equine diseases
The International Collating Centre, Newmarket, U.K., and other sources reported the following equine disease outbreaks during the third quarter of 2018.

The Republic of South Africa (RSA) reported isolated cases of African horse sickness in known infected areas that included the provinces of the Eastern Cape, Gauteng, and KwaZulu-Natal. Occurrence of the disease is as expected for this time of year.

Equine influenza was recorded in Ecuador (one outbreak), France (three outbreaks), and the U.K., which considers the disease to be endemic. The disease is also endemic in the U.S., being confirmed in seven states, with some outbreaks characterized by multiple cases of the disease.

Canada, France, Germany, Ireland, Switzerland, the U.K., and the U.S. reported multiple outbreaks of strangles. The number of confirmed outbreaks/cases included two in Canada, 28 in France, four in Germany, five in Ireland, and four in Switzerland. The disease was reported to be endemic in the U.K. and in the U.S., where 34 outbreaks were confirmed in 18 states involving at least 68 affected horses.

Equine herpesvirus-1 (EHV-1) related diseases were recorded by France, Germany, Ireland, Japan, the RSA, the U.K., and the U.S. Febrile illness was reported by the RSA and the U.S. Respiratory disease was confirmed in France (eight outbreaks), Germany (one outbreak), the RSA (one outbreak), and the U.K. (one outbreak). Abortion due to EHV-1 was recorded in France (two cases), Germany (single cases on two premises), Ireland (single cases on four premises), Japan (two cases on separate premises), and the U.S. (five cases). The RSA, U.K., and U.S. reported outbreaks of EHV-1 myeloencephalopathy. The RSA and the U.K. each reported a single case of the disease, whereas the U.S. confirmed four cases involving premises in Arizona and California.

Equine herpesvirus-4 (EHV-4) respiratory disease was diagnosed in France (26 outbreaks), Germany (one outbreak involving four cases of the disease), the U.K. (seven outbreaks), and the U.S. (one case). One case of EHV-4 abortion was confirmed in the U.S.

Multiple cases of equine herpesvirus-2 and/or -5 infection were reported in the U.S., some associated with evidence of respiratory disease.

France recorded one case of subclinical equine arteritis virus infection and two cases of abortion caused by the virus. Germany confirmed the carrier state in one stallion.

Equine infectious anemia was diagnosed in Canada (three cases), France (one case), and the U.S. (three cases in Colorado and two in Texas).

The RSA and Switzerland reported cases of equine piroplasmosis. The disease is endemic in the RSA with cases confirmed in six provinces. One case of Theileria equi was diagnosed in Switzerland.

Contagious equine metritis was recorded by Germany (two stallions on separate premises) and South Korea (13 positive venereal swabs from 2,236 stallions and broodmares tested as part of a national survey).

The U.S. confirmed four cases of leptospiral abortion and two cases of equine neorickettsiosis (which causes Potomac horse fever) abortion in Kentucky.

Germany reported one case of salmonellosis (serogroup not specified).

An outbreak of rotaviral enteritis was recorded by Argentina. In involved 10 2- to 4-month-old foals on one premises, all of which had been vaccinated.

The U.S. reported eight cases of infection with Lawsonia intracellularis in Kentucky.

The fourth quarter of 2018 saw a sharp decline in the number of cases of Eastern equine encephalomyelitis confirmed in the U.S., with only three cases recorded, all in New York State.

West Nile virus activity was reported in Canada (3 cases), France (3 case), Portugal (1 case), Tunisia (7 cases), Turkey (1 case), and the U.S. (70 cases).

Rhodococcal-related disease is endemic in the U.S. Even though only three outbreaks were recorded in the fourth quarter, this is not reflective of the true incidence of the disease.

Singapore confirmed one case of Old World screwworm infection in a horse, and Switzerland reported more than four cases of atypical myopathy during October 2018.

This is an excerpt from Equine Disease Quarterly, funded by underwriters at Lloyd’s, London.