and, while I am not aware of any specific differences in viral strains and/or outcomes of infection this year compared to previous years, this is the subject of ongoing research. Perhaps a review of how the virus infects and causes disease and some recommendations to minimize the possibility of infection would help.

Feline panleukopenia virus (FPV, also known as “feline parvovirus”) is a type of parvovirus that is similar but distinct from canine parvovirus (although it is capable of infecting dogs). It is passed in the urine, feces, and nasal secretions of most infected cats for a relatively short time after they are infected (i.e., one to two days) and is relatively resistant to disinfection by most commonly used products. It can survive in the environment for up to one year.

An important point here is that susceptible cats may still become infected by environmentally accumulated virus even after thorough disinfection protocols have been carried out. For this reason, only fully vaccinated cats should be allowed to enter such an environment, and strict isolation of infected cats is essential to prevent infection.

Replication of the virus in infected cats occurs only in tissues that are actively undergoing growth, so organ systems such as the gastrointestinal (GI) tract, the lymphoid tissue that is partially responsible for the production of white blood cells, and the bone marrow in which red blood cells, white blood cells, and platelets are produced (all of which are constantly metabolically active) are affected.

Cats that are infected may show a variety of signs, including diarrhea, vomiting, anemia, low white blood cell counts (predisposing to other infections), abortions in pregnant queens, and neurologic signs in kittens that have been infected in utero.

There is no definitive cure for FPV, and treatment is primarily supportive. The restoration and maintenance of hydration, prevention of bacterial infections using antibiotics, restoration of red blood cells and proteins via transfusion, prevention of blood clot formation, and assurance of adequate nutrition are all vital to providing the best outcomes.

Unfortunately, even in FPV-infected cats that are managed optimally, the prognosis for cats infected by FPV is guarded at best. More than 50% of cats diagnosed will succumb to their infections, and up to 90% of kittens will not survive their infections.

Prevention through vaccination is still the best way to provide cats with their best outcomes when it comes to FPV, although no vaccine works 100% of the time. Interestingly, a recent study found that cats that did not receive at least one of their initial kitten series of FPV vaccines at greater than 12 weeks of age were more likely to succumb to FPV than those that did.

It is also of interest that the Cornell Feline Health Center is currently funding research focused on investigating the prevalence of strains of FPV that may evade immune protections provided by vaccination through the introduction of mutations that alter the proteins that vaccine-induced antibodies recognize as part of their virus-neutralizing effects. We will be sure to inform the public of the findings of these studies as soon as we become aware of them.

I’d suggest making sure that strict isolation and decontamination protocols be followed with any cats that are found to be infected with FPV, and that, until we know more, you try to ensure that all kittens have received at least one of their initial series of FPV vaccines at greater than 12 weeks of age.