Annotated Bibliography

Panleukopenia Outbreak Case Review
An Annotated Bibliography with Shelter-Medicine Implications
Kelly Cyr, DVM, MS

Introduction:
Feline panleukopenia virus (FPV) is a highly contagious disease that can be especially difficult to manage in animal shelters due to its high morbidity rate in unvaccinated cats, its ability to remain infectious in the environment for long periods leading to easy fomite spread, and its resistance to many common disinfectants. Even with good management, panleukopenia outbreaks can occur in a shelter setting. The purpose of this bibliography is to synthesize information about the panleukopenia virus itself, the course of disease it causes, methods of diagnostic testing, and methods of managing outbreaks to in order to determine the best course for preventing and managing FPV outbreaks in animal shelters.

Annotated Bibliography

Abd-Eldaim, M., Beall, M. J., & Kennedy, M. A. (2009). Detection of feline panleukopenia virus using a commercial ELISA for canine parvovirus. Veterinary Therapeutics: Research in Applied Veterinary Medicine, 10(4), E1-6.

This study evaluated the accuracy of Idexx’s Canine Parvovirus SNAP ELISA test at identifying panleukopenia in the stool of symptomatic cats. This study compares SNAP Parvovirus results with panleukopenia PCR results, which are generally more sensitive, on samples from 97 cats with clinical signs sins of panleukopenia. 54 out of 55 cats who were panleukopenia positive on PCR were also positive on SNAP Parvovirus, indicating that in this study there was a 96% agreement in results between Idexx’s Canine Parvovirus SNAP ELISA and PCR. This study will be useful in guiding my recommendations for testing of cats to diagnose panleukopenia, especially in the face of an outbreak as the Idexx Canine Parvovirus SNAP ELISA tests are relatively inexpensive and generate results within minutes.

Bergmann, M., Schwertler, S., Speck, S., Truyen, U., Reese, S., & Hartmann, K. (2019). Faecal shedding of parvovirus deoxyribonucleic acid following modified live feline panleucopenia virus vaccination in healthy cats. Veterinary Record, 185(3), 83–83. https://doi.org/10.1136/vr.104661

This study evaluated fecal shedding of FPV virus following MLV vaccination in 40 cats on days 7, 14, 21, and 28 mainly via PCR with sequencing being performed on positive cases to determine if the strain isolated was vaccine or wild-type. While studies have been done on fecal parvovirus shedding in dogs after MLV vaccination, this was the first study looking at panleukopenia shedding in cats following MLV vaccination. This study found that fewer cats (7.5%) shed virus after MLV vaccination that had been found in dogs (23%). Though the sample size was small, and there was no control group, they theorize that cats may shed less virus after vaccination than dogs. This will be useful for my project, specifically when designing protocols for diagnosing FPV in cats before and during an outbreak. A If fecal shedding of FPV is low following vaccination, then theoretically they are also less likely to be positive on antigen ELISA SNAP tests, making positive results on these bedside tests more reliable.

Crawford, C. (2021). Canine and Feline Parvovirus Infections in Shelters. UF Maddie’s Shelter Medicine Program. https://sheltermedicine.vetmed.ufl.edu/wordpress/files/2022/03/Canine-and-Feline-Parvovirus-Infections-in-Shelters.2021-2.pdf

This guideline provides recommendations about feline parvovirus clinical features, diagnosis, management, and prevention of FPV in shelters. One big takeaway is the discussion on diagnosing parvovirus, especially where it’s stated that Idexx SNAP Parvo tests have been shown to not detect vaccine strain and that PCR can result in a higher rate of vaccine induced false positives. We had a lot of PCR positive cats in this outbreak with high Ct values and no clinical signs, I suspect for many of these cats the positive PCR was vaccine induced. Another is the information about managing the disease when infections occur, especially quarantining exposed animals but not testing unless they show clinical signs. This source is the shelter medicine graduate program that I am currently enrolled in, I trust that it is relevant to shelter medicine best practices.

DiGangi, B. A., Gray, L. K., Levy, J. K., Dubovi, E. J., & Tucker, S. J. (2011). Detection of Protective Antibody Titers against Feline Panleukopenia Virus, Feline Herpesvirus-1, and Feline Calicivirus in Shelter Cats Using a Point-of-Care ELISA. Journal of Feline Medicine and Surgery, 13(12), 912–918. https://doi.org/10.1016/j.jfms.2011.07.009

This study looked to assess the accuracy of feline point of care ELISA tests (VacciCheck) for FPV, FHV, and FCV for determining protective antibody titers (PAT) to these viruses. It also looked at accuracy of a canine point of care ELISA (TiterCHEK) specifically for determining antibody levels to FPV, as this had been previously recommended. The study evaluated samples from 356 adult cats and compared results on these tests to results on a gold standard test (hemagglutination inhibition assay (HI)). This study found that the canine ELISA is not sensitive at detecting PAT to FPV. It found that the feline ELISA is highly specific (99%) but not highly sensitive (49%), thus this tests resulted in a lot of false negatives, but very few false positives. In the event of a FPV outbreak, this tool could be useful in determining PAT in cats in order to help place cats into risk categories. Cats with positive PAT on point of care ELISA are likely to be true positives. This test will, however, result in a high number of false negatives, leading to some cats with PAT being incorrectly assigned to a higher risk category and held for longer than necessary.

