Onchocerca lupi is an emerging zoonotic parasite of dogs, endemic to the southwestern USA and areas of the Old World. Currently, there are no specific serological diagnostic tests able to detect O. lupi infection. Recent literature has demonstrated that commercially available heartworm antigen tests, despite being highly sensitive, may cross-react with infections by other filarid nematodes. There is no information on potential cross-reactivity of such tests in serum of dogs infected with O. lupi. Our objective was to assess serum samples of dogs naturally-infected with O. lupi for potential cross-reactivity before and after heat-treatment using a commercial heartworm ELISA kit. We obtained serum from 23 dogs naturally-infected with O. lupi. These dogs presented with ocular disease, and were consulted to schedule either surgical removal of ocular nodules due to infection or enucleation. Samples were tested in triplicate using the DiroCHEK® Heartworm Antigen Test kit (Synbiotics Corporation, Zoetis, Kalamazoo, MI, USA) following the manufacturers' protocol pre- and post-heat-treatment. Samples were heat-treated using a dry heat block at 103 °C for 10 min and then centrifuged at 1818×g for 20 min. Out of a total of 23 dogs, 19 (82.6 %) had no antigen detected regardless of heat-treatment, three dogs tested positive before and after heat-treatment, and a single dog turned positive after heat-treatment. These three dogs that were positive before and after heat-treatment were confirmedly co-infected with Dirofilaria immitis by the veterinarians responsible for these cases, and we were unable to get the history or follow up with the dog that turned positive post-heat-treatment only. Our data suggest that O. lupi infections should not result in false-positives when using the DiroCHEK® in dog serum, before or after heat-treatment. Dogs with clinical ocular onchocercosis that test antigen-positive in DiroCHEK® are likely co-infected with D. immitis, and should be further tested, including evaluation of microfilariae in blood and diagnostic imaging. If heartworm infection is confirmed, the animals should be enrolled in the recommended treatment protocol in accordance to the guidelines of the American Heartworm Society or other local organizations.

中文翻译：

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使用市售的心丝虫ELISA试剂盒评估来自自然感染了Onchocerca lupi的狗的血清的潜在交叉反应性。

Onchocerca lupi是一种新兴的人畜共患寄生虫，在美国西南部和旧世界地区特有。当前，没有能够检测到O. lupi感染的特异性血清学诊断测试。最近的文献表明，尽管市售的心丝虫抗原检测灵敏度很高，但可能与其他丝状线虫的感染发生交叉反应。没有关于这种测试在被O. lupi感染的狗的血清中可能发生交叉反应的信息。我们的目标是使用商业性的心丝虫ELISA试剂盒评估热处理前后天然被O. lupi感染的狗的血清样品的潜在交叉反应性。我们从自然感染了O. lupi的23只狗中获得了血清。这些狗患有眼病，并已协商安排因感染或摘除手术切除眼结节。按照制造商的协议进行前后热处理，使用DiroCHEK®Heartworm Antigen Test试剂盒（Synbiotics Corporation，Zoetis，Kalamazoo，MI，美国）对样品进行三次重复测试。使用干式加热块在103°C下对样品进行10分钟的热处理，然后在1818x g下离心20分钟。在总共23只狗中，有19只（82.6％）不论热处理如何都未检测到抗原，三只狗在热处理前后均呈阳性，而一只狗在热处理后变为阳性。这三只在热处理前后呈阳性的狗被负责这些情况的兽医确诊感染了Dirofilaria炎。而且我们无法获得病史或仅追踪在热处理后变成阳性的那只狗。我们的数据表明，在热处理之前或之后在犬血清中使用DiroCHEK®时，O。lupi感染不应导致假阳性。在DiroCHEK®中测试抗原呈阳性的临床眼盘尾丝虫病犬可能与D.线虫感染同时感染，应进一步测试，包括评估血液中的微丝aria和诊断性成像。如果确诊为心丝虫感染，则应按照美国心丝虫学会或其他当地组织的指南，将动物纳入推荐的治疗方案中。热处理之前或之后。在DiroCHEK®中测试抗原呈阳性的临床眼盘尾丝虫病犬可能与D.线虫感染共感染，应进一步测试，包括评估血液中的微丝aria和诊断性成像。如果确诊为心丝虫感染，则应按照美国心丝虫学会或其他当地组织的指南，将动物纳入推荐的治疗方案中。热处理之前或之后。在DiroCHEK®中测试抗原呈阳性的临床眼盘尾丝虫病犬可能与D.线虫感染同时感染，应进一步测试，包括评估血液中的微丝aria和诊断性成像。如果确诊为心丝虫感染，则应按照美国心丝虫学会或其他当地组织的指南，将动物纳入推荐的治疗方案中。