Notes from the Field: Fatal Infection Associated with Equine Exposure – King County, Washington, 2016.

The research article discusses a fatal infection linked with exposure to horses that occurred in King County, Washington, in 2016. The infections were caused by a zoonotic bacterium, Streptococcus equi subspecies zooepidemicus (S. zooepidemicus), typically found in horses and rarely in humans.

About the Streptococcus equi subspecies zooepidemicus

• The Streptococcus equi subspecies zooepidemicus (S. zooepidemicus) is a type of bacterium that is typically found in horses but can occasionally infect humans. It is transmitted through consuming unpasteurized dairy products or through direct contact with horses.
• In horses, this bacterium is commonly present but can occasionally cause respiratory, wound, and uterine infections.
• Although rare, human infection by S. zooepidemicus can result in serious or even fatal outcomes.

The 2016 King County Cases

• On March 17, 2016, Public Health-Seattle & King County was alerted about two persons diagnosed with S. zooepidemicus infections.
• This precipitated an investigation by the health department to assess the spread of the outbreak, identify the risk factors, andprovide recommendations.

Significance and Implications

• This study signals that S. zooepidemicus, although a rare causative agent of human illness, still poses a significant risk, especially for people who have close contact with horses or consume unpasteurized dairy products.
• The health department’s response and investigation highlights the importance of quick action and in-depth research in understanding and managing infectious disease outbreaks.

Research Recommendations

• This research calls for increased vigilance and precautionary measures for those in close contact with horses or those consuming unpasteurized dairy products to limit the spread of S. zooepidemicus in humans.
• Further investigations should be made on the behavior and pathogenicity of S. zooepidemicus to allow for improved prevention and treatment strategies.