The Strangles Vaccine, Strepvax II, is an IM injectable killed vaccine give to horses to prevent Strangles. Strangles is a highly contagious disease of horses caused by Streptococcus equi subspecies equi (S. equi var. equi). It is a bacterium which causes the highly contagious disease strangles (also known as “distemper”). Strangles commonly affects young horses (weanlings and yearlings), but horses of any age can be infected. Vaccination against S. equi is recommended on premises where strangles is a persistent endemic problem or for horses that are expected to be at high risk of exposure. Following natural infection, a carrier state of variable duration may develop and intermittent shedding may occur. The influence of vaccination on intermittent shedding of S. equi has not been adequately studied.
The vaccine is a killed vaccine. It is a Streptococcus Equi Bacterial Extract
For use in healthy horses of all ages as an aid in the reduction of disease (strangles) due to Streptococcus equi infection.
- Promotes phagocyte destruction of virulent S equi
- Reduced risk of sensitization; well tolerated by most horses
- Contains a purified M-protein antigen extracted through an exclusive process
- Sensitizing elements of whole cell bacterins are virtually excluded in the extraction process
- Available in 1 mL dose and 10 mL dose
- The only S. equi vaccine that can be administered IM.
- A purified M-protein antigen extracted through an exculsive process which promotes destruction of virulent S. equi.
- Exclusion of sensitizing irritants of whole cell vaccines of the past, reducing the risk of vaccine reactions.
- Does not require reconstitution or intranasal injection, making Strepvax an attractive option for practitioners who desire convenience and ease-of-administration.
- Killed vaccine with no risk of reversion to virulence.
Field reports suggest certain hypersensitive horses may demonstrate local or generalized reaction, sometimes severe, following exposure to streptococcal proteins. Studies indicate exercise following vaccination decreased incidence and duration of reactions.
Killed vaccines are an adjunct to the prevention of strangles. Vaccination with these products should not be expected to prevent disease. However, appropriate pre-exposure vaccination with these products appears to attenuate the severity of clinical signs in affected horses, should disease occur, and has been shown to reduce the incidence of disease by as much as 50% during outbreaks.
All injectable, inactivated S. equi. vaccines, can be associated with an increased rate of injection site reactions as compared to other equine vaccines. Due to the limited variability between commercially available vaccinal bacteria and field isolates, autogenous bacterins are not advocated.
Adult horses previously vaccinated: Vaccinate every 6 to 12 months based on risk assessment and manufacturers’ recommendations.
Adult horses unvaccinated or having unknown vaccinal history
Manufacturers’ recommendations are for primary vaccination with a series of 2 or 3 doses administered at intervals of 2 to 4 weeks, depending on the product used, followed by annual revaccination. Revaccinate at 6- month intervals, regardless of the injectable product used.
Broodmares previously vaccinated
Vaccinate 4 to 6 weeks pre-partum with approved products that contain inactivated M-protein. Maternal antibody interference is not known to occur when injectable, M-protein vaccines are administered.
Broodmares previously unvaccinated or having unknown vaccinal history
Administer primary series of killed vaccine containing M-protein (see above, Adult horses unvaccinated) with final dose to be administered 4 to 6 weeks pre-partum.
For foals at high risk for exposure to strangles, administer a 3-dose primary series of an M-protein product beginning at 4 to 6 months of age. An interval of 4 to 6 weeks between doses is recommended.
Horses having been naturally infected and recovered: Following recovery from strangles, most horses develop a durable immunity, persisting in over 75% of animals for 5 years or longer. This indicates that stimulation of a high level of immunity is biologically feasible given appropriate presentation of protective immunogens. Currently, a diagnostic test is available and may be used to assess the level of immunity conferred by natural exposure or vaccination. Since natural exposure or vaccination can provide variable levels of immunity, use of this test may provide a guideline in determining the need for current or future vaccination. Additional testing information is available from; ACVIM Strep equi consensus statement.
USEF Regulations: None Except 12 hour rule.
Returns: Vaccines cannot be returned.