Equine Coronavirus in a 12yr old Thoroughbred Gelding Kathryn Golden, DVM Carolina Equine Hospital 5373 NC Highway 150E Browns Summit NC, 27214 Mentor: Mark Wallace, DVM, DACVIM

Signalment and Presenting Complaint 12 yr old Thoroughbred show horse Presented for 2 day history of partial anorexia, lethargy, fever, and mild colic signs

History Patient spent time in Ocala FL 6 weeks prior to presentation 3 days before onset of clinical signs another horse on the property became febrile, lethargic and partial anorexia Resolved with supportive therapy and NSAIDs Patient hospitalized 2 days after onset clinical signs for supportive therapy

Clinical Findings Mild depression Temperature: 102.4oF Heart Rate: 40 beats per minute Respiration:16 breaths per minute, normal auscultation Normal digital pulses Mucous membranes pink with a capillary refill <2 seconds Hypermotile borborygmi Loose stool- semi formed, not cowpie consistency

Diagnostic Work-Up Rectal Examination Rebreathing Examination Scant amount of loose stool Rebreathing Examination Normal bronchovesicular sounds Thoracic and Abdominal Ultrasound Not performed on initial presentation Abdominocentesis Nasal Swab for Respiratory Viruses Due to the infectious nature of the disease and fever of unknown origin, respiratory disease was a top differential www.littmann.com

Additional Diagnostics Complete Blood Count Chemistry and Fibrinogen Fecal Panel- loose stool and infectious nature, concerning for infectious colitis Feces for Equine Coronavirus PCR Due to history of multiple horses affected on property, patient was placed in isolation.

Complete Blood Count Chemistry Fibrinogen Select Parameters for Discussion Hematocrit 35% 32%-50% WBC 4.9x103/ml 5.5-12.5x103/ml Neutrophils 2,205/ul 2,600-7,500/ul Lymphocytes 1,500-7,700/ul Total Protein 6.0g/dL 5.4-7.8g/dL Albumin 3.3g/dL 2.3-3.8g/dL Globulin 2.7g/dL 2.2-4.4g/dL Total Bilirubin 3.7mg/dL 0.8-3.2mg/dL Fibrinogen 180mg/dL 76-230mg/dL Interpretation Hematocrit is within normal limits as well as total protein, indicating appropriate plane of hydration Mild leukopenia with neutropenia Total protein and albumin within normal limits Increased total bilirubin consistent with history of anorexia

Equine Respiratory Panel All horses on the property are regularly vaccinated for EHV 1/4 and Equine Influenza Virus. Due to the high morbidity of this disease with non-specific clinical signs, respiratory disease is an important rule-out.

Fecal Panel NEGATIVE Salmonella and Shigella species Due to the infectious nature of the disease Salmonella was an important rule out, E. coli Serotyping Rotavirus Antigen Clostridium perfringes Enterotoxin Salmonella and Shigella species NEGATIVE a comprehensive fecal profile was the most cost effective option to rule out Salmonella

Equine Coronavirus PCR Photo Source http://www.quantabio.com/product.php?base_id=95064 POSITIVE A positive fecal PCR with a negative respiratory panel and negative fecal panel, is highly suggestive of Equine Corona Virus as the causative agent.

Diagnosis: Equine Coronavirus Abbreviated ECoV Newly recognized illness in horses Seen in the Northeast, most prevalent during colder months RNA virus Implicated in respiratory and enteric disease in other species Photo source: https://ahdc.vet.cornell.edu/news/equine_enteric_coronavirus.cfm

Equine Coronavirus Transmission Survival in environment Fecal oral route Survival in environment Unknown Age Prediliction Adult horses >2yrs of age Morbidity 20-57%, mortality is rare and due to secondary complications Duration Signs usually resolve in 1-4 days with supportive therapy

Changes in fecal character Leukopenia (neutropenia, lymphopenia) Clinical Signs of ECoV Anorexia Changes in fecal character Neurologic abnormalities secondary to hyperammonemia Leukopenia (neutropenia, lymphopenia) Hypoalbuminemia Lethargy Fever <104 Our patients clinical signs are highlighted

Treatment Plan Intravenous Fluids- ongoing loss through loose stool and concern over impending colitis 20L LRS bolus 1.5x maintenance for 2 days NSAID Therapy Flunixin meglumine @1.1mg/kg IV q12hr Gastric Ulcer Prevention ¼ tube Ulcerguard PO q24hr Platinum Performance BