Parvo and panleukopenia: a shelter perspective (Proceedings)
Canine parvo and feline panleukopenia are closely related viruses that replicate in rapidly dividing cells. The most obvious symptoms of infection are gastrointestinal but the bone marrow is also affected. The virus is transmitted primarily by the fecal-oral route (including indirectly via objects/clothing/hands contaminated with virus from feces). These viruses are unenveloped making them very durable persisting in the environment for months or even years. The incubation period is generally less than 14 days, on average 5-7 days. It tends to be shorter in cats. Control in shelters is dependent on effective vaccination, accurate and efficient diagnosis, effective isolation, and careful cleaning and disinfection. This lecture will focus on these four key outbreak control tools.
Effective shelter vaccination
Vaccination for parvo viruses is highly effective if performed correctly. Shelter vaccination protocols can substantially reduce spread of infection as they are more intensive than those used in private practice. This fact has been recently recognized by both the American Association of Feline Practitioners (AAFP) and the American Animal Hospital Association (AHAA) published vaccine guidelines. Modified live subcutaneous vaccination will provide considerably more rapid protection than killed vaccines. All cats and dogs 4-5 weeks of age and older should receive a modified live parvo/panleukopenia vaccine immediately upon shelter entry. Studies have shown that parvo vaccines can illicit protective immunity within 3-5 days of vaccination in susceptible dogs1. Panleukopenia vaccines have been shown to protect against disease within 72 hrs of exposure. Even injured, pregnant and mildly ill animals should be vaccinated, unless they are certain to be euthanized within a few days.The emergence of a new canine parvo strain (CPV-2c) has elicited concern about the efficacy of current parvo vaccines that use either CPV-2 or CPV-2b strains. The research and conclusions remain controversial to date but most evidence suggests that all currently available parvo vaccines do protect against CPV-2c
1) Carmichael, L. E., J. C. Joubert, et al. (1983). "A modified live canine parvovirus vaccine with novel plaque characteristics. 1. Viral attenuation and dog response." Cornell Vet 73(1): 13-29.
2) Brun et al. Immunisation against panleukopenia: early development of immunity. Comp Immunol Microbiol Infect Dis. 1979;1(4):335-339.
3) Spibey et al., Veterinary Microbiology 128 (2008) 48–55
4) Larsen et al., Do two current canine parvovirus type 2 and 2b vaccines provide protection against the new type 2c variants. Vet Therap., 2008 9(2):94-101.
Risk assessment and quarantine