Molecular stability of a vaccine strain of Canine coronavirus after serial passages in A72 cells / Estabilidade molecular de uma amostras vacinal de Coronavírus canino após passagens seriadas em células A72

Canine coronavirus (CCoV) exists in types I and II and infects dogs leading mainly to enteritis, though type II has already been associated with generalized and highly lethal infection. A CCoV-type II inactivated vaccine produced in A72 canine cells is available worldwide and largely used, though the molecular stability after serial passages of vaccine seeds is unknown. This article reports the evolution of the CCoV-II vaccine strain 1-71 in A72 cells based on partial S gene sequencing, showing the predominance of neutral evolution and the occurrence of four sites under purifying selection. Thus, cell-adapted strains of CCoV-II may be genetically stable after serial passages in a same cell line due to a stable virus-host relationship.(AU)

O Coronavírus canino (CCoV) ocorre como tipos I e II e infecta cães, levando principalmente a enterite, apesar do tipo II já ter sido associado à infecção generalizada e altamente letal. Uma vacina de CCoV-II inativada produzida em células caninas A72 é disponível mundialmente e largamente utilizada, apesar da sua estabilidade molecular após passagens seriadas de sementes vacinais ser desconhecida. Este artigo relata a evolução da amostra vacinal CCoC-II 1-71 em células A-72 com base em sequenciamento parcial do gene S, demonstrando predomínio de evolução neutra e a ocorrência de quaro sítios sob seleção purificante. Portanto, amostras de CCoV-II adaptadas a cultivos celulares podem ser estáveis geneticamente após passagens seriadas em uma mesma linhagem celular devido à existência de uma relação estável vírus-hospedeiro.(AU)

M gene analysis of canine coronavirus strains detected in Korea

The purpose of this study was to investigate the genetic features of canine coronavirus (CCV) strains detected in Korea. M gene sequences obtained for isolates from 22 dogs with enteritis over a 5-year period were evaluated. Sequence comparison revealed that the 22 Korean CCV strains had an 87.2 to 100% nucleotide homology. Comparing to the typical reference CCV strains (type II), the nucleotide sequence of Korean strains had homology ranged from 86.3% to 98.3% (89.1% to 99.2% for the amino acid sequence) and 87.7% to 97.8% (92.4% to 100% for the amino acid sequence) when compared to FCoV-like CCV strains (type I). Three amino acid variations in the M gene were characteristic for the Korean CCV strains. Phylogenetic analysis demonstrated that the 22 Korean CCV strains belonged to four typical CCV clusters (i.e., a unique Korean CCV cluster, a type II and transmissible gastroenteritis virus cluster, an intermediate cluster between type I and II, and a type I cluster). This study was the first to identify genetic differences of the M gene from Korean CCV strains and provided a platform for molecular identification of different Korean CCV strains.

Effect of the ethanolic extract from green propolis on production of antibodies after immunization against canine parvovirus (CPV) and canine coronavirus (CCoV) / Efeito do extrato etanólico de própolis verde sobre a produção de anticorpos após imunização contra parvovírus canino (CPV) e coronavírus canino (CCoV)

This study was designed to evaluate whether an ethanolic extract of green propolis (EEP) can interfere with p roduction of specific antibodies after immunization against parvovirus (CPV) and canine coronavirus (CCoV). Mice were vaccinated with CPV and CCoV (0.75, 1.5 and 3 x 106 TCID50) with or without 400 μg/dose of the EEP. Twenty one days after the third dose was measured serum IgG. The co-administration of the EEP significantly enhanced serum specific IgG responses to CPV in animals inoculated with the highest concentration of the antigen, and had no influence on levels of antibodies to CCoV. The results indicate that the EEP has immunomodulatory action closely dependent on the type and concentration of antigen used, being able to increase the levels of antibodies to CPV.