Dykstra, A. (n.d.). Managing a Feline Panleukopenia Outbreak in a Shelter [Webinar]. Retrieved July 4, 2026, from university.maddiesfund.org/webinar/189275

This webinar on Maddie’s University website details a feline panleukopenia virus (FPV) outbreak in a municipal shelter in rural Appalachia that the presenter. This webinar goes through the outbreak from start to finish, including information about the shelter itself, information about the outbreak, information about how they choose to divide cats into risk categories and otherwise manage the outbreak given the limited resources they had, and how the outbreak concluded. This kind of real-life experience managing an outbreak will be very helpful for me when making decisions about how I would recommend that the outbreak my presentation is about should have been handled.

Feline Panleukopenia. (2023, August 9). [Guidebook]. UC Davis Koret Shelter Medicine Program. https://www.sheltermedicine.com/library/resources/feline-panleukopenia/

This guidebook goes over feline panleukopenia virus recommendations for shelters, including diagnosis, quarantining, treating, reintroducing infected cats, and cleaning/disinfection. The section on risk assessment will be important for me when going through what I think we should have done when managing cats when this outbreak occurred. The information on diagnostics will also be helpful for me to create a plan for how to diagnose panleukopenia in individual cats moving forward and for how to diagnose cats during an outbreak situation. This source is the UC Davis Koret Shelter Medicine Program, which has a multitude of guidebooks for other common shelter diseases aside from panleukopenia, thus I trust this source and do not find it to be biased

Fuller, E., & DiGangi, B. (2025). Treatment and Outcomes of Sheltered Cats with Feline Panleukopenia using Canine Parvovirus Monoclonal Antibody (CPMA) [Abstract]. Journal of Shelter Medicine and Community Animal Health, 4(1). https://doi.org/10.56771/jsmcah.v4.132

This abstract (not peer reviewed) is for a study evaluating the use of Canine Parvovirus Monoclonal Antibody (CPMA) in the treatment of Feline Panleukopenia (FPV) in cats. This study compared 31 cats diagnosed with FPV and not treated with CPMA and 24 cats diagnosed and treated with CPMA. They found that the median time to discontinuation of treatment for cats treated with CPMA was 3.5 shorter than for cats not treated with CPMA. They also found no adverse effects from the administration of CPMA. Their conclusion is that CPMA may be helpful in treating panleukopenia in shelter cats. This is something I would consider adding to my protocol for treatment of FPV in cats.

Jacobson, L. S., Janke, K. J., Giacinti, J., & Weese, J. S. (2021). Diagnostic testing for feline panleukopenia in a shelter setting: A prospective, observational study. Journal of Feline Medicine and Surgery, 23(12), 1192–1199. https://doi.org/10.1177/1098612X211005301

This prospective, observational study sought to determine the best method for diagnosis of FPV in shelters. They compared Idexx Parvovirus SNAP test and quantPCR results, and evaluated results on samples taken from vomit and rectal swabs. This study found that the SNAP test had lower sensitivity (77%) than previous studies (94%), but found that even faint positives on SNAP test were positive on quant PCR. They did not have enough samples of vomit/rectal swabs to make conclusions. This further supports my choice to include Idexx Parvovirus SNAP tests as an initial diagnostic tool for FPV detection in general and during an outbreak situation.

Janke, K. J., Jacobson, L. S., Giacinti, J. A., & Weese, J. S. (2022). Fecal viral DNA shedding following clinical panleukopenia virus infection in shelter kittens: A prospective, observational study. Journal of Feline Medicine and Surgery, 24(4), 337–343. https://doi.org/10.1177/1098612X211023056

This prospective, observational study aimed to determine how long cats with FPV in a shelter setting specifically shed virus in their stool after initial infection. Historically, studies on this have only been done in experimentally infected cats not in a shelter setting, and they theorize that the stress of a shelter setting could prolong shedding time. This study initially included 40 cats and kittens, with a medial age of 5 weeks at the time of diagnosis, but was only able to follow 16 kittens through the full 14 days, and 12 kittens through to 21 days. Of the 16 kittens they followed to 14 days, they found that one was positive via quantPCR on day 14, and one was SNAP faint positive, quantPCR negative. On day 21 all kittens were negative on SNAP and PCR. This study suggests that clinically significant virus shedding is unlikely after 2 weeks following diagnosis, which is shorter than other previous studies have suggested. This will be useful for my capstone when making recommendations about how long to continue quarantine of positive cats following diagnosis.

