Department of Parasitology and Parasitic Diseases, Faculty of Veterinary Medicine, University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca, 3-5 Calea Mănăştur Street, 400372, Cluj-Napoca, Cluj-Napoca, Romania.
Department of Genetics and Hereditary Diseases, Faculty of Veterinary Medicine, University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca, 3-5 Calea Mănăştur Street, 400372, Cluj-Napoca, Cluj-Napoca, Romania.
Parasit Vectors. 2023 Jan 23;16(1):24. doi: 10.1186/s13071-022-05634-8.
Toxoplasmosis is a widespread zoonosis caused by the intracellular protozoan parasite Toxoplasma gondii. Limited epidemiological information is available about the prevalence of T. gondii in sheep in Romania, and a high incidence would have implications for both the economy and public health. To our knowledge, no studies are available about the T. gondii strains circulating in lambs. The objective of this study was to assess the prevalence of T. gondii in sheep (serology), lambs (serology, bioassay, PCR) and sheep abortions (PCR) in Romania. Moreover, the study aimed to perform the genetic characterization of T. gondii isolates from lambs.
Serum samples collected from 2650 sheep (2067 adults and 583 lambs) were tested for anti-T. gondii antibodies (IgG) using a commercial ELISA kit. Likewise, 328 pairs of diaphragmatic muscle-serum samples were collected from lambs aged between 2 and 4 months. Lamb serum samples were analyzed using MAT for anti-T. gondii antibody detection. The diaphragm tissue samples from MAT-positive lambs (at a dilution ≥ 1:25) were bioassayed in mice. The T. gondii strains were genotyped using 15 microsatellites markers. Additionally, brain and heart samples from 76 sheep abortions were analyzed for T. gondii DNA by polymerase chain reaction (PCR) targeting the 529-bp repeat region (REP529).
The results showed that more than half of the tested sheep were T. gondii seropositive (53.5%). The seroprevalence was significantly higher in adults (61.1%) than in lambs (26.4%). The seroprevalence of T. gondii infection in slaughtered lambs, by MAT, was 37.5% (123/328). There were bioassayed in mice 56 diaphragmatic tissues from 123 seropositive lambs. Toxoplasma gondii strains were isolated from 18 (32.1%) lambs intended for human consumption. All T. gondii strains were confirmed by PCR. Six strains were genotyped using 15 microsatellite markers and belonged to genotype II. Toxoplasma gondii DNA was detected in 11.8% (9/76) of sheep abortions.
The present study showed the presence of T. gondii in sheep in all the regions considered in the study. The high prevalence of T. gondii infection in sheep and lambs, demonstrated by serology, molecular analysis and bioassay, highlighted that there is an important risk of human infection in consuming raw or undercooked sheep/lamb meat.
弓形虫病是一种由细胞内原生动物寄生虫弓形虫引起的广泛人畜共患病。罗马尼亚关于绵羊中弓形虫的流行率的流行病学信息有限，而高发病率将对经济和公共卫生都产生影响。据我们所知，目前尚无关于绵羊中循环的弓形虫株的研究。本研究的目的是评估罗马尼亚绵羊（血清学）、羔羊（血清学、生物测定、PCR）和绵羊流产（PCR）中弓形虫的流行率。此外，本研究旨在对来自羔羊的弓形虫分离株进行遗传特征分析。
采集了 2650 只绵羊（2067 只成年羊和 583 只羔羊）的血清样本，使用商业 ELISA 试剂盒检测抗弓形虫抗体（IgG）。同样，采集了 328 对 2 至 4 月龄羔羊的膈肌-血清样本。使用 MAT 分析羔羊血清样本以检测抗弓形虫抗体。对 MAT 阳性（稀释度≥1:25）的羔羊膈肌组织样本进行生物测定。使用 15 个微卫星标记物对弓形虫株进行基因分型。此外，对 76 份绵羊流产的脑组织和心脏样本进行了针对 529 个重复区（REP529）的聚合酶链反应（PCR）分析，以检测弓形虫 DNA。
结果表明，超过一半的检测绵羊呈弓形虫血清阳性（53.5%）。成年羊的血清阳性率（61.1%）明显高于羔羊（26.4%）。MAT 检测屠宰羔羊的弓形虫感染血清阳性率为 37.5%（123/328）。从 123 份血清阳性的羔羊中，生物测定了 56 个膈肌组织。从用于人类消费的 18 只（32.1%）羔羊中分离出了弓形虫株。所有的弓形虫株均通过 PCR 得到确认。使用 15 个微卫星标记物对 6 株弓形虫株进行了基因分型，它们属于基因型 II。在 76 份绵羊流产中，11.8%（9/76）检测到了弓形虫 DNA。
本研究表明，在所研究的所有地区都存在绵羊中的弓形虫。血清学、分子分析和生物测定表明，绵羊和羔羊的弓形虫感染率很高，这表明食用生的或未煮熟的羊肉/羊肉存在感染人类的重要风险。
