Chapter 3: Recognition and Diagnosis

Clinical Signs include:

• Vomiting
• Diarrhea
• Dehydration
• Lethargy
• Sudden death/found dead in cage 

Diagnosis may include: 

• Clinical signs and exposure history.
• Positive results on an IDEXX brand Parvo SNAP test.
  • False negatives may occur more commonly than when using these tests for canine parvo (one small study found 20-50% false negatives on various brands).²
  • False positives were rare in this same study, occurring 0-6% of tested samples depending on brand of test.²
  • Vaccine induced positives were rare on the IDEXX brand test (only 1/64 recently vaccinated kittens tested positive on an IDEXX brand test; other brands had a higher rate of positive results following vaccination.³
• Low white blood cell count on CBC or blood smear.
• Segmental enteritis observed on necropsy.
• PCR at a diagnostic laboratory (1-3 day turnaround time often possible)
  • Can be useful to confirm or rule out infection when results of the above tests are giving mixed results 
  • Negative results in correctly collected and transported samples are reliable to rule out infection 
  • Positive results may occur in recently vaccinated cats; laboratories (e.g. Idexx) may provide quantitative results to help distinguish probable vaccine from true infection
• During an outbreak, log all test results in a central location, including age, date of shelter entry, date of test, and location of cat.

Population Monitoring

Although diagnostic tests are quite effective to confirm or rule out FPV infection, this must go hand in hand with daily or more frequent monitoring of the population. If an unthrifty animal goes undetected for hours or days, the opportunity for spread is hugely magnified.

• Noticing, isolating and testing sick cats ASAP will help stop spread.
• During an outbreak, have trained, designated staff check all cats at least twice daily.
• Provide written instructions detailing what to do when a possible case is recognized:
  • Who to contact
  • What diagnostics to perform (SNAP test, blood smear, etc.)
  • What to do with the cat
  • How to clean the cage and other areas the cat accessed and possibly contaminated
  • What to do with exposed cats
• In addition to the daily walk-throughs, ALL staff and volunteers should be trained to recognize possible signs of FPV and what to do when they see any of the clinical signs.
• It is particularly important that staff look over all cats for clinical signs of FPV prior to cage cleaning, to prevent spread during cleaning.

For more information on population monitoring, refer to Instructions for daily monitoring for health and behavior and Daily Shelter Rounds.