Dipartimento di Medicina Veterinaria, Università degli Studi di Bari, Valenzano, Italy.
Department of Veterinary Science, University of Parma, Parma, Italy.
Acta Trop. 2022 Aug;232:106513. doi: 10.1016/j.actatropica.2022.106513. Epub 2022 May 19.
Bacteria of the genus Wolbachia are endosymbionts of parasitic filarial nematodes, including Dirofilaria immitis, and are a target for the treatment of canine heartworm disease. In the present study, 53 naturally-infected dogs were divided in three groups, based on their positivity to D. immitis by antigen and Knott tests, to assess the efficacy of doxycycline treatment in eliminating Wolbachia from circulating blood. At T0, dogs that scored positive to both tests (G1) or to antigen only (G2) were submitted to doxycycline (10 mg/kg BID PO) treatment and to 10% Imidacloprid + 2.5% Moxidectin (Advocate®), while those negative to both tests (G3) received only 10% Imidacloprid + 2.5% Moxidectin (Advocate®). All dogs were followed-up for one year, monthly treated with Advocate® and regularly monitored by antigen and Knott tests. During the whole period, all blood samples were screened for Wolbachia-D. immitis DNA load by quantitative real-time PCR (qPCR). At T0, 88.2% of the microfilariemic dogs were positive for Wolbachia DNA, while none of the dogs from G2 or G3 were positive. Wolbachia DNA was no longer detectable in dogs from G1 following 1 month of doxycycline treatment and microfilariae (mfs) were cleared at T2. All dogs from the G1 and G2 were negative for D. immitis antigen at 12 months. Results of this study suggest that successful elimination of mfs by doxycycline is associated with complete clearance of Wolbachia DNA in D. immitis-naturally infected dogs.
属细菌沃尔巴克氏体是寄生性丝虫的内共生体，包括犬恶丝虫，是治疗犬心丝虫病的靶标。在本研究中，根据抗原和 Knott 试验对犬恶丝虫的阳性结果，将 53 只自然感染的犬分为三组，以评估强力霉素治疗消除循环血液中沃尔巴克氏体的疗效。在 T0 时，对两种试验均呈阳性（G1）或仅对抗原呈阳性（G2）的犬给予强力霉素（10mg/kg BID PO）治疗和 10%伊维菌素+2.5%莫昔克丁（Advocate®），而对两种试验均呈阴性的犬（G3）仅给予 10%伊维菌素+2.5%莫昔克丁（Advocate®）。所有犬均随访一年，每月用 Advocate®治疗，并定期进行抗原和 Knott 试验监测。在整个期间，所有血液样本均通过定量实时 PCR（qPCR）筛查沃尔巴克氏体-犬恶丝虫 DNA 载量。在 T0 时，88.2%的微丝蚴血症犬沃尔巴克氏体 DNA 呈阳性，而 G2 或 G3 组的犬均为阴性。在强力霉素治疗 1 个月后，G1 组犬的沃尔巴克氏体 DNA 不再可检测到，微丝蚴（mfs）在 T2 时被清除。G1 和 G2 组的所有犬在 12 个月时均对犬恶丝虫抗原呈阴性。本研究结果表明，强力霉素成功消除 mfs 与犬恶丝虫中沃尔巴克氏体 DNA 的完全清除有关。
