The following information was provided in April 2021 by the Equine Disease Quarterly from the University of Kentucky’s Gluck Equine Research Center. The Equine Disease Quarterly is funded by Underwriters at Lloyd’s London.
The International Thoroughbred Breeders Federation, International Collating Centre, Newmarket, United Kingdom, and other sources reported the following equine disease events.
The Republic of South Africa (RSA) reported that African horse sickness was endemic except for the controlled area in the Western Cape Province. A limited number of cases were recorded in Gauteng and Mpumalanga provinces.
Canada, France, Germany, the Netherlands, UK and the USA confirmed outbreaks of equine influenza. The number ranged from two (Canada and the Netherlands), three (France, Germany and the UK), to at least 16 in the USA, where the disease is endemic. One outbreak in California involving 40 burros had a very high case fatality rate.
Strangles is considered endemic in many countries with outbreaks confirmed by Belgium (one), Canada (one), France (five), Germany (eight cases), the Netherlands and the USA (13 apiece). The majority of outbreaks were comprised of a single case.
Equine herpesvirus type 1 (EHV-1)-related diseases are endemic in most countries. Outbreaks of EHV- 1 abortion were diagnosed in France and Germany (three each), Japan (five outbreaks involving seven Thoroughbreds, of which six were vaccinated), the Netherlands (two), the UK (one), and the USA (four). EHV-1 neurologic disease was reported by the Netherlands (single case) and the USA (seven outbreaks in California, Florida, Michigan and Oregon). California had three outbreaks involving 11 cases, and single cases were recorded in the remaining states.
Outbreaks of equine herpesvirus type 4 (EHV-4) respiratory disease was reported by Belgium (two), France (14, all but three were single cases), Germany (one), the Netherlands (three, one involving four foals), and the USA (numerous states, mostly in foals).
Germany and the USA recorded cases of equine herpesvirus type 2 and/or type 5 infection. Infections were associated with respiratory disease in both countries and one case of EHV-2-associated keratitis in Germany.
Equine infectious anemia was confirmed in Romania (one outbreak, two cases) and the USA (six outbreaks, five involving single cases and one involving two cases), all in Texas.
The RSA recorded that equine piroplasmosis was endemic, occurring sporadically in eight provinces. Highest numbers were diagnosed in Gauteng and Western Cape provinces.
Germany reported a case of equine arteritis virus infection in a Warmblood stallion and Taylorella equigenitalis carrier state in three Icelandic stallions.
Several cases of nocardioform placentitis and abortion due to Amycolatopsis spp. or Crossiella equi were confirmed by the USA.
France, Switzerland and the USA recorded cases of leptospirosis. France (a case) and the USA (two cases) diagnosed cases of abortion. France also confirmed two outbreaks (single cases) of uveitis. Switzerland recorded a case of leptospirurea.
The USA recorded one case of Neorickettsia risticii abortion and three other outbreaks in which horses presented with fever, anorexia, depression and diarrhea.
Salmonellosis was reported by the USA (three cases, two involving serogroup C1 and one of undetermined serogroup).
Rotaviral diarrhea was reported by Argentina (one outbreak involving 40 vaccinated 20- 40-day-old foals) and the USA (one case).
Clostridial enterocolitis was reported by the USA; nine cases were associated with Clostridium perfringens and two with Clostridiodes difficile.
The USA confirmed 13 cases of proliferative enteropathy caused by Lawsonia intracellularis.
Canada (two outbreaks) and the USA (22 outbreaks) confirmed cases of Eastern equine encephalomyelitis (EEE), all were single cases. A case of dual infection with EEE and West Nile viruses was diagnosed in a vaccinated horse in Florida.
Outbreaks of West Nile virus infection were reported by Austria, France and Italy (two outbreaks each, all single cases), Germany (four outbreaks), Spain (11 outbreaks) and the USA (16 outbreaks, all single cases).
Two outbreaks of vesicular stomatitis, Indiana serotype, were confirmed by the USA in Texas and Missouri.
Rhodococcus equi-related diseases were reported by Germany (two cases of bronchopneumonia in foals), and the USA, where the disease is endemic and widespread.
Canada (one case) and the USA (11 outbreaks in Washington State) recorded occurrences of Pigeon fever, Corynebacterium pseudotuberculosis infection.
Japan recorded one case of tetanus.