Proksch A L, Unterer S, Speck S, Truyen U, Hartmann K
Clinic for Small Animal Medicine, Centre for Clinical Veterinary Medicine, Ludwig-Maximilians-Universität Munich, Veterinaerstrasse 13, 80539 Munich, Germany.
Clinic for Small Animal Medicine, Centre for Clinical Veterinary Medicine, Ludwig-Maximilians-Universität Munich, Veterinaerstrasse 13, 80539 Munich, Germany.
Vet J. 2015 Jun;204(3):304-8. doi: 10.1016/j.tvjl.2015.03.009. Epub 2015 Mar 16.
False negative faecal canine parvovirus (CPV) antigen ELISA results in dogs with CPV infection are common, but the factors that lead to these false negative results are still unknown. The aim of this study was to investigate whether dogs with a false negative faecal CPV antigen ELISA result have milder clinical signs and laboratory changes, a lower faecal virus load, higher faecal and serum CPV antibody titres and a faster recovery than dogs with a positive result. Eighty dogs with CPV infection, confirmed by the presence of clinical signs and a positive faecal CPV polymerase chain reaction (PCR), were assigned to two groups according to their faecal antigen ELISA result. Time until presentation, severity of symptoms, laboratory parameters, faecal virus load, faecal and serum antibody titres, and CPV sequencing data were compared between both groups. In 38/80 dogs that were hospitalised until recovery, the time to recovery, mortality, and the course of the disease were compared between dogs with positive and negative faecal antigen ELISA results. Of the 80 dogs included, 41 (51.3%) had a false negative faecal antigen ELISA result. ELISA-negative dogs had a significantly shorter time until presentation, lower frequency of defaecation, lower faecal virus load, and higher serum antibody concentrations than ELISA-positive dogs. Laboratory changes, CPV shedding, and outcomes were not associated with faecal antigen ELISA results. In conclusion, low faecal CPV load and antibodies binding to CPV antigen in faeces are likely to be important reasons for false negative faecal antigen ELISA results. Dogs with clinical signs of CPV infection should be retested by faecal PCR.
犬细小病毒（CPV）感染犬只粪便抗原ELISA结果出现假阴性很常见，但导致这些假阴性结果的因素仍不清楚。本研究的目的是调查粪便CPV抗原ELISA结果为假阴性的犬只与结果为阳性的犬只相比，临床症状和实验室变化是否更轻微、粪便病毒载量是否更低、粪便和血清CPV抗体滴度是否更高以及恢复是否更快。根据粪便抗原ELISA结果，将80只经临床症状和粪便CPV聚合酶链反应（PCR）阳性确诊为CPV感染的犬只分为两组。比较两组之间的就诊时间、症状严重程度、实验室参数、粪便病毒载量、粪便和血清抗体滴度以及CPV测序数据。在38只住院直至康复的犬只中，比较粪便抗原ELISA结果为阳性和阴性的犬只的恢复时间、死亡率和病程。在纳入的80只犬只中，41只（51.3%）粪便抗原ELISA结果为假阴性。ELISA阴性犬只的就诊时间明显更短、排便频率更低、粪便病毒载量更低，血清抗体浓度高于ELISA阳性犬只。实验室变化、CPV排毒情况和预后与粪便抗原ELISA结果无关。总之，粪便中CPV载量低以及抗体与粪便中CPV抗原结合可能是粪便抗原ELISA结果假阴性的重要原因。有CPV感染临床症状的犬只应通过粪便PCR进行重新检测。
