The Mycobacterium tuberculosis complex (MTBC) species includes both M. tuberculosis, the primary cause of human tuberculosis (TB), and M. bovis, the primary cause of bovine tuberculosis (bTB), as well as other closely related Mycobacterium species. Zoonotic transmission of M. bovis from cattle to humans was recognized more than a century ago, but transmission of MTBC species from humans to cattle is less often recognized. Within the last decade, multiple published reports from around the world describe human-to-cattle transmission of MTBC. Three probable cases of human-to-cattle MTBC transmission have occurred in the United States since 2013. In the first case, detection of active TB disease (M. bovis) in a dairy employee in North Dakota prompted testing and ultimate detection of bTB infection in the dairy herd. Whole genome sequencing (WGS) demonstrated a match between the bTB strain in the employee and an infected cow. North Dakota animal and public health officials concluded that the employee’s infection was the most likely source of disease introduction in the dairy. The second case involved a Wisconsin dairy herd with an employee diagnosed with TB disease in 2015. Subsequently, the herd was tested twice with no disease detected. Three years later, a cow originating from this herd was detected with bTB at slaughter. The strain in the slaughter case matched that of the past employee based on WGS. The third case was a 4-month-old heifer calf born in New Mexico and transported to Texas. The calf was TB tested per Texas entry requirements and found to have M. tuberculosis. Humans are the suspected source of M. tuberculosis in cattle; however, public health authorities were not able to identify an infected human associated with the cattle operation. These 3 cases provide strong evidence of human-to-cattle transmission of MTBC organisms and highlight human infection as a potential source of introduction of MTBC into dairy herds in the United States. To better understand and address the issue, a multisectoral One Health approach is needed, where industry, public health, and animal health work together to better understand the epidemiology and identify preventive measures to protect human and animal health.

中文翻译：

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美国的人对牛结核分枝杆菌复合群传播

结核分枝杆菌复合群 (MTBC) 物种包括人类结核病 (TB) 的主要原因结核分枝杆菌和牛结核分枝杆菌 (bTB) 的主要原因，以及其他密切相关的分枝杆菌物种。牛分枝杆菌从牛到人类的人畜共患病传播早在一个多世纪前就已被认识到，但 MTBC 物种从人类传播到牛的情况却鲜为人知。在过去十年中，来自世界各地的多份已发表报告描述了 MTBC 的人与牛传播。自 2013 年以来，美国发生了三起人与牛 MTBC 传播的可能病例。 在第一起病例中，北达科他州一名奶业员工检测到活动性结核病（牛分枝杆菌）促使检测并最终检测出 bTB 感染在奶牛群中。全基因组测序 (WGS) 证明员工的 bTB 菌株与受感染的奶牛匹配。北达科他州的动物和公共卫生官员得出结论，该员工的感染是乳制品中最有可能的疾病传播源。第二个案例涉及威斯康星州的一个奶牛群，其中一名员工在 2015 年被诊断出患有结核病。随后，对该牛群进行了两次检测，均未发现疾病。三年后，一头来自该牛群的母牛在屠宰时检测到 bTB。根据WGS，屠宰案件中的应变与过去雇员的应变相匹配。第三个病例是一只出生在新墨西哥州并被运送到德克萨斯州的 4 个月大的小母牛犊。小牛按照德克萨斯州的入学要求进行了结核病检测，发现患有结核分枝杆菌。人类是牛中结核分枝杆菌的可疑来源；然而，公共卫生当局无法确定与养牛场有关的感染者。这 3 个案例提供了 MTBC 生物体在人与牛之间传播的有力证据，并强调了人类感染是将 MTBC 引入美国奶牛群的潜在来源。为了更好地理解和解决这个问题，需要一种多部门的“同一个健康”方法，行业、公共卫生和动物卫生部门共同努力，以更好地了解流行病学并确定保护人类和动物健康的预防措施。这 3 个案例提供了 MTBC 生物体在人与牛之间传播的有力证据，并强调了人类感染是将 MTBC 引入美国奶牛群的潜在来源。为了更好地理解和解决这个问题，需要一种多部门的“同一个健康”方法，行业、公共卫生和动物卫生部门共同努力，以更好地了解流行病学并确定保护人类和动物健康的预防措施。这 3 个案例提供了 MTBC 生物体在人与牛之间传播的有力证据，并强调了人类感染是将 MTBC 引入美国奶牛群的潜在来源。为了更好地理解和解决这个问题，需要一种多部门的“同一个健康”方法，行业、公共卫生和动物卫生部门共同努力，以更好地了解流行病学并确定保护人类和动物健康的预防措施。