Equine Infectious Diseases Research Program

Our Research

EQUID research projects are currently focused on three extremely important infectious diseases of horses:

Rhodococcus equi (R. equi) are bacteria that cause life threatening pneumonia in young horses and account for up to 3 percent of all foal deaths. We have made significant progress identifying novel bacterial targets for protective “killer cell” immune responses. These immune killer cells can eliminate R. equi infected cells from the lungs. Taking this information to the next level, we are working toward developing a new oral vaccine that will enhance the protective immune response in young foals. Such a vaccine would have a tremendous impact on improving the health of young horses all over the world.

Equine infectious anemia virus is widespread throughout the world and causes the disease equine infectious anemia (EIA), which is characterized by fever, anemia, chronic weight loss, and sometimes death. It is spread by horseflies and deerflies, and once infected, horses are infected for life. EIA is regulated and reportable in the U.S., and infected horses must be quarantined for the rest of their lives or euthanized. Currently, there is no vaccine available in the United States. Four decades of ongoing research at WSU has led to a more rapid and sensitive diagnostic test, and resulted in a better understanding of how the equine immune system controls the virus.  Our work is currently identifying important immune targets for potential vaccines using the latest technology. Because the EIA virus is closely related to the human immunodeficiency virus (HIV), our efforts to benefit horses may also help in the effort to develop an effective vaccine against AIDS in people.

Theileria equi (Babesia equi) is a tick-borne blood parasite that causes the disease equine piroplasmosis. Infections result in fever, lethargy, and anemia, which occur for various lengths of time. Severe infections can result in death. Horses that survive are infected for life and can spread the infection to other horses. Although this extremely serious disease had been considered rare in the U.S., recent outbreaks indicate that our horse population is at risk. Like equine infectious anemia (EIA) above, equine piroplasmosis is a reportable disease and infected horses must be quarantined for the rest of their lives or euthanized. We have a long track record working on this disease, and our group developed the diagnostic test that is used throughout the world. During the current U.S. outbreak, EQUID faculty have taken the lead in providing regulatory and scientific support to limit the spread of infection and finding long-term solutions. Research is ongoing, but our data suggest that persistently infected horses can be cured with treatment and no longer pose a risk to other horses. This work could provide relief to owners of quarantined horses not wishing to choose the option of euthanasia. We are currently investigating mechanisms of protective immunity against T. equi, and plan to use what we learn to develop an effective vaccine.