Diagnostic Tests for Feline URI Pathogens

Since FHV and FCV cause 80-90% of Feline URI cases in shelter cats, there is no advantage to testing URI cats to confirm these pathogens. However, the shelter should invest in diagnostic testing when:

• Cats have severe clinical disease, including pneumonia
• Cats have more severe ocular signs
• Cats are coughing
• Duration of illness is more prolonged

Consider Chlamydia felis infection in cats with ocular disease only, and Bordetella infection in cats that are coughing or have pneumonia. Cats with severe clinical disease, including pneumonia, may be co-infected with Strep zoo.

The best diagnostic test is PCR for pathogen nucleic acid on swabs. PCR is very sensitive and specific. The turnaround time for results is usually 2-3 business days which allows for timely patient and population management. Several diagnostic laboratories offer Feline URI PCR panels that test for multiple viral and bacterial respiratory pathogens in a single sample. Test costs range from $90 to >$120 per sample. IDEXX offers a substantial discount on their Feline URI PCR panel for shelters. IDEXX also offers the most comprehensive Feline URI PCR Panel that includes identification of any influenza A virus and Strep zoo.

Sites to swab include the caudal pharyngeal wall beyond the tongue. For cats suspected to have Chlamydia felis infection, the conjunctiva should also be swabbed. These sites should be rubbed with the swab tip to collect infected epithelial cells. At least 2 swabs should be collected from each cat and pooled together to maximize the probability of pathogen detection. To increase diagnostic accuracy and identify a pattern, swabs should be collected from at least 5 cats with clinical signs. The more cats that are tested, the more confident you can be in the test results, especially if there is a consistent pattern of results.