Reliability of clinical diagnosis and laboratory testing techniques currently used for identification of canine parvovirus enteritis in clinical settings

FAZ, Mirna; MARTÍNEZ, José Simón; QUIJANO-HERNÁNDEZ, Israel; FAJARDO, Raúl

During clinical examination, variability in clinical manifestations of infection was observed. Only 20% of the studied dogs presented typical signs as commonly described in literature. Clinical variability for this disease has been reported previously [2, 4, 7, 10, 15, 18] , and some authors have discussed factors, such as age, immune status, exposure route, viral dose, virulence of strains and co-infection with other infectious agents as possible causes [4, 15, 18] . This complicates obtaining an accurate diagnosis of CPV-2 when veterinarians rely solely on their clinical examination. Therefore, regarding our investigation solely based on this procedure, 42.2% of dogs will have a false-negative CPV-2 diagnosis.Through dogs medical records in this study, we observed that veterinarians were ruling out the possibility of infection primarily because the dogs were not exhibiting the classical clinical signs described in literature, had been vaccinated against CPV-2 and/or were adults. However, most of the dogs in our study displayed atypical signs. Therefore, we believe that subclinical infections of CPV-2 are more common, and veterinarians, who must decide whether or not to use additional diagnostic tests with high sensitivity and specificity, should seriously consider these findings. --+ ---+ + 35 + -+ + + --+ + 36 --+ + ---+ + 37 --+ + -+ --+ 38 Nd --+ + ---+ 39 + -+ -+ ---+ 40 + -+ + -+ --+ 41 Nd In this study, 40% of patients positive to CVP-2 had been previously immunized. It is well known that PCR technique is highly sensitive, and therefore, it detects vaccine viral particles in feces from recently vaccinated patients; studies indicate that it is possible to obtain false-positive results from days 3 to 10 post-vaccination with a modified live CPV vaccine [10, 18] . Consequently, to perform this study, patients with history of vaccination on the previous 15 days were excluded. Additionally, samples from vaccinated dogs positive to CPV-2 were sequenced, and in all studied cases, the genovariant CPV-2c was identified (data not show), which implies that dogs were infected with field CPV-2c, knowing that no CPV-2c vaccine is available yet in Mexico. Moreover, in Mexico, Pedroza and colleagues reported that the most common antigenic variant in infected dogs was CPV-2c [16] .