Hong Charles, Decaro Nicola, Desario Costantina, Tanner Patrick, Pardo M Camila, Sanchez Susan, Buonavoglia Canio, Saliki Jeremiah T
Athens Veterinary Diagnostic Laboratory, University of Georgia, Athens, GA 30602, USA.
J Vet Diagn Invest. 2007 Sep;19(5):535-9. doi: 10.1177/104063870701900512.
Canine parvovirus (CPV) type 2 (CPV-2) emerged around 1978 as a major pathogen of dogs worldwide. In the mid-1980s, the original CPV-2 had evolved and was completely replaced by 2 variants, CPV-2a and CPV-2b. In 2000, a new variant of CPV (named CPV-2c) was detected in Italy and now cocirculates with types 2a and 2b in that country. The CPV-2c has also been reported from single outbreaks in Vietnam and Spain. This study was conducted to determine if CPV-2c occurs in the United States. Thirty-three fecal samples were collected from dogs in 16 states between April 2006 and April 2007 and were tested for CPV using real-time polymerase chain reaction (PCR). Positive samples were further tested using conventional PCR and minor-groove binding TaqMan PCR assays to determine the viral type and to differentiate vaccine strains from field strains. Twenty-seven samples were positive for CPV, 7 of which were CPV-2c from 5 states: Arizona, California, Georgia, Oklahoma, and Texas. Of the 7 isolates, 4 differed from European CPV-2c isolates by 2 additional single-nucleotide mutations at positions 4076 and 4104, the latter of which produces a ThrAla change at residue 440 located near a major antigenic site. The coast-to-coast geographic distribution of the states in which CPV-2c was detected strongly suggests that this new CPV variant is probably widespread in the United States. The continuous evolution of CPV requires that monoclonal antibody-based and nucleic acid-based diagnostic assays should be periodically checked for sensitivity on prevalent CPV strains.
犬细小病毒2型（CPV-2）于1978年左右出现，成为全球犬类的主要病原体。20世纪80年代中期，原始的CPV-2发生了进化，完全被两种变体CPV-2a和CPV-2b所取代。2000年，在意大利检测到一种新的CPV变体（命名为CPV-2c），目前在该国与2a型和2b型共同流行。在越南和西班牙的单次疫情中也报告了CPV-2c。本研究旨在确定CPV-2c是否在美国出现。2006年4月至2007年4月期间，从16个州的犬只中收集了33份粪便样本，并使用实时聚合酶链反应（PCR）检测CPV。对阳性样本进一步使用常规PCR和小沟结合TaqMan PCR检测，以确定病毒类型，并区分疫苗株和野毒株。27份样本CPV呈阳性，其中7份来自亚利桑那州、加利福尼亚州、佐治亚州、俄克拉何马州和得克萨斯州5个州的CPV-2c。在这7株分离株中，有4株在第4076和4104位发生了另外2个单核苷酸突变，与欧洲CPV-2c分离株不同，后者在位于一个主要抗原位点附近的第440位残基处产生了苏氨酸到丙氨酸的变化。检测到CPV-2c的各州从东海岸到西海岸的地理分布强烈表明，这种新的CPV变体可能在美国广泛存在。CPV的持续进化要求定期检查基于单克隆抗体和基于核酸的诊断检测对流行CPV毒株的敏感性。
