Comparison of three laboratorial tests for diagnosis of canine parvovirus infection / Comparação de três testes laboratoriais para diagnóstico da infecção pelo parvovírus canino

The aim of this study was to evaluate the rapid tests currently used for canine parvovirus (CPV) diagnosis: hemagglutination test (HA), enzyme immunoassay (EIA) and polymerase chain reaction (PCR). A total of 112 fecal samples collected from diarrheic puppies up to one year of age were tested. The EIA was able to detect CPV antigen in 44 samples. By HA, 32 samples tested highly positive with titers >128, eight tested weakly positive (titers 32 and 64) and 72 were negative (titers <16). Using PCR, 57 samples were found positive including 13 EIA-negative and 19 HA-negative samples. The best correlation was observed between EIA and PCR (88.4%). These tests were able to detect all types of CPV, including CPV-2c. Considering that 23%-33% of dogs presenting enteritis did not show infection by EIA nor HA, negative results from the antigen detection tests should be confirmed through molecular methods.(AU)

Avaliaram-se os métodos rápidos rotineiramente utilizados para diagnóstico da infecção por parvovírus canino (CPV): teste de hemaglutinação (HA), ensaio imunoenzimático (EIE) e reação em cadeia pela polimerase (PCR). Um total de 112 amostras fecais de cães diarreicos com até um ano de idade foi testado. O EIE foi capaz de detectar o antígeno do CPV em 44 amostras. Por HA, 32 amostras foram consideradas fortemente positivas com títulos >128, oito fracamente positivas (títulos 32 e 64) e 72 negativas (títulos <16). Por PCR, 57 amostras foram positivas incluindo 13 EIE-negativas e 19 HA-negativas. A melhor correlação foi observada entre EIE e PCR (88,4%). Os testes foram capazes de detectar todos os tipos de CPV, incluindo o CPV-2c. Considerando-se que em 23%-33% dos filhotes com enterite a infecção por CPV não foi diagnosticada pelos testes de EIE e HA, os resultados negativos nos testes de detecção de antígeno devem ser confirmados por meio de métodos moleculares.(AU)

Partial VP2 sequencing of canine parvovirus (CPV) strains circulating in the state of Rio de Janeiro, Brazil: detection of the new variant CPV-2c

Canine parvovirus (CPV) is the most important enteric virus for dogs and it seems to be undergoing continuous evolution, generating new genetic and antigenic variants throughout the world. The aim of this study was to analyze the distribution of CPV variants from 1995 to 2009 and to investigate the circulation of the new variant CPV-2c in Rio de Janeiro, Brazil. In addition, the clinical features of CPV infection were also reported. After CPV laboratorial confirmation by HA/HI and PCR, thirty-two fecal samples were analyzed by sequencing a 583-bp fragment of the VP2 gene. One sample, collected in 2008 was typed as the new type CPV-2c. All samples from 1995 to 2003 were identified as "new CPV-2a". From 2004 to 2006, both "new CPV-2a" and CPV-2b were observed. From 2006 to 2009, most of the samples were characterized as CPV-2b. The classical signs of CPV enteritis were observed in 16/18 CPV-2a and 5/13 CPV-2b infected puppies. These results show that continuous epidemiological surveillance of CPV strain distribution is essential for studying the patterns of CPV-2a and 2b spread and for determining whether the new variant CPV-2c has become permanently established in Brazilian canine population.