Newsdate: Friday, March 3, 2023 - 11:00 am
Location: LEXINGTON, Kentucky
The international report on equine infectious diseases reported as urgent a multiple-state botulism outbreak among horses was reported in the United States of America with affected herds in Louisiana, Texas, Colorado and New Mexico.
Horse quarantined in stall
Quarterly international infectious disease reports contain a concise report on major infectious diseases throughout the equine world.
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The source of the toxin (see also article on equine botulism) has been traced to alfalfa cubes produced by Colorado-based Manzanola Feeds and labeled as ‘Top of the Rockies’ Alfalfa Cubes. The product consists of 1-inch cubes, packaged in 50 lb/22.7 kg bags and labeled with the following codes: 111222, 111322, 111422, 111522 and 111622.
The following report was composed with information provided by the University of Kentucky Veterinary Diagnostic Laboratory and Equine Diagnostic Solutions, Inc.—both in Lexington, Kentucky; IDEXX Laboratories, Germany; the International Thoroughbred Breeders Federation; the International Collating Centre in Newmarket, United Kingdom; and by the American Association of Equine Practitioners’ Equine Disease Communication Center.
This report is retrospective and does not claim to be complete. However, it provides an indication of heightened activity of relevant contagious or environment- linked diseases among equids. To further improve this data, it is encouraged to report laboratory- confirmed diseases of Equidae to the ICC.
Strangles is still the most consistently reported disease from various regions across North America and Europe, including the British Isles. Reporting included laboratory confirmed farm outbreaks as well as samples submitted to various laboratories.
Few outbreaks of equine influenza virus were reported from regions of North America and from various parts of Europe during the third quarter. Outbreak numbers increased significantly during the fourth quarter compared to third quarter for both areas.
Equine herpes virus (EHV) -4 or -1 respiratory disease was reported infrequently in the USA and more often from operations in the UK, Ireland and continental Europe for both quarters.
During the third quarter, one EHV abortion was reported from Japan and three from Argentina. For the latter country, one would expect a pregnancy in the third trimester, which is the most vulnerable period for EHV-1 associated abortion.
During the fourth quarter, three abortions were reported in Kentucky (USA) and one in continental Europe. Equid herpesvirus- associated myeloencephalopathy (EHM) follows a seasonal pattern with the majority of outbreaks associated with the cooler times of the year (first, second and fourth quarters in the Northern Hemisphere).
Hence, only a few (four single case) outbreaks were reported from North America and one from the UK during the third quarter.
In addition to seasonality, EHM outbreaks are extremely rare in the Southern Hemisphere. It is therefore noteworthy to report a single case of EHM at the San Isidro racecourse in Buenos Aires, Argentina.
EHM outbreak frequencies changed as expected for the fourth quarter with 10 EHM outbreaks reported in North America, three outbreaks in continental Europe and one outbreak in the UK.
Within Kentucky, a single case of EHM was detected in a barn at Churchill Downs racecourse in Louisville. Several other horses from the same barn were found shedding EHV-1; however, no further horse developed EHM.
Noteworthy, during the fourth quarter, information of a (large scale) EHV-1 outbreak with EHM and abortions involving multiple herds was received from the Punjab region of India. However, this information is awaiting official reporting as diagnostic laboratory results have not yet been shared.
A little more than 20 equine infectious anemia (EIA) virus positive animals (with rarely two animals simultaneously on a farm) were identified in North America. Cases were evenly distributed over the third and fourth quarters.
There were also reports of EIA from Italy (three reports) and Hungary (one report). Increased vector activity during the third quarter was likely the cause for the relatively high case numbers of alphavirus encephalitis (exclusively Eastern equine encephalitis) reported in the USA and Mexico (one case).
Flavivirus, mainly West Nile virus (WNV), activity was increased for distinct areas of Europe and Northern Africa.
Countries that border the Mediterranean basin reported approximately 35 cases; Algeria, Greece and Tunisia each reported a single case of WNV.
Most Mediterranean basin cases were reported from Italy. Germany reported nine confirmed cases from its central and north eastern states.
Miscellaneous: Contagious equine metritis (CEM): Mostly single cases on 14 premises in Germany and France tested positive for Taylorella equigenitalis, the causative agent of CEM.
Additionally, a single case of African horse sickness was reported from Sub-Saharan Africa (Nigeria); a case of rabies was reported in the USA; and a case of Hendra virus infection was reported from Australia.
Author of Article: Lutz Goehring University of Kentucky Gluck Equine Research Center
Article from Equine Disease Quarterly - Maxwell H. Gluck Equine Research Center Lexington, Kentucky USA,