Efficacy of feline serum transfusion for prevention or reduction of disease in panleukopenia exposed kittens

Last updated: 2020-06-15
Author: Dr. Emily Pellatt
Document type: FAQs
Topic: Infectious Disease
Species: Feline

There is no evidence that serum transfusion from an adult vaccinated cat changes clinical disease in unvaccinated panleukopenia exposed kittens.


In one of your online resources/publications regarding feline panleukopenia virus, it states that, "Passive protection from serum transfusion has been shown in puppies exposed to canine parvovirus. Therefore, it may be that in exposed, unvaccinated kittens, 2 ml of serum from an immune cat given SC or intraperitoneal soon after exposure may provide some protection."

This references the Greene textbook, from which I found the sentence where it, too, states that this might be a therapy for exposed but healthy, unvaccinated kittens.

A wonderful foster/rescue group with whom I used to work reached out to me and asked me about this. I'd like to help them and to provide accurate information. Do you know of veterinarians and/or shelters that have used serum from vaccinated, healthy adult cats as such? If so - what type of dosing would one use? - just 2ml? One time only? Or multiple days? Preference for SQ vs IP? The kittens that this foster/rescue organization has are approx. 6 weeks old, unvaccinated (until today), otherwise healthy and happy, but exposed to panleuk from another now-deceased kitten with whom they had resided.

Thank you for your help and insights!!


Thanks for reaching out to us. We’ve reviewed the supporting evidence for using serum in unvaccinated kittens and are re-evaluating our guideline as a result.

Unfortunately, there is minimal scientific research supporting the use of serum to prevent or reduce illness associated with parvovirus. A study on the efficacy of feline antiparvoviral serum in parvovirus puppies found that while the serum neutralized the virus in vitro there was no effect on clinical signs, shedding, mortality, or time to recovery(1). In light of this, the clinical effectiveness of serum treatment is questionable.

In addition to a lack of evidence for efficacy of the treatment, the time and labor involved for staff is considerable and the risk of adverse reactions cannot be eliminated as with any other transfusion. Serum transfusions should not be used in place of vaccination and other management strategies which prevent underage and unvaccinated kittens from exposure to panleukopenia as well as other transmissible diseases.

Vaccination for kittens at 4 weeks of age is our best protection against panleukopenia. In the absence of maternal antibodies, kittens begin to mount immunity against panleukopenia immediately on vaccination and develop sterile immunity by 3 days. Vaccine guidelines for panleukopenia can be found here.

Other considerations when working with unvaccinated kittens include managing admissions to keep these kittens with their mothers and out of shelters until they are old enough to be vaccinated, or ideally big enough (e.g. 1.5 pounds) to undergo surgery and be adopted. If kittens do need to be admitted to the shelter, immediately placing them in foster homes and never mixing kitten litters can help minimize disease exposure and provide more enrichment and socialization as well as less environmental stress than in the shelter.

In situations such as the one you mention, where kittens have already been exposed to panleukopenia or other transmissible diseases, it is important to separate healthy exposed kittens from their sick littermates to minimize further transmission, and separate exposed and sick kittens from unexposed kittens to minimize the possibility of transmission.

By keeping kittens out of shelters, utilizing foster homes, starting kitten vaccines at 4 weeks old and separating litters of kittens we can minimize disease transmission risk, improve welfare and provide a better environment until these kittens are ready for adoption.

Please let us know if you have any further questions and thank you for bringing this guideline to our attention so that we could improve our available resources.

University of Wisconsin Shelter Medicine Program

Emily Pellatt, DVM
Maddie’s Shelter Medicine Intern 
Shelter Medicine Program
University of Wisconsin – School of Veterinary Medicine


(1) - Gerlach, M., et al. "Efficacy of feline anti‐parvovirus antibodies in the treatment of canine parvovirus infection." Journal of Small Animal Practice 58.7 (2017): 408-415.

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