Litster, A., & Benjanirut, C. (2014). Case series of feline panleukopenia virus in an animal shelter. Journal of Feline Medicine and Surgery, 16(4), 346–353. https://doi.org/10.1177/1098612X13497738

This retrospective study evaluated records from 145 cats in an “adoption guarantee” shelter who were either in contact with FPV positive cats (66 cats), survived FPV infection (27 cats), or died from FPV (52 cats). They compared these cats signalment, and history (including vaccination history), clinical signs, and length of time from development of clinical signs to resolution or death. The most important conclusions for my purposes are that protective immunity to FPV cannot be assumed to be present in adult cats, since 30% of their FPV survivors and 15% of their FPV fatalities were adults. This information will help in my capstone when determining how to create risk categories. They also found that 100% of FPV positive cats experiencing circulatory shock died, which will be useful in my study when creating guidelines about which cats to treat.

Miller, L., Janeczko, S., & Hurley, K. F. (2021). Infectious disease management in animal shelters (2nd ed). Wiley Blackwell.

This textbook provides recommendations for management of infectious disease in animal shelters. I plan on using the recommendations in the Feline Panleukopenia Section (Chapter 15) and the Outbreak Management section (Chapter 6) to make many of my recommendations for management of FPV and FPV outbreaks.

Neuerer, F. F., Horlacher, K., Truyen, U., & Hartmann, K. (2008). Comparison of different in-house test systems to detect parvovirus in faeces of cats. Journal of Feline Medicine and Surgery, 10(3), 247–251. https://doi.org/10.1016/j.jfms.2007.12.001

This prospective study evaluated 5 commercially available tabletop parvovirus tests to try to determine the accuracy of each test. Out of a total of 52 cats with diarrhea, 10 had feline panleukopenia virus (FPV) confirmed via electron microscopy. All of the tests had relatively high negative predictive values (NPV) (>97%), and the Witness Parvo test, the SNAP Parvo test, and the Speed Parvo test all had positive predictive values of 100%. This study recommended the Fastest Parvo Strip test because of it’s high NPV, but the study also states that this test had a higher number of false positives and “seemed to have a higher sensitivity than electron microscopy”, which may mean that the test actually was giving more false positives. Based on this and other papers, I will recommend using the Idexx Parvo SNAP test for initial diagnosis of FPV.

Newbury, S., & Hurley, Kate F. (2025, April 16). Neonatal Vaccination Recommendations. University of Wisconsin-Madison Shelter Medicine School of Veterinary Medicine. https://sheltermedicine.wisc.edu/neonatal-vaccination-recommendations/

This is an article on the University of Wisconsin-Madison School of Veterinary Medicine’s Shelter Medicine website about updated recommendations for neonatal vaccination in shelter animals. This article argues that kittens <4 weeks of age who are in a shelter setting and at high risk of exposure to panleukopenia should be vaccinated as early as possible as part of a shelter’s method to prevent disease in kittens. These recommendations are based on a summary of different literature looking at things like antibody levels in animals entering a shelter, vaccination of human neonates, vaccination of puppies at about 2 weeks of age, and information about neonatal immunology. Their conclusion is that the risk from disease is far greater than the risks from vaccination in neonates, thus they recommend neonatal vaccination. Unfortunately, there aren’t any major studies cited or apparently available that look specifically at the effects of vaccination in neonates.

Patterson, E. V., Reese, M. J., Tucker, S. J., Dubovi, E. J., Crawford, P. C., & Levy, J. K. (2007). Effect of vaccination on parvovirus antigen testing in kittens. Journal of the American Veterinary Medical Association, 230(3), 359–363. https://doi.org/10.2460/javma.230.3.359

This is a prospective controlled study aimed at evaluating Feline Panleukopenia Virus (FPV) vaccine interference with fecal parvovirus tests in cats. This study selected 64 kittens, check their parvovirus titers and a stool test prior to vaccinating to confirm that they were negative. They then vaccinated them with one of 8 different vaccines (two inactivated and six MLV), then used different tabletop parvovirus test daily for 15 after vaccination. The Idexx Parvovirus SNAP test yielded only 1 positive results. The AGEN CPV test produced 4 positive results and the WITNESS CPV test produced 13 positive results. Because of these results, I’d be most likely to recommend utilizing the Idexx Canine Parvovirus SNAP test for screening of cats to avoid the risk of vaccine interference.

Porporato, F., Horzinek, M. C., Hofmann-Lehmann, R., Ferri, F., Gerardi, G., Contiero, B., Vezzosi, T., Rocchi, P., Auriemma, E., Lutz, H., & Zini, E. (2018). Survival estimates and outcome predictors for shelter cats with feline panleukopenia virus infection. Journal of the American Veterinary Medical Association, 253(2), 188–195. https://doi.org/10.2460/javma.253.2.188

This retrospective cohort study of 265 shelter cats who presents to an animal hospital for presumptive treatment of FPV aimed to look at both FPV survival outcomes and indicators for survival vs. death from FPV. They found that cats with a higher body weight (<2.75lbs) had a higher likelihood of survival (sensitivity 69.6%, specificity 64.6%). They also found that cats who were lethargic were 6 times more likely to die than those that weren’t, and that those with a rectal temperature of 100.2F or higher were more likely to survive than those with lower temps (sensitivity 100%, specificity 39.6%). They found no correlation between lab results (including CBC) at intake and survival, but did find that cats who survived had higher leukocyte counts at 72hrs 96hrs, and 7 days. They also found that the chance of dying decreased with the use of amoxicillin-clavulanic acid (65%), anti-parasitic drugs (87%), and maropitant (84%). The results of this study will be useful for my capstone when determining what treatments to include for positive cats, and what variable to include when making euthanasia decisions about FPV positive cats.

Rehme, T., Hartmann, K., Truyen, U., Zablotski, Y., & Bergmann, M. (2022). Feline Panleukopenia Outbreaks and Risk Factors in Cats in Animal Shelters. Viruses, 14(6), 1248. https://doi.org/10.3390/v14061248

This study compares 4 separate shelters, 3 experiencing FPV outbreaks and one not experiencing a FPV outbreak with the goal of determining what the risk factors are for FPV outbreaks to occur in animal shelters. They looked at a large number of variables, including MLV vaccination vs. use of hyperimmune serum, animal age, husbandry, whether or not shelters shut down for intake, disinfection/cleaning, etc. They found that unvaccinated cats were 47 times more likely to develop FPV than unvaccinated cats when faced with an outbreak. They also found that age was very important, with cats <2 years old being 72 times more likely to develop FPV than cats >2 years of age. This fits with other recommendations that vaccination prior to or immediately upon admission to a shelter is critical for prevention of FPV during an outbreak, and will shape my recommendations in my own presentation when it comes to the importance of vaccinating all cats at intake for FPV both to prevent in-shelter transmission and in the event of an outbreak.

The Association of Shelter Veterinarians. (2020). Position Statement: Depopulation (Version 1) [Position Statement]. The Association of SHelter Veterinarians. https://www.sheltervet.org/assets/docs/Depopulation.pdf

The consensus of the ASV is that depopulation is not an appropriate response to a disease outbreak and should only be done as a last resort after consulting with a veterinarian with experience in outbreak management. This position statement, by the ASV who also published the Guidelines for Standards of Care in Animal Shelters, will support my stance that in the future, we should not euthanize healthy animals and should consult other veterinarians as soon as possible if we feel like we need help responding to future outbreaks.


The Association of Shelter Veterinarians. (2022). The Guidelines for Standards of Care in Animal Shelters: Second Edition. Journal of Shelter Medicine and Community Animal Health, 1(S1), 1–76. https://doi.org/10.56771/ASVguidelines.2022

This foundational document outlines standards for all aspects of animal shelter functioning as it relates to animal care and housing. In its section on disease outbreaks, it states that relevant protocols should be reviewed to ensure that they are appropriate for the pathogen that is suspected, which is not what happened in the FPV outbreak I was part of. It also takes the opinion that depopulation should be a last resort and not an initial response. These opinions are important in the creation of an outbreak management protocol like the one I plan on creating for my capstone.



Conclusion

These sources demonstrate the importance of management in prevention of feline panleukopenia outbreaks in animal shelters, especially the importance of early vaccination. They also demonstrate the high risk that kittens in particular face from this virus, in many of these studies the majority of FPV positive cats are less than 3 months of age. They also demonstrate that point of care tests, such as the Idexx Canine Parvovirus SNAP test and the VacciCheck titer test can be used to screen for panleukopenia or for the presence of protective antibodies respectively, though studies show that both tests are likely to produce false negatives. Some studies also show varying sensitivity and specificity with these tests, especially in recently vaccinated cats. Resources specifically on success of specific FPV treatment methods are lacking and often inconclusive, indicating that more research needs to be done to determine which treatment strategies are most effective. Combined, these resources can shape recommendations for FPV outbreak prevention and management, and for making decisions about who and how to treat FPV in a shelter setting.