Animal Health News

Recently the Cornell Animal Health Diagnostic Center (AHDC) added Salmonella culture to its Equine Fever of Unknown Origin PCR Panel (test code EFUOP). This panel is designed to screen horses for pathogens that may cause fever in the absence of localizing clinical signs. While Salmonella is known to cause severe toxic enterocolitis in horses, it can also present as fever prior to the development of mild gastrointestinal signs/shedding or peracute septicemia with fever, anorexia and depression in the absence of gastrointestinal signs.¹

In addition to screening for Salmonella, the Equine Fever of Unknown Origin Panel uses PCR to test for the gastrointestinal pathogens beta coronavirus and Neorickettsia risticii, respiratory pathogens Streptococcus equi subsp. equi, equine influenza virus type A, equine rhinitis virus types A and B, equine adenovirus type 1, equine arteritis virus and equine herpesvirus types 1 and 4, and the tick-borne pathogen Anaplasma phagocytophilum. This panel requires the submission of 3 sample types, including feces or colon contents, a respiratory sample (nasal swab, nasopharyngeal wash or lung) and EDTA whole blood or spleen (post-mortem).

Over the 6 months following the addition of Salmonella culture to the Equine Fever of Unknown Origin Panel, 304 submissions were received, of which 9 (∼3%) were culture positive for Salmonella enterica. Affected horses averaged 12 years in age (range: 6 months–27 years), with no breed or sex predisposition. Fever was the only reported clinical sign in cases with a history provided. S. enterica was the sole pathogen identified in 6 of these cases, of which the most common serovar was Typhimurium (3 cases), followed by Newport (2 cases) and Welsco (1 case). Co-infections were identified in 3 additional cases where horses were infected with both S. enterica and one of the following panel pathogens: Streptococcus equi subsp. equi, Neorickettsia risticii (the causative agent of Potomac Horse Fever) or Equine Adenovirus Type 1. The S. enterica serovars involved in these co-infections included 4,[5],12:i:- (2 cases) and Thompson (1 case).

For more information about the Equine Fever of Unknown Origin Panel, view the AHDC test and fee catalog entry, read the announcement on our website or contact a Veterinary Support Services veterinarian at (607) 253-3900.

References

1. Sellon DC, Long MT. Equine Infectious Diseases. 2nd ed. Elsevier; 2013.