ANCILLARY DIAGNOSTIC WORK-UP FOR INDIVIDUAL DOGS
THE DIAGNOSTIC WORK-UP
This can provide important information in making treatment decisions.
- A complete blood count (CBC) with differential, serum biochemistry profile, urinalysis, thoracic radiographs, and cultures can all provide helpful information. The CBC may be normal, or show mild leukopenia consistent with viral infection; however, leukocytosis (neutrophilia) with or without a left shift may indicate that the dog is developing pneumonia.
- Thoracic radiograph findings may range from mild bronchointerstitial infiltrates to consolidation of all lung lobes.
- Secondary bacterial infection may be identified by cultures performed on nasal swabs from dogs with purulent nasal discharge, or on transtracheal and endotracheal washes of dogs with pneumonia. Potential pathogens include a variety of gram-positive and gram-negative bacteria, including Staphylococcus spp., hemolytic and nonhemolytic Streptococcus spp., Pasteurella multocida, Klebsiella pneumoniae, Escherichia coli, and Mycoplasma spp.
- Antibiotic therapy can be targeted based on culture and sensitivity results.40
SEROLOGY
Serology to detect CIV-specific antibodies is the most reliable diagnostic test for confirmation of canine influenza infection.
- This testing should be performed in conjunction with other tests to confirm virus presence.
- CIV-specific antibodies can be detected in a hemagglutination inhibition assay as early as 7 days post infection; however, reliable detection occurs after 10 days of clinical signs.40,44
It is important to note that a negative antibody titer for serum samples collected before day 10 does not rule out CIV infection. In addition, because the presence of antibodies only indicates exposure but not necessarily active infection, it is necessary to compare an acute titer with a titer taken at least 2 weeks later (a convalescent titer) to confirm a four-fold or greater rise in antibody titer (seroconversion) in order to prove that there was a recent active infection.