Genetic and antigenic characterization of recombinant nucleocapsid proteins derived from canine coronavirus and canine respiratory coronavirus in China

Lu, Shuai; Chen, Yingzhu; Qin, Kun; Zhou, Jianfang; Lou, Yongliang; Tan, Wenjie

Coronaviruses are enveloped, positive-stranded RNA viruses that are highly prevalent in animal and human populations (Woo et al., 2009) . To our knowledge, six types of coronaviruses have been recognized to be pathogenic to humans: HCoV-NL63, HCoV-229E, HCoV-OC43, SARS-CoV, HCoV-HKU1 and MERS-CoV. Because of the high mutation frequency and broad host ranges of this virus, novel coronaviruses have emerged and evolved to cross species during the past decade, generating novel strains, serotypes and genotypes. Canine coronavirus (CCoV) and canine respiratory coronavirus (CRCoV) are common viral pathogens responsible for mild to severe enteritis or respiratory symptoms in dog populations (Nicola and Canio, 2008) . CCoV infection was first reported in a German military dog with diarrhea in 1971 (Binn et al., 1974) . Since then, CCoV has been determined to be epidemic globally, and dogs of all breeds and ages appear to be susceptible to infection (Costa et al., 2014; Erles and Brownlie, 2009; Lorusso et al., 2009; Naylor et al., 2002; Yachi and Mochizuki, 2006) . In China, CCoV was isolated from the heart and gastrointestinal contents of a sick dog for the first time in 1995 (Kong, 2007) , and identified in deceased giant pandas in 2009 (Gao et al., 2009) . In 2003, a novel respiratory coronavirus (CRCoV) distinct from CCoV was detected from the respiratory tracts of diseased dogs in the UK (Erles et al., 2003) . Currently, CRCoV is found in dogs in Europe as well as Asia (Lorusso et al., 2009; Yachi and Mochizuki, 2006) .