A vaccine against strangles – how effective is it in horses?

Background

Strangles, caused by Streptococcus equi subspecies equi (S. equi), is a highly contagious disease that affects horses worldwide. Vaccination is an important strategy for preventing infection and reducing the spread of the disease. Strangvac is a multivalent vaccine developed to induce protective immunity, but a better understanding is needed of how the immune response to the vaccine’s various components looks and functions.

About the projects

Project 1: Immune response to vaccine components in Strangvac

Strangvac is a multivalent vaccine against strangles that contains five antigens from S. equi. To understand how the vaccine provides protection, it is necessary to know how the immune system responds to the individual components.

The project aims to map antibody responses to various vaccine components following vaccination, analyze how these responses develop over time, and compare the immune response in horses with natural immunity. The project also includes studies on how immunity can be transferred from mare to foal, as well as the development of methods for detecting antibodies in alternative sample materials, such as saliva. The goal is to identify which components contribute most to protection and how the immune response varies.

Project 2: Functional mechanisms and interactions between bacteria and the host

S equi uses various mechanisms to interact with host proteins and evade the immune system. Certain vaccine components are linked to these functions.

The project aims to study the functional properties of specific vaccine components, such as their ability to bind to host proteins (e.g., alpha-2-macroglobulin and albumin), as well as how antibodies can block these interactions. The goal is to improve our understanding of the molecular mechanisms underlying immunity and infection.

Project 3: Disease control, vaccination, and attitudes among horse owners

Although a vaccine against strangles is available, the percentage of vaccinated horses remains relatively low. The spread of the disease is influenced by both biological factors and how horse owners manage disease control and vaccination.

The project aims to use a survey to examine biosecurity practices within the equine population and attitudes toward vaccination. The focus is on identifying factors that influence decisions regarding vaccination and infection control. The goal is to contribute knowledge that can be used to improve preventive measures against strangles.

Collaborations

In addition to the participants at SLU, the research group also includes the following:

• Andrew Waller (Intervacc AB)

Publications related to the project