Atterby H, Learmount J, Conyers C, Zimmer I, Boonham N, Taylor M
Central Science Laboratory, Sand Hutton, York YO41 1LZ, UK.
Vet Parasitol. 2009 Apr 6;161(1-2):92-8. doi: 10.1016/j.vetpar.2008.12.009. Epub 2008 Dec 13.
Trichinellosis is a widespread zoonotic disease caused by nematodes of the genus Trichinella. Most human infections are caused by Trichinella spiralis, with pig meat being the main source of infection. As a consequence, all countries in the EU inspect slaughtered animals to prevent the distribution of infected meat to consumers. However, Trichinella spp. infect nearly all orders of mammals and so wildlife monitoring is often required in regions that want to provide evidence of negligible risk of infection in pigs. Surveys of the parasite in the Red fox are generally accepted as evidence of the wildlife reservoir. The EU reference method of detection in food animals for human consumption involves digestion of the host muscle followed by microscopic screening of the resultant sediment for trichinae and the method has been adapted for use with foxes. This work describes the development of a real-time PCR assay for the detection of Trichinella in fox tissue. The assay was designed to the Internal Transcribed Spacer 2 region of the Trichinella genome. Initial assay development was carried out using infected mouse tissue, as positive foxes have not been reported in the UK since 1957. The developed assay, which was shown to be specific for T. spiralis, was then tested using fox muscle spiked with isolated larvae at the rate of 1 larva per gram (LPG) of muscle tissue, as this is the theoretical detection limit using the digest method, as well as 0.5 and 0.1 LPG. The PCR assay was shown to detect the larvae at the higher infection rates and, by testing dilutions of the extracted DNA, it was demonstrated that a potential limit of detection of approx. 0.01 larvae per gram of tissue homogenate may be possible.
旋毛虫病是一种由旋毛虫属线虫引起的广泛传播的人畜共患病。大多数人类感染是由旋毛虫引起的，猪肉是主要感染源。因此，欧盟所有国家都对屠宰动物进行检查，以防止受感染的肉类流向消费者。然而，旋毛虫属感染几乎所有哺乳动物目，因此在希望提供猪感染风险可忽略不计证据的地区，通常需要进行野生动物监测。对赤狐体内寄生虫的调查通常被视为野生动物宿主的证据。欧盟用于检测供人类食用的食用动物的参考方法包括消化宿主肌肉，然后在显微镜下筛选所得沉淀物中的旋毛虫，该方法已适用于狐狸。这项工作描述了一种用于检测狐狸组织中旋毛虫的实时PCR检测方法的开发。该检测方法针对旋毛虫基因组的内转录间隔区2区域设计。最初的检测方法开发是使用受感染的小鼠组织进行的，因为自1957年以来英国尚未报告过阳性狐狸。然后使用以每克肌肉组织1条幼虫（LPG）的比例添加分离幼虫的狐狸肌肉对开发的检测方法进行测试，因为这是使用消化法的理论检测限，同时还测试了0.5和0.1 LPG。PCR检测方法显示能够检测到较高感染率的幼虫，并且通过测试提取DNA的稀释液，证明每克组织匀浆的潜在检测限可能约为0.01条幼虫。
