International Equine Disease Report Third Quarter 2011

The International Collating Center, Newmarket, United Kingdom, and other sources reported the following disease outbreaks:

Contagious equine metritis (CEM) was reported from France (one case), Germany (one case), and South Africa, which confirmed the carrier state in five stallions, each on separate premises, presumably exposed through indirect contact with a carrier stallion imported in February 2011.

Italy diagnosed a mild case of dourine in one mare.

Three cases of coital exanthema caused by equine herpesvirus-3 (EHV-3) were confirmed in the U.K.

Equine influenza was reported from Ireland, the U.K., and the United States. The disease was diagnosed in four horses on one premises in Ireland. Two outbreaks of H3N8 virus, clade 2, Florida sublineage, American lineage were recorded in the U.K., and the United States confirmed three outbreaks on individual premises in Kentucky and New York.

Strangles was reported from Chile, Ireland, Italy, Singapore, South Africa, Sweden, Switzerland, the U.K., and the United States. In Chile, Italy, and Singapore, the disease occurred as sporadic or isolated cases. In the other listed countries, strangles is considered endemic.

Chile, Germany, and the United States confirmed cases of EHV-1 and EHV-4 respiratory disease. In Chile, both viruses were detected in three out of 150 vaccinated horses on one premises. Germany and the United States reported isolated cases on individual premises. EHV-1 abortions were reported from France, Germany, Ireland (one case each), and South Africa.

EHV-1 myeloencephalopathy was reported from the United States. Five separate outbreaks were confirmed: three in California and one each in Michigan and Tennessee. All of the strains of EHV-1 that were detected had the neuropathogenic genomic motif.

The United States recorded association of EHV-2 with respiratory illness in six horses on one premises. Equine arteritis virus infection was reported by France (one clinical case) and Germany (carrier state in a stallion).

Equine infectious anemia was reported from Italy (endemic) and Japan (12 cases).

Equine piroplasmosis (EP) was reported from France, South Africa, Switzerland, the United Arab Emirates (UAE), and the United States. The disease is considered endemic in France, South Africa, and the UAE. Two clinical cases were diagnosed in Switzerland. The United States reported an estimated 20,000 horses were serologically screened for EP infection during the third quarter of 2011, of which five were confirmed seropositive for Theileria equi. One infected animal had been imported from Mexico; infection was considered to be iatrogenic (inadvertent complications resulting from medical treatment) and not by tick transmission.

Thirty-eight cases of Eastern equine encephalomyelitis were diagnosed in the United States: 20 in Wisconsin and the remainder of the cases in New York, Florida, Michigan, Louisiana, and North Carolina. West Nile encephalitis cases were reported in the United States (52) with 11 in California, nine in Pennsylvania, and the remainder in 19 other states.

Australia reported a very significant increase in the incidence of neuro-invasive disease due to infection with Kunjin virus, a lineage 1 strain of West Nile virus. New South Wales and Victoria were most severely affected, with over 250 neurologic cases each. Queensland, Northern Territory, and Western Australia also reported cases. The case fatality rate varied between 10 and 15%.

Cases of Murray Valley encephalitis were reported in Queensland and New South Wales. Infection with Ross River virus was seen in a limited number of horses in Tasmania. One equine case of Hendra virus infection was confirmed in Queensland.

Germany recorded single cases of rotavirus and Salmonella infection. The United States confirmed three outbreaks of Clostridium perfringens type A diarrhea in foals, 21 cases of equine monocytic ehrlichiosis, and four outbreaks of Lawsonia intracellularis enteropathy.

Three mild cases of anaplasmosis due to A. phagocytophilum were confirmed in Switzerland, which also reported eight cases of equine grass sickness on four premises.

*Second Quarter Report for Australia

This is an excerpt from Equine Disease Quarterly, funded by Lloyd's of London underwriters, brokers, and their Kentucky agents.

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Equine Disease Quarterly

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