Idris Sanaa M, Elmagzoub Wisal A, Okuni Julius B, Ojok Lonzy, Mukhtar Mohamed E, Abdalla Enass M, El Sanousi Sulieman M, Amanzada Ahmad, Truyen Uwe, El Wahed Ahmed Abd, Eltayeb ElSagad, Eltom Kamal H, Gameel Ahmed A
Department of Animal Health and Safety of Animal Products, Institute for Studies and Promotion of Animal Exports, University of Khartoum, Khartoum North, 13314 Shambat, Sudan.
Department of Pathology, Faculty of Veterinary Medicine, University of Khartoum, Khartoum North, 13314 Shambat, Sudan.
BMC Vet Res. 2025 Jul 29;21(1):496. doi: 10.1186/s12917-025-04920-8.
Paratuberculosis (PTB), caused by Mycobacterium avium subsp. paratuberculosis (MAP), is a contagious and chronic enteric disease of ruminants and many non-ruminants leading to emaciation and death of the animal. PTB is poorly investigated in sheep and goats in Sudan, where these animals contribute significantly to food security and poverty alleviation as sources of income. They also play an important role in the national economy through animal exports. The objectives of this study were to investigate the prevalence of PTB and associated risk factors in small ruminants. Blood and faecal samples were collected from 818 sheep and goats aged > 1 year in 111 flocks distributed over five states (Blue Nile, West Kordofan, Khartoum, the Gezira and White Nile) of the country from November 2020 to October 2022. Serum samples were tested by an enzyme-linked immunosorbent assay (ELISA) for detection of MAP antibodies and the faecal samples were tested for MAP DNA using a recombinase aided amplification (RAA) assay.
The overall true animal-level prevalence of PTB was 10.7% by RAA (4.2% in sheep, 6.5% in goats) and 1.7% by ELISA (0.7% in sheep, 1.0% in goats). At the flock level, prevalence was 41.8% by RAA and 8.5% by ELISA. While no significant associations were found between animal-level factors and PTB, several flock-level factors including breed homogeneity, source of new animals, management system, animal movement, separation of sick animals, and flock history of PTB were significantly associated with MAP detection (P < 0.05).
The high flock-level prevalence of MAP DNA indicates a potential risk for environmental dissemination, especially under open grazing systems. Despite the relatively low seroprevalence, molecular detection suggests subclinical infection may be underdiagnosed. These findings highlight the importance of using combined diagnostic methods for effective PTB surveillance and control. Improved flock management practices are recommended to reduce MAP transmission and environmental contamination.
副结核病（PTB）由鸟分枝杆菌副结核亚种（MAP）引起，是反刍动物和许多非反刍动物的一种传染性慢性肠道疾病，可导致动物消瘦和死亡。在苏丹，绵羊和山羊的副结核病研究较少，而这些动物作为收入来源，对粮食安全和减贫做出了重大贡献。它们还通过动物出口在国民经济中发挥重要作用。本研究的目的是调查小型反刍动物中副结核病的流行情况及相关风险因素。2020年11月至2022年10月，从该国五个州（青尼罗州、西科尔多凡州、喀土穆州、杰济拉州和白尼罗州）分布的111个羊群中，采集了818只年龄大于1岁的绵羊和山羊的血液和粪便样本。血清样本通过酶联免疫吸附测定（ELISA）检测MAP抗体，粪便样本使用重组酶辅助扩增（RAA）测定法检测MAP DNA。
通过RAA法检测，副结核病的总体真实动物水平患病率为10.7%（绵羊为4.2%，山羊为6.5%），通过ELISA法检测为1.7%（绵羊为0.7%，山羊为1.0%）。在羊群水平上，RAA法检测的患病率为41.8%，ELISA法检测为8.5%。虽然在动物水平因素与副结核病之间未发现显著关联，但包括品种同质性、新动物来源、管理制度、动物流动、病畜隔离以及羊群副结核病病史在内的几个羊群水平因素与MAP检测显著相关（P<0.05）。
MAP DNA在羊群水平上的高患病率表明存在环境传播的潜在风险，尤其是在开放式放牧系统下。尽管血清阳性率相对较低，但分子检测表明亚临床感染可能未得到充分诊断。这些发现凸显了使用联合诊断方法进行有效副结核病监测和控制的重要性。建议改进羊群管理措施以减少MAP传播和环境污染。
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