Özbakış G, Doğanay A
Department of Parasitology, Faculty of Veterinary Medicine, Ankara University, Ankara, Turkey.
J Helminthol. 2019 Aug 9;94:e70. doi: 10.1017/S0022149X19000609.
Toxocara canis is an important zoonotic roundworm distributed worldwide. The infective larvae of T. canis are one of the causes of visceral larva migrans (VLM), a clinical syndrome in humans. Diagnosing VLM is difficult, and the differential diagnosis of the larval development stage is limited. Therefore, this experimental research aimed to diagnose T. canis larvae using a molecular method, not only in liver tissue, which is the most commonly affected tissue, but also in the limb muscles, lungs and brain tissues. For this purpose, 24 BALB/c mice were infected with 1000 embryonated T. canis eggs. Necropsies were performed on the second, fourth, seventh and 14th days post-infection. While a part of the samples were digested with pepsin-HCl, the molecular method was used for the remainder of the samples to replicate the mitochondrial DNA adenosine triphosphate (ATP) synthase subunit-6 gene region of T. canis. BbsI, a restriction endonuclease, was used to determine the specificity of the amplicons obtained from Polymerase chain reaction (PCR). The detection limit for embryonated eggs was recorded. The PCR results showed that the sensitivity of the PCR analysis was 83.3% in the liver (with 88.8% accuracy), 87.5% in the lungs (with 91.6% accuracy) and 75.0% in the brain, forelimb and hindlimb muscles (with 83.3% accuracy). In all tissues, the test specificity was determined to be 100%. In this study, the molecular method was applied to only experimentally infected BALB/c mice tissues; thus, it is suggested that it can be also employed in different paratenic hosts and materials possibly infected with T. canis.
犬弓首蛔虫是一种重要的人畜共患蛔虫,分布于世界各地。犬弓首蛔虫的感染性幼虫是人类内脏幼虫移行症(VLM)的病因之一,VLM是一种人类临床综合征。诊断VLM很困难,幼虫发育阶段的鉴别诊断也很有限。因此,本实验研究旨在使用分子方法诊断犬弓首蛔虫幼虫,不仅要在最常受影响的肝脏组织中进行诊断,还要在肢体肌肉、肺和脑组织中进行诊断。为此,将24只BALB/c小鼠感染1000枚犬弓首蛔虫感染性虫卵。在感染后的第2、4、7和14天进行尸检。一部分样本用胃蛋白酶 - 盐酸消化,其余样本则采用分子方法扩增犬弓首蛔虫线粒体DNA三磷酸腺苷(ATP)合酶亚基6基因区域。使用限制性内切酶BbsI来确定聚合酶链反应(PCR)扩增产物的特异性。记录感染性虫卵的检测限。PCR结果显示,PCR分析在肝脏中的灵敏度为83.3%(准确率为88.8%),在肺中的灵敏度为87.5%(准确率为91.6%),在脑、前肢和后肢肌肉中的灵敏度为75.0%(准确率为83.3%)。在所有组织中,检测特异性均为100%。在本研究中,分子方法仅应用于实验感染的BALB/c小鼠组织;因此,建议该方法也可用于可能感染犬弓首蛔虫的不同转续宿主和材料。