Epizootiological Investigation Of Canine Coronavirus

Canine coronavirus (CCV) is one of the main pathogen of canine gastroenteritis. It was first isolated from the feces of military dogs with diarrhea in Germen in 1971. A novel CCV genotype strain were reported recently in the world. In China, the prevalence of CCV was first confirmed in 1985, but no systematic epizootiology investigation had been done.Here, a coinfection in dogs with CCV and canine adenovirus (CAV), causing 86 dogs gastroenteritis and leading to 21 dogs death, was identified by physiochemical method, in virulence to inculcated animals, electron microscopy, and PCR. CCV and CAV were isolated from diarrhea dogs, passaged on MDCK cell line, respectively. The CAV wild strain was identified type II CAV by a typing assay PCR, and designated CAV2-KM. A 218bp fragment of M gene of the CCV wild strain designated CCV-KM was sequenced and analyzed. The results revealed that CCV-KM shared the highest(95.3%) similarity with the FCoV-like CCV strain detected in Italy.40 faecal samples of fatal dogs collected since 2000 and 137 faecal samples of healthy dogs collected from Dec. 2003 to Apr. 2004 from different cities were tested for the presence of CCV using a nested-PCR. The results showed that the total positive ratio of CCV in fatal dogs samples was 20% (8/40) . Among 8 CCV positive samples, five were co-infected with other viruses. While, in healthy dogs group from three cities, CCV positive ratio in Kunming group (93.1%, 27/29) was higher than that of in Nanjing (73.1% , 38/52) and Shenyang (87.2%, 34/39) groups. There were significance differences between different age groups, the percnetage of CCV detection in pups was 89.5% in 2 month-old group and 85.1% in 3-12 month-old group, higher.than that in older dogs (57.1%). In Nanjing group, seventeen dogs were detected two times interval two months, the presence of CCV in feces and neutralizing antibody level showed no significance difference.