Comparing PCR and rapid test for diagnosing parvovirus in dogs

Abstract

Canine parvovirus type 2 (CPV-2) is one of the most common viruses responsible for acute hemorrhagic enteritis in dogs. A rapid and accurate diagnosis of CPV-2 infection is especially important in kennels in order to isolate infected dogs. The aim of the present study was to compare two laboratory tests i.e., Polymerase Change Reaction (PCR) and Immunochromatography assay (ICA) most commonly used for the diagnosis of canine parvovirus infection in companion dogs. Fecal samples were collected from fifty five dogs (50=hemorrhagic diarrheic and 5= healthy) between 2011 and 2012 in Ahvaz district, southwest of Iran. The studied dogs were divided into two age groups (<6 months, and>6 months), four different breeds (Terriers, German shepherds, Doberman pinschers and Mixed) and based on environment into two groups (open and close) also. All samples were tested by ICA and PCR methods and the results were analyzed by using Kappa test, Mc Nemar and Chi-square analysis. ICA and PCR were able to detect CPV-2 antigen or nucleic acid in 33 and 50 of the hemorrhagic diarrheic samples, respectively. Samples of healthy dogs were negative by both tests. Although sensitivity of ICA compared with PCR method was determined to be 66% (PCR more sensitive than ICA), nevertheless statistical analysis showed that the difference between two techniques were not significant (P>0.05). Kappa test was obtained 0.38 between two techniques. CBC showed that most infected dogs had leucopenia, lymphopenia and neutropenia also (82%; 41 out of 50 samples).Obtained results of this survey showed that accurate standardization of laboratory tests is required to provide veterinarian with an effective tool for a precise etiological diagnosis of hemorrhagic gastroenteritis due to CPV infection. Although Immunochromatography is a simple and quick method for screening of fecal samples of dogs suspected of CPV infection, but PCR is more sensitive and reliable than ICA. Moreover, the subtypes of the virus determined by PCR test after verifying parvovirus. In this test 48 samples were CPV-2b and another 2 samples were CPV-2a. Our results showed that CPV-2b was the predominant subtype.