University Veterinary Teaching Hospital, Sydney, University of Sydney, Sydney, New South Wales, 2006, Australia.
Sydney School of Veterinary Science, Faculty of Science, University of Sydney, Sydney, New South Wales, 2006, Australia.
Aust Vet J. 2021 Aug;99(8):359-362. doi: 10.1111/avj.13074. Epub 2021 Apr 26.
Locally acquired canine heartworm (Dirofilaria immitis) infection in the temperate southern climate zones of Australia is currently rare. We report a case of locally acquired canine heartworm from Sydney, New South Wales in a 12-year-old Fox Terrier × Jack Russell female that presented with coughing and breathing difficulties. Absence of heartworm prevention and no travel outside Sydney was noted. Blood sample was D. immitis positive using antigen test, but negative on Modified Knott's testing. PCR confirmed the presence of D. immitis DNA in circulating blood. Echocardiographic examination revealed multiple parallel echogenic lines separated by a hypoechoic region ('tram-tracks') in the right pulmonary artery. The patient was treated and clinical condition gradually improved over the following 12 months. Antigen test remained positive for D. immitis at ~7 months and became negative at ~15 months after the start of the treatment. The most plausible scenario is importation of infected mosquito(s) in the luggage arriving from Queensland, Australia, common holiday destination for many Sydney-siders. We consider this a case of 'baggage canine heartworm'. Canine heartworm in dogs who did not travel should be considered in the differential diagnosis and D. immitis antigen test coupled with Modified Knott's test or PCR must be considered.
在澳大利亚温带南部气候带，本地获得性犬心丝虫（Dirofilaria immitis）感染目前较为罕见。我们报告了一例来自新南威尔士州悉尼的本地获得性犬心丝虫病例，病犬为一只 12 岁的狐梗×杰克罗素梗母犬，表现为咳嗽和呼吸困难。该犬未进行心丝虫预防，也未离开过悉尼。采用抗原检测发现该犬血液样本呈犬心丝虫阳性，但改良 Knott's 检测呈阴性。PCR 确认了循环血液中存在犬心丝虫 DNA。超声心动图检查显示右肺动脉内有多个平行的强回声线，其间有一低回声区（“轨道征”）。该犬接受了治疗，临床状况在接下来的 12 个月中逐渐改善。治疗开始约 7 个月后，犬心丝虫抗原检测仍呈阳性，约 15 个月后转为阴性。最有可能的情况是，从昆士兰州（澳大利亚许多悉尼居民的度假胜地）抵达的行李中携带了感染的蚊子。我们认为这是一例“行李犬心丝虫”。对于未旅行的犬，应考虑心丝虫感染的鉴别诊断，并且必须考虑犬心丝虫抗原检测结合改良 Knott's 检测或 PCR。
