An outbreak of foal yersiniosis in Poland: pathological and bacteriological examination.

The research article investigates an outbreak of foal yersiniosis, a bacterial disease, in Poland that resulted in the death of 10% of foals at a stud-farm in 1995, and discusses the subsequent treatment and vaccination of the surviving horses to control the outbreak.

Overview and Purpose of the Study

• The study’s primary focus was to investigate an outbreak of a rare bacterial infection known as foal yersiniosis, which occurred in Poland in 1995. Yersiniosis is caused by the bacterium, Yersinia pseudotuberculosis.
• After the disease resulted in the death of 10% of the foals at the stud-farm, the researchers sought to identify the specific cause of death and subsequently manage the outbreak.
• The investigation involved pathological and bacteriological examinations of the dead foals to identify the bacterial strain causing the infection and understand its pathogenicity.

Key Findings

• Upon examining the internal organs of three dead foals, the researchers discovered a profuse growth of an enterotoxigenic strain of Yersinia pseudotuberculosis.
• The foals who died had shown clinical symptoms of pneumonia and watery diarrhoea – typical signs of yersiniosis.
• The widespread presence of the bacteria in the internal organs indicated that this was the likely cause of the outbreak, leading to the high mortality rate at the stud-farm.

Treatment and Control Measures

• Following the identification of the disease and causative bacteria, the researchers implemented a treatment and control protocol for the foals that had clinical symptoms of yersiniosis.
• The first step involved immunizing the foals with clinical symptoms using Propionibacterium acnes t. II, a bacteria known for its immunomodulatory properties.
• Then, all mares and their offspring at the stud-farm were treated with the same immunomodulator.
• After the immunomodulator treatment, the livestock were vaccinated with a formalin-inactivated culture of Yersinia pseudotuberculosis – the bacteria causing the disease. Formalin inactivation is a process used to kill bacteria while maintaining antigens that could stimulate an immune response in the body. Using an inactivated culture of the disease-causing bacteria for vaccination helps build immunity against the bacteria.