Faculty of Animal Science and Technology, Yunnan Agricultural University, Kunming, Yunnan Province, 650201, PR China.
State Key Laboratory of Conservation and Utilization of Bio-Resources in Yunnan, Center for Life Science, School of Life Sciences, Yunnan University, Kunming, Yunnan Province, 650500, PR China.
Acta Parasitol. 2024 Sep;69(3):1592-1599. doi: 10.1007/s11686-024-00875-2. Epub 2024 Aug 20.
Toxoplasma gondii, a globally distributed zoonotic obligate intracellular parasite, infects a wide array of mammals, including humans, sheep, and birds. As a unique sheep breed in southwestern China, Yunnan semi-fine wool sheep occupies an important position in animal husbandry in Zhaotong due to its strong adaptability, high reproductive rate, and excellent wool quality. Lambs infected with T. gondii are prone to neurological symptoms and growth retardation, while T. gondii infection in ewes can cause abortions, stillbirths, and deformities, thus affecting sheep reproduction and sheep product quality. Meanwhile, mutton and dairy products contaminated with T. gondii can become potential sources of human infection, potentially threatening public health and safety.
To understand the T. gondii infection in semi-fine wool sheep in Zhaotong, Yunnan Province, 586 blood samples were collected and subjected to indirect hemagglutination assay (IHA) for T. gondii antibodies, and the infection-related factors were analyzed through cross-sectional analysis. In the meantime, nested PCR was conducted on a total of 217 samples collected from 31 rodents caught in and around the sheep breeding ground to test the T. gondii B1 gene in rodent tissues.
A total of 94 sera tested positive for T. gondii antibodies, with a total positive rate of 16.04% (94/586) (95% CI: 14.77-20.89). Cross-sectional statistical analysis on factors related to semi-fine wool sheep infection rate, including sampling season, sex, age, and weight, suggested that age (< 6 months: 23.81%; 6-12 months: 11.74%; > 12 months: 15.83%) was a significant factor explaining the infection rate differences (P = 0.003 < 0.05, χ = 11.62, df = 2). Thus, age was considered a key risk factor for T. gondii infection in this study (odds ratio, OR = 2.35, 95% CI: 1.42-3.87). Nested PCR analysis on 217 (heart, liver, spleen, lung, kidney, brain, and muscle) tissues from the 31 rodents indicated that 11 tested positive. The total infection rate of rodents in and around the breeding ground was 35.48% (11/31), and 14 samples tested positive, with a positive infection rate of 6.45% (14/217).
The T. gondii infection rates of semi-fine wool sheep and rodents from their breeding environment in Zhaotong, Yunnan Province, were high, necessitating enhanced prevention, control, and treatment measures to ensure the healthy breeding of semi-fine wool sheep and veterinary public health and safety.
刚地弓形虫是一种广泛分布的全球性动物专性细胞内寄生虫，感染范围广泛，包括人类、绵羊和鸟类等多种哺乳动物。作为中国西南地区特有的绵羊品种，云南半细毛羊因其适应性强、繁殖率高、羊毛品质优良，在昭通畜牧业中占有重要地位。感染刚地弓形虫的羔羊易出现神经症状和生长迟缓，而感染弓形虫的母羊则可导致流产、死产和畸形，从而影响绵羊繁殖和绵羊产品质量。同时，感染刚地弓形虫的羊肉和奶制品可能成为人类感染的潜在来源，对公共卫生和安全构成威胁。
为了解云南昭通半细毛羊刚地弓形虫的感染情况，采集了 586 份血液样本，采用间接血凝试验（IHA）检测 T. gondii 抗体，并通过横断面分析对感染相关因素进行分析。同时，对在绵羊养殖区及其周围捕获的 31 只啮齿动物的 217 个组织样本进行巢式 PCR，以检测啮齿动物组织中的 T. gondii B1 基因。
共有 94 份血清检测出 T. gondii 抗体阳性，总阳性率为 16.04%（94/586）（95%CI：14.77-20.89）。对半细毛羊感染率相关因素（采样季节、性别、年龄和体重）的横断面统计分析表明，年龄（<6 个月：23.81%；6-12 个月：11.74%；>12 个月：15.83%）是解释感染率差异的显著因素（P=0.003<0.05，χ²=11.62，df=2）。因此，年龄被认为是本研究中刚地弓形虫感染的关键危险因素（优势比，OR=2.35，95%CI：1.42-3.87）。对 31 只啮齿动物的 217 个（心、肝、脾、肺、肾、脑和肌肉）组织进行巢式 PCR 分析，结果有 11 个呈阳性。养殖区及其周围啮齿动物的总感染率为 35.48%（11/31），有 14 个样本呈阳性，阳性感染率为 6.45%（14/217）。
云南昭通半细毛羊及其养殖环境中的啮齿动物刚地弓形虫感染率较高，需要加强预防、控制和治疗措施，以确保半细毛羊的健康养殖和兽医公共卫生安全。
