Canine parvovirus 2 (CPV2) is the most common strain of parvovirus seen today—specifically variants CPV2a and CPV2b. In her presentation "Canine parvovirus type: Does it impact prevention, diagnosis or prognosis?" Julie K. Veir, DVM, PhD, DACVIM, discussed a new variant: CPV2c.1
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Cases of CPV2c infection were reported as far back as 2001 in Italy. In 2006 and 2007, CPV2c infection began to be reported in the United States.
CAN CURRENT PARVO TESTS DETECT THIS VARIANT?
Field strains of CPV2c may cause false negative results on point-of-care testing, and reasons for this remain unclear. False positive results due to recent parvovirus vaccination have also been noted. False negative test results may occur because of differences in antigen or antibody binding or perhaps shorter duration of shedding in the feces. If this is true, then the timeline of when testing is performed during the course of the disease could affect the results.
Dr. Veir discussed quantitative PCR testing as one methodology that may help document a true infection. However, availability, cost, and turnaround time may hinder its utility.
Dr. Veir said point-of-care tests are specific, but not particularly sensitive. So even if its test results are negative, a patient strongly suspected of having parvovirus infection (based on signalment and clinical signs) could still have the infection and should be treated appropriately. There is no conclusive evidence to date documenting that the strain of parvovirus has any impact on prognosis or that vaccine failure will lead to widespread CPV2c infection in the canine population.
1. Veir JK. Canine parvovirus type: Does it impact prevention, diagnosis, or prognosis? Presented at the Annual Meeting of the American College of Veterinary Internal Medicine; June 2012.
This "Lecture Link" summary from the 2012 American College of Veterinary Internal Medicine Forum was contributed by Jennifer L. Garcia, DVM, DACVIM, a veterinary internal medicine specialist at Sugarland Veterinary Specialists in Houston, Texas.
Dr. Jennifer L. Garcia