Bendas Alexandre José Rodrigues, Mendes-de-Almeida Flavya, Von Simson Cristiano, Labarthe Norma
Programa de Pós-Graduação em Medicina Veterinária, Faculdade de Veterinária Universidade Federal Fluminense, R. Vital Brazil Filho, 64, Santa Rosa, Niterói-RJ, 24230-340, Brazil.
Veterinary Services, Virbac US P.O. box 162059, Ft Worth, TX, 76161, USA.
Parasit Vectors. 2017 May 19;10(1):246. doi: 10.1186/s13071-017-2189-2.
Considering the recent information on the increase of Dirofilaria immitis antigen detection by rapid assays in canine blood samples after heat treatment, the proposal that immune complexes block D. immitis antigen detection and that macrocyclic lactone + doxycycline (alternative protocol) might lead to increased production of those immune complexes, resulting in the erroneous diagnosis of adult worm elimination, and that there is no recommended adulticide marketed in Brazil, a study was performed to evaluate the interference of moxidectin + doxycycline (moxi-doxy) on diagnostic procedures when heartworm positive dogs are treated with this alternative protocol. Twenty-two naturally infected pet dogs were treated monthly with topical 10% imidacloprid + 2.5% moxidectin and with oral doxycycline (10 mg/kg BID/30 days) (moxi-doxy). All the dogs had their microfilaremia level determined prior to the first day of treatment, and were tested every 6 months for microfilariae (Mf) detection prior to heating, and for antigen detection prior to and after heating, the sample.
The results indicate that the treatment protocol can eliminate adult heartworms as early as 6 months after the first dose, especially in low microfilaremic dogs (< 300 Mf/ml). In this study, all dogs were free of heartworm antigen after 18-24 months of treatment. In a comparison of pre-heated samples and non-heated samples, sample pre-heating increased antigen detection sensitivity, and non-heated samples tended to be antigen-negative earlier than the pre-heated samples, especially when dogs had low microfilaremia levels. These discrepancies were not present in a subsequent sample of the same dog 6 months later.
Two negative antigen test results 6 months apart can be recommended as the criterion to consider when a dog has been cleared of infection. The initial microfilaremia level of a dog can be used to estimate the necessary time frame to end the treatment period.
鉴于近期有信息表明，热处理后的犬类血液样本通过快速检测法检测伊氏锥虫抗原的结果有所增加，有人提出免疫复合物会阻碍伊氏锥虫抗原检测，大环内酯类药物 + 强力霉素（替代方案）可能会导致这些免疫复合物的产生增加，从而导致对成虫清除情况的错误诊断，且巴西市场上没有推荐的杀成虫剂，因此开展了一项研究，以评估莫昔克丁 + 强力霉素（莫昔 - 强力霉素）对感染犬心丝虫的犬只采用此替代方案治疗时诊断程序的干扰。22只自然感染的宠物犬每月接受外用10%吡虫啉 + 2.5%莫昔克丁以及口服强力霉素（10毫克/千克，每日两次，共30天）（莫昔 - 强力霉素）治疗。所有犬只在治疗首日之前测定其微丝蚴血症水平，并在加热前每6个月检测微丝蚴（Mf），在样本加热前后检测抗原。
结果表明，治疗方案最早在首剂治疗后6个月即可清除成虫心丝虫，尤其是微丝蚴血症水平较低（<300 Mf/ml）的犬只。在本研究中，所有犬只在治疗18 - 24个月后均未检测到心丝虫抗原。在预热样本与未预热样本的比较中，样本预热提高了抗原检测灵敏度，且未预热样本往往比预热样本更早呈抗原阴性，尤其是当犬只微丝蚴血症水平较低时。6个月后同一只犬的后续样本中不存在这些差异。
可以推荐以间隔6个月的两次阴性抗原检测结果作为判断犬只已清除感染的标准。犬只的初始微丝蚴血症水平可用于估计结束治疗期所需的时间范围。
