Tools to mitigate disease associated with Streptococcus zooepidemicus: an emerging threat to the Canadian pork industry

自2019年春季以来，加拿大和美国报告了多起母猪死亡(50%，猝死，呼吸症状轻微)和流产(比正常情况高出11倍)的病例。这些病例被明确地与马链球菌动物流行亚种(S.zoo)联系在一起，它现在被认为是对北美猪肉行业的新威胁。我们的团队对加拿大的第一批病例做出了反应，确定了细菌的特征，并通过诊断测试的开发为兽医和行业提供支持。使用标准自体疫苗的初步现场试验并未产生预防感染的效果。因此，目前在受影响农场控制疾病的工具仅限于减少人口，在更大的生产系统中估计要花费超过1500万加元。展望未来，为了防止加拿大各地的进一步损失，开发有效的预防和控制方法是至关重要的。这里提出的工作目标是调查预防和控制S.zoo的工具的开发，以降低猪的疾病严重程度，并潜在地预防感染。我们将使用尖端研究工具(例如转录学)来描述S.zoo感染猪的方式和地点，并利用这一知识开发疫苗或非抗生素化合物，以保护猪免受感染并减少死亡。

Since spring 2019, multiple cases of sow mortality (>50%, sudden death with minimal respiratory signs) and abortions (11 times higher than normal) have been reported in Canada and the USA. These cases were definitively associated with Streptococcus equi subspecies zooepidemicus (S. zoo), which is now considered an emerging threat to the North American pork industry. Our team responded to the first cases in Canada, characterizing the bacteria and supporting veterinarians and the industry with the development of diagnostic tests. Preliminary field trials using standard autogenous vaccines did not result in protection against infection. Thus, current tools to control the disease in affected farms are limited to depopulation, which is estimated to cost over CAD $15 million in larger production systems. Moving forward, to prevent further losses across Canada, the development of efficient preventive and control methods is critical.The goal of the work proposed here is to investigate the development of tools for the prevention and control of S. zoo, to reduce disease severity in pigs and potentially prevent infection. We will employ cutting edge research tools (e.g. transcriptomics) to characterize how and where S. zoo infects pigs, and employ this knowledge to develop a vaccine or non-antibiotic compounds that will protect pigs from infection and reduce deaths.