The International Thoroughbred Breeders Federation, International Collating Centre, Newmarket, United Kingdom, and other sources reported the following equine disease events in 3Q 2021.
- African horsesickness was reported as endemic in the Republic of South Africa (RSA). One case was confirmed in Gauteng Province.
- Canada, the UK and the USA recorded equine influenza. The number of outbreaks ranged from one (Canada), three (the UK), to single or multiple outbreaks in 23 states in the USA, where the disease is endemic.
- Outbreaks of strangles were reported by Belgium (one), France (22), Germany and the Netherlands (two apiece), Switzerland (five) and the USA (25), where the disease was diagnosed in eight states and is considered endemic.
- Equine herpesvirus type 1 (EHV-1) respiratory disease is endemic in most countries. Infection was confirmed by Germany (two outbreaks), the RSA (nine cases involving outbreaks on three premises), and the USA (one outbreak).
- Outbreaks of EHV-1 abortion were reported by Germany (one) and the USA (two), all represented by individual cases.
- Cases of EHV-1 neurologic disease were confirmed by Argentina (four on one premises), Canada (one), Germany (two outbreaks, one involving five cases), the RSA (one of nosocomial infection), and the USA (six outbreaks, one involving several animals that had attended a show and the remainder by individual cases).
- Equine herpesvirus 4 (EHV-4) respiratory disease was recorded by France, Germany, Italy, the Netherlands, RSA and Switzerland. The number of outbreaks ranged from one (Italy, RSA), two (Germany, the Netherlands and Switzerland) to four (France). The majority of outbreaks involved a single case.
- The USA reported cases of infection with equine herpesvirus-2 and -5 (EHV-2/EHV-5). EHV-2 (18) and EHV-5 (25) infections were diagnosed in five states, some associated with respiratory disease.
- Infection with equine arteritis virus was recorded by France. A 3-year-old colt and a stallion were involved.
- The USA diagnosed 11 single cases of Rhodococcus equi-related respiratory disease.
- Equine infectious anemia (EIA) was confirmed by Canada, Italy and the USA. The number of outbreaks varied from three (Canada), six (USA) to eight (Italy). The majority of outbreaks were comprised of single cases. The outbreaks in the USA involved American Quarter Horses in Texas and feral horses in Utah.
- Equine piroplasmosis was reported by Japan (single clinical case of Theileria equi infection at the Olympic Games in Tokyo) and the RSA. The disease is considered endemic in the RSA, with a total of 38 cases confirmed in five premises, of which 26 were recorded in Gauteng Province.
- Multiple outbreaks of contagious equine metritis (CEM) were recorded by Germany, three had two cases each, and the remaining 10 had a single case. Six of the outbreaks involved stallions, and seven outbreaks involved mares.
- The USA reported a case of equine coital exanthema (equine herpesvirus type 3) and single cases of leptospiral abortion and renal disease in Kentucky.
- The USA also diagnosed 20 cases of Salmonella infection involving serogroup B and five cases of untyped Salmonella spp.
- Clostridial enterocolitis associated with Clostridium perfringens was reported by Switzerland (one case). The USA recorded 11 cases of C. perfringens and three cases of Clostridiodes difficile, the majority in Kentucky.
- The USA confirmed nine outbreaks of Neorickettsia risticii infection involving four states.
- Rotavirus diarrhea in foals was reported by France (six outbreaks, primarily single cases) and the USA (two cases of rotavirus Type A infection).
- One case of equine rabies was confirmed in Montana, USA. This marked the 12th case of rabies in animals in the state in 2021.
- Canada and the USA recorded cases of Eastern equine encephalomyelitis (EEE). Five outbreaks were diagnosed in Canada and 28 in the USA. With two exceptions, the outbreaks consisted of single cases. The majority of cases were in unvaccinated horses.
- Outbreaks of West Nile virus (WNV) encephalitis were reported by Canada (three), Germany (seven), Italy (two, one involving lineage 2 virus), Portugal (three), Spain (six), United Arab Emirates (one), and the USA (58 cases in 15 states).
- Equine encephalosis is considered endemic in the RSA, and two cases were confirmed in the Western Cape Province.
- Three cases of equine protozoal myeloencephalitis were diagnosed in Kentucky, USA.
- Kazakhstan, Spain and the USA reported cases of anthrax. The disease affected horses, cattle and sheep on a farm in Kazakhstan. Of 115 horses, 10 developed disease and nine died. Three cases were confirmed in Spain and one in Texas; the latter represented the third case in Texas in 2021.
- Switzerland diagnosed three outbreaks of intercurrent anaplasmosis and ehrlichiosis in separate Cantons.
This report was first published in the January 2022 Equine Disease Quarterly from the Gluck Equine Research Center at the University of Kentucky.