Este estudo foi realizado para avaliar se extrato etanólico de própolis verde (EEP) pode interferir na produção de anticorpos específicos após imunização contra parvovírus (CPV) e coronavírus canino (CCoV). Camundongos foramvacinados com CPV e CCoV (0.75, 1.5 e 3 x 106 TCID50) com ou sem 400 μg/dose de EEP. Vinte e um dias após a terceira dose foi mensurado IgG sérica. A coadministração de EEP aumentou significativamente os níveis de IgG específica para o CPV em animais inoculados com a maior concentração do antígeno, e não teve influência sobre os níveis de anticorpos para CCoV. Os resultados indicam que o EEP tem ação imunomoduladora intimamente dependente do tipo e concentração do antígeno utilizado, sendo capaz de aumentar os níveis de anticorpos contra CPV.

Exposure of pampas fox (Pseudalopex gymnocercus) and crab-eating fox (Cerdocyon thous) from the Southern region of Brazil to Canine distemper virus (CDV), Canine parvovirus (CPV) and Canine coronavirus (CCoV)

The exposure of 13 Brazilian free-ranging nondomestic canids (five pampas fox - Pseudalopex gymnocercus and eight crab-eating fox -Cerdocyon thous) from Southern region of Brazil, to Canine distemper virus (CDV), canine parvovirus (CPV) and Canine coronavirus (CCoV) was investigated. Antibodies against CDV were detected in 38.5 percent (5/13) of the samples. There were anti-CDV antibodies in 60 percent (3/5) of P. gymnocercus and in 25 percent (2/8) of C. thous. The frequency was higher among the adults and males. Eleven canids (84.6 percent) presented antibodies against CPV, 80 percent (4/5) were from P. gymnocercus and 87.5 percent (7/8) were from C. thous. There was no difference in positivity rate against CPV between gender and age. Antibodies against CCoV were detected in 38.5 percent (5/13) of the samples, with 60 percent (3/5) of positivity in P. gymnocercus and 25 percent (2/8) in C. thous. The frequency of antibodies against CCoV was higher among the adults and males. The study showed that these canids were exposed to CDV, CPV and CCoV.

Foi investigada a ocorrência de exposição em 13 canídeos não domésticos de vida livre (cinco graxains-do-campo - Pseudalopex gymnocercus e oito graxains-do-mato - Cerdocyon thous) da região sul do Brasil ao vírus da cinomose canina (CDV), parvovírus canino (CPV) e coronavírus canino (CCoV). Anticorpos contra o CDV foram detectados em 38,5 por cento (5/13) das amostras. Haviam anticorpos anti-CDV em 60 por cento (3/5) dos P. gymnocercus e em 25 por cento (2/8) dos C. thous. A freqüência foi maior entre machos e adultos. Para CPV, 11 canídeos (84,6 por cento) apresentaram anticorpos, 80 por cento (4/5) eram da espécie P. gymnocercus e 87,5 por cento (7/8) eram C. thous. Não houve diferença de positividade para o CPV entre sexos e idades. Anticorpos contra o CCoV foram detectados em 38,5 por cento (5/13) das amostras, sendo 60 por cento (3/5) de positividade entre os P. gymnocercus e 25 por cento (2/8) entre os C. thous. A freqüência de anticorpos para CCoV foi maior entre os machos e adultos. O estudo revelou que estes canídeos foram expostos ao CDV, CPV e CCoV.

Isolation and identification of a canine coronavirus strain from giant pandas (Ailuropoda melanoleuca)

Two giant pandas (Ailuropoda melanoleuca) died of unknown causes in a Chinese zoo. The clinical disease profile suggested that the pandas may have suffered a viral infection. Therefore, a series of detection including virus isolation, electron microscopy, cytobiological assay, serum neutralization and RT-PCR were used to identify the virus. It was determined that the isolated virus was a canine coronavirus (CCV), on the basis of coronavirus, neutralization by canine anti-CCV serum, and 84.3% to 100% amino acid sequence similarity with CCV. The results suggest that the affected pandas had been infected with CCV.