Dámek Filip, Basso Walter, Joeres Maike, Thoumire Sandra, Swart Arno, Silva Anaëlle da, Gassama Inés, Škorič Miša, Smola Jiří, Schares Gereon, Blaga Radu, Koudela Břetislav
Anses, INRAE, Ecole Nationale Vétérinaire d'Alfort, Laboratoire de Santé Animale, BIPAR, 22 rue Pierre et Marie Curie, Maisons-Alfort Cedex 94701, France.
Institute of Parasitology, Vetsuisse-Faculty, University of Bern, Länggassstrasse 122, Bern CH-3012, Switzerland.
Vet Parasitol. 2024 Aug;330:110222. doi: 10.1016/j.vetpar.2024.110222. Epub 2024 Jun 5.
Toxoplasma gondii is a food-borne zoonotic parasite widespread in a variety of hosts, including humans. With a majority of infections in Europe estimated to be meat-borne, pork, as one of the most consumed meats worldwide, represents a potential risk for consumers. Therefore, we aimed to investigate the progress of T. gondii infection and tissue tropism in experimentally infected pigs, using different T. gondii isolates and infectious stages, i.e. tissue cysts or oocysts. Twenty-four pigs were allocated to treatment in four groups of six, with each group inoculated orally with an estimated low dose of either 400 oocysts or 10 tissue cysts of two European T. gondii isolates, a type II and a type III isolate. The majority of pigs seroconverted two weeks post-inoculation. Pigs infected with the type III isolate had significantly higher levels of anti-T. gondii antibodies compared to those infected with the type II isolate. Histopathological exams revealed reactive hyperplasia of the lymphatic tissue of all pigs. Additionally, a selected set of nine tissues was collected during necropsy at 50 dpi from each of the remaining 22 pigs for T. gondii DNA detection by quantitative real-time PCR. A positive result was obtained in 29.8 % (59/139) of tested tissues. The brain was identified as the most frequently positive tissue in 63.6 % (14/22) of the animals. In contrast, liver samples tested negative in all animals. The highest mean parasite load, calculated by interpolating the average Cq values on the standard curve made of ten-fold serial dilutions of the genomic DNA, corresponding to 10 to 10 tachyzoites/µL, was observed in shoulder musculature with an estimated concentration of 84.4 [0.0-442.5] parasites per gram of tissue. The study highlights the variability in clinical signs and tissue distribution of T. gondii in pigs based on the combination of parasite stages and strains, with type III isolates, particularly oocysts, causing a stronger antibody response and higher tissue parasite burden. These findings suggest the need for further investigation of type III isolates to better understand their potential risks to humans.
刚地弓形虫是一种食源性人畜共患寄生虫，广泛存在于包括人类在内的多种宿主中。据估计，欧洲的大多数感染是通过肉类传播的，猪肉作为全球消费最多的肉类之一，对消费者构成潜在风险。因此，我们旨在使用不同的刚地弓形虫分离株和感染阶段，即组织包囊或卵囊，研究实验感染猪中刚地弓形虫的感染进程和组织嗜性。将24头猪分为四组，每组6头进行处理，每组口服接种估计低剂量的两种欧洲刚地弓形虫分离株（II型和III型分离株）的400个卵囊或10个组织包囊。大多数猪在接种后两周血清阳转。与感染II型分离株的猪相比，感染III型分离株的猪的抗刚地弓形虫抗体水平显著更高。组织病理学检查显示所有猪的淋巴组织均有反应性增生。此外，在尸检时于感染后50天从其余22头猪的每头猪中收集一组选定的9种组织，通过定量实时PCR检测刚地弓形虫DNA。在29.8%（59/139）的测试组织中获得阳性结果。在63.6%（14/22）的动物中，大脑被确定为最常呈阳性的组织。相比之下，所有动物的肝脏样本检测均为阴性。通过在由基因组DNA十倍系列稀释制成的标准曲线上内插平均Cq值计算得出的最高平均寄生虫载量，对应于10至10速殖子/微升，在肩部肌肉组织中观察到，估计浓度为每克组织84.4 [0.0 - 442.5]个寄生虫。该研究强调了基于寄生虫阶段和菌株组合的猪中刚地弓形虫临床症状和组织分布的变异性，III型分离株，特别是卵囊，会引起更强的抗体反应和更高的组织寄生虫负担。这些发现表明需要进一步研究III型分离株，以更好地了解它们对人类的潜在风险。
