Department of Pathology and Parasitology, University of Veterinary and Pharmaceutical Sciences, Palackého 1-3, 612 42 Brno, Czech Republic.
Food Microbiol. 2014 Apr;38:167-70. doi: 10.1016/j.fm.2013.08.011. Epub 2013 Aug 31.
Pigs represent an important source of food in many countries, and undercooked pork containing tissue cysts is one of the most common sources of Toxoplasma gondii infection for humans. A magnetic capture method for the isolation of T. gondii DNA and quantitative real-time PCR targeting the 529 bp TOXO repeat element were used to estimate the parasite burden in different tissues of pigs experimentally infected with T. gondii oocysts, and to determine the predilection sites of T. gondii in this host species. The highest concentration of T. gondii DNA was found in brain tissues, equivalent to [median] 553.7 (range 3857.7-121.9) parasites per gram, followed by lungs, heart and dorsal muscles with median values corresponding to 0.3 (range 61.3-0.02); 2.6 (range 7.34-0.37) and 0.6 (range 2.81-0.31) parasites per gram of tissue, respectively. Skeletal muscles from fore and hindlimb, liver and kidney presented very low infection burdens equivalent to [median] ≤0.2 parasites per gram of tissues, and no parasite DNA could be detected in the spleen. This study contributes to understanding the value of different pig tissues as a source of T. gondii infection for humans and shows that the brain, while not being of major importance as human food source, may represent a first-line selection tissue when performing non-serological surveys (e.g. bioassays, histopathological, immunohistochemical or molecular studies) to detect T. gondii infections in pigs.
猪在许多国家是重要的食物来源，未煮熟的含有组织包囊的猪肉是人类感染刚地弓形虫最常见的途径之一。本研究采用磁珠捕获法分离刚地弓形虫 DNA 和针对 529bp TOXO 重复元件的实时定量 PCR 方法，估计了实验感染弓形虫卵囊的猪不同组织中的寄生虫负荷，并确定了该宿主物种中弓形虫的倾向部位。刚地弓形虫 DNA 浓度最高的组织是脑组织，相当于每克组织中有 [中位数]553.7（范围 3857.7-121.9）个寄生虫，其次是肺、心脏和背肌，中位数分别对应 0.3（范围 61.3-0.02）；2.6（范围 7.34-0.37）和 0.6（范围 2.81-0.31）个寄生虫/克组织。前肢和后肢的骨骼肌、肝脏和肾脏的感染负担非常低，相当于 [中位数]≤0.2 个寄生虫/克组织，脾脏中无法检测到寄生虫 DNA。本研究有助于了解不同猪组织作为人类弓形虫感染源的价值，并表明大脑虽然不是人类食物的主要来源，但在进行非血清学调查（例如生物测定、组织病理学、免疫组织化学或分子研究）以检测猪弓形虫感染时，可能代表首选组织。
