Klun Ivana, Uzelac Aleksandra, Villena Isabelle, Mercier Aurélien, Bobić Branko, Nikolić Aleksandra, Rajnpreht Irena, Opsteegh Marieke, Aubert Dominique, Blaga Radu, van der Giessen Joke, Djurković-Djaković Olgica
National Reference Laboratory for Toxoplasmosis, Centre of Excellence for Food- and Vector-Borne Zoonoses, Institute for Medical Research, University of Belgrade, Dr Subotića 4, 11129, Belgrade, Serbia.
Centre National de Référence de la Toxoplasmose, Laboratoire de Parasitologie-Mycologie, CHU Maison Blanche, EA 3800 SFR CAP-SANTE, UFR Médecine Université de Reims Champagne-Ardenne, 45 rue Cognacq-Jay, 51092, Reims, France.
Parasit Vectors. 2017 Apr 4;10(1):167. doi: 10.1186/s13071-017-2104-x.
Consumption of undercooked or insufficiently cured meat is a major risk factor for human infection with Toxoplasma gondii. Although horsemeat is typically consumed rare or undercooked, information on the risk of T. gondii from infected horse meat to humans is scarce. Here, we present the results of a study to determine the presence of T. gondii infection in slaughter horses in Serbia, and to attempt to isolate viable parasites.
The study included horses from all regions of Serbia slaughtered at two abattoirs between June 2013 and June 2015. Blood sera were tested for the presence of specific IgG T. gondii antibodies by the modified agglutination test (MAT), and samples of trypsin-digested heart tissue were bioassayed in mice. Cyst-positive mouse brain homogenates were subjected to DNA extraction and T. gondii strains were genotyped using 15 microsatellite markers (MS).
A total of 105 slaughter horses were sampled. At the 1:6 cut-off 48.6% of the examined horses were seropositive, with the highest titre being 1:400. Viable parasites were isolated from two grade type mares; both parasite isolates (RS-Eq39 and RS-Eq40) were T. gondii type III, and both displayed an increased lethality for mice with successive passages. These are the first cases of isolation of T. gondii from horses in Serbia. When compared with a worldwide collection of 61 type III and type III-like strains, isolate RS-Eq39 showed a combination of MS lengths similar to a strain isolated from a duck in Iran, and isolate RS-Eq40 was identical in all markers to three strains isolated from a goat from Gabon, a sheep from France and a pig from Portugal. Interestingly, the source horses were one seronegative and one weakly seropositive.
The isolation of viable T. gondii parasites from slaughter horses points to horsemeat as a potential source of human infection, but the fact that viable parasites were isolated from horses with only a serological trace of T. gondii infection presents further evidence that serology may not be adequate to assess the risk of toxoplasmosis from horsemeat consumption. Presence of T. gondii type III in Serbia sheds more light into the potential origin of this archetypal lineage in Europe.
食用未煮熟或未充分腌制的肉类是人类感染刚地弓形虫的主要风险因素。尽管马肉通常以半熟或未煮熟的状态食用，但关于受感染马肉对人类造成刚地弓形虫感染风险的信息却很匮乏。在此，我们展示一项研究的结果，该研究旨在确定塞尔维亚屠宰马中刚地弓形虫感染的存在情况，并尝试分离出活的寄生虫。
该研究纳入了2013年6月至2015年6月期间在两个屠宰场屠宰的来自塞尔维亚所有地区的马。通过改良凝集试验（MAT）检测血清中是否存在特异性抗刚地弓形虫IgG抗体，并将胰蛋白酶消化的心脏组织样本在小鼠中进行生物测定。对囊肿阳性的小鼠脑匀浆进行DNA提取，并使用15个微卫星标记（MS）对刚地弓形虫菌株进行基因分型。
总共采集了105匹屠宰马的样本。在1:6的截断值下，48.6%的被检测马血清呈阳性，最高滴度为1:400。从两匹母马中分离出了活的寄生虫；两个寄生虫分离株（RS-Eq39和RS-Eq40）均为刚地弓形虫III型，并且在连续传代后对小鼠均表现出更高的致死率。这是塞尔维亚首次从马中分离出刚地弓形虫的案例。与全球收集的61个III型和III型样菌株相比，分离株RS-Eq39显示出的微卫星长度组合与从伊朗一只鸭子中分离出的菌株相似，分离株RS-Eq40在所有标记上与从加蓬一只山羊、法国一只绵羊和葡萄牙一头猪中分离出的三个菌株相同。有趣的是，源马一匹血清阴性，一匹血清弱阳性。
从屠宰马中分离出活的刚地弓形虫寄生虫表明马肉是人类感染的潜在来源，但从仅具有刚地弓形虫感染血清学痕迹的马中分离出活的寄生虫这一事实进一步证明，血清学可能不足以评估食用马肉导致弓形虫病的风险。塞尔维亚存在刚地弓形虫III型为该原型谱系在欧洲的潜在起源提供了更多线索。
