08/20/2024
ALERT: ASYMPTOMATIC PARVOVIRUS WITH SUDDEN DEATH
This post is intended to alert wildlife rehabilitators about a strain of parvovirus which impacted the Animal Institute's Wildlife Clinic this past week, despite our strict adherence to clinical safety protocols and best practices, including intake quarantine, vaccination, and deep cleaning / pathogen elimination to prevent cross-contamination.
This strain of parvovirus is almost entirely asymptomatic, and does not present typical gastrointestinal symptoms. Lethargy is the primary symptom, and it only presents hours before death. The patient may tuck its head in a body position similar to what is often observed during initial distemper infection. One patient exhibited soft gelatinous excrement, but that was an exception case. No other symptoms were observed in any patient. Within hours after lethargy is initially observed, the patient suffers sudden death.
This parvovirus is remarkable in part because the victim goes from an apparently healthy disposition to death within hours, in a very rapid progression. Due to the virus's largely asymptomatic nature, it is difficult to detect or identify. A parvovirus antigen test will positively identify the infection, even after death via an intra-anal swab, but because the infection does not present as typical parvovirus, one may not think to conduct a parvovirus antigen test.
This parvovirus is also resistant to vaccination, and will cause sudden death in vaccinated animals. In our experience, it takes a minimum of two parvovirus vaccinations to ensure an immune response sufficient for survival.
The largely asymptomatic nature of this parvovirus makes initial detection and diagnosis very difficult - a pathogenic ghost. Should you suspect its presence, we encourage you in the strongest terms to react immediately with a crash protocol consisting of isolation, parvovirus treatment protocols, cleaning with a disinfectant sufficient to kill parvovirus (e.g. Virkon S), and the immediate administration of a parvovirus booster vaccination to every animal in your facility. Do not wait! You have no time to lose! Any death resulting from an unidentified condition should be evaluated as potential parvovirus.
We further recommend administering a parvovirus antigen test on intake for every single animal that comes into your facility, regardless of symptoms presented, and a reevaluation of the sufficiency of your intake isolation and pathogen elimination protocols.
This scientific abstract was useful in understanding what we were facing:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8546482
The Massachusetts facility referenced in the abstract above lost eight of their nine juvenile raccoons to this parvovirus in 2019. This past week we were able to rapidly identify the cause of our own event, despite its nearly invisible nature, which limited our deaths to two juvenile raccoons and one adult raccoon. While it was incredibly heartbreaking to lose them, in the scheme of things we were fortunate not to lose many more.
I want to thank several people for their advice, guidance, and support:
• Dr. Justin & Cassie Verner of the the Sweetwater Creek Animal Hospital, who were the first to suggest it might be parvovirus, despite the lack of supporting symptoms. Theirs was a truly brilliant insight!
• Vet tech Kacee Peterson for quickly finding the scientific abstract above, which enabled me to understand the nature of this parvovirus within the initial hours.
• Wildlife rehabilitators Jackie Wilcox and Christine Hunt for their superb guidance and support throughout this past week.
Care and treatment of injured, ill, and orphaned raccoons, foxes, coyotes, skunks, bobcats, and bats.
