Clinical presentation, diagnostic findings, and outcome of adult horses with equine coronavirus infection at a veterinary teaching hospital: 33 cases (2012–2018)

Abstract

Equine coronavirus (ECoV) is a recently described enteric virus with worldwide outbreaks; however, there are little data available on clinical presentation, diagnosis, and outcome. The study objective was to document case management of ECoV in adult horses presented to a referral hospital and compare to a cohort of horses that tested negative for ECoV. A retrospective case series was performed based on positive real-time quantitative PCR results for ECoV on faeces from horses treated at the UC Davis Veterinary Medical Teaching Hospital from 1 March 2012 to 31 March 2018. Horses negative for ECoV were matched to the ECoV-positive group as controls. Data collected included signalment, history, exam findings, diagnostics, treatment, and follow-up.Thirty-three horses (median age, 11 years; range, 2-37 years) tested ECoV-positive, including three horses with co-infections. Presenting complaints for ECoV-infected horses included historic fevers (n = 25/30; 83%), anorexia (n = 14/30; 47%), and colic (n = 13/30; 43%). ECoV-positive horses had significantly lower white blood cell (median, 3.0 Â 10 9 /L; range, 0.68-16.2 Â 10 9 /L), neutrophil (median, 1.26 Â 10 9 /L; range, 0.15-14.4 Â 10 9 /L), and lymphocyte (median, 0.86 Â 10 9 /L; range, 0.42-3.47 Â 10 9 /L) counts than ECoV-negative horses. Electrolyte and metabolic derangements and scant faeces were common. Twenty-seven horses were hospitalised for a median of 5 days (range, 0.5-14 days), with 26/27 (96%) horses surviving to discharge. ECoV infection should be a differential diagnosis for adult horses with fever, colic, anorexia, and leukopenia. The disease has a low mortality rate, but horses may require intensive care to resolve severe leukopenia, systemic inflammation, and metabolic disturbances.

Equine Coronavirus-Associated Colitis in Horses: A Retrospective Study

“…The hepatic lipidosis observed in the Miniature Horse is likely associated with anorexia [10,18]. Liver dysfunction and failure have been reported in ECoV before and may result from endotoxemia and/or bacteremia secondary to gastrointestinal translocation [2,4,7].…”

“…The clinicopathological and transabdominal ultrasound findings were supportive of a diagnosis of colitis in all the horses included in our study. Abnormal ultrasound of the large colon has been previously reported with this infection [4]. Abnormalities of clinical relevance at admission included tachycardia, tachypnea, and hyperlactatemia likely the result of hemoconcentration and/or endotoxemia [2e4, 7,13,15].…”

“…Although the clinical signs and outcomes of horses infected ECoV during outbreaks have been reported in detail [1e3], less is known about the clinical presentation of horses that are infected during a nonoutbreak situation [4]. This study describes the clinical presentation of horses that presented with clinical ECoV infection to a tertiary care facility, but were not associated with a known ECoV outbreak.…”

“…Colic, leukopenia, and changes of fecal character have also been reported [3e5]. Although the clinical signs of horses affected by ECoV during outbreaks has been reported in detail [1e5], less is known about the clinical manifestation of this infection in adult horses in nonoutbreaks situations [4,6]. Thus, the purpose of this study is to describe the clinical presentation of horses diagnosed with ECoV that were admitted to a tertiary hospital, but were not associated with a known outbreak.…”

Development and Validation of a S1 Protein-Based ELISA for the Specific Detection of Antibodies against Equine Coronavirus

“…The morbidity rate varies from 10% to 83% during outbreaks. Mortality is low and has been related to endotoxemia, septicemia or hyperammonemia-associated encephalopathy [12,13]. The outbreaks in adult horses demand further studies on the pathogenesis and epidemiology of ECoV infections.…”