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例母猪死亡（50%，伴有轻微呼吸体征的猝死）和流产（比正常情况高11倍）。这些病例明确与马链球菌亚种动物流行病（S. zoo）有关，该亚种现在被认为是对北美猪肉工业的新威胁。我们的团队对加拿大的第一批病例做出了反应，鉴定了细菌的特征，并支持兽医和行业开发诊断测试。使用标准自体疫苗的初步田间试验没有产生预防感染的效果。因此，目前在受影响的农场控制疾病的工具仅限于减少人口，估计在较大的生产系统中，这将花费超过1,500万加元。展望未来，为了防止加拿大各地进一步的损失，开发有效的预防和控制方法至关重要。本文提出的工作目标是研究预防和控制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。我们将采用尖端的研究工具（如转录组学）来描述S. zoo感染猪的方式和地点，并利用这些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.