The Thoroughbred industry became threatened by a new genital infection in 1977. This new disease, contagious equine metritis (CEM), was first reported during the 1977 breeding season in England. Shortly thereafter, the disease was reported in Ireland, Australia, and France as well. Cases of the disease had been seen in Ireland in 1976 but apparently had not been reported.
"Haemophilus equigenitalis: The Agent of CEM,"
Iowa State University Veterinarian: Vol. 41
, Article 4.
Available at: https://lib.dr.iastate.edu/iowastate_veterinarian/vol41/iss3/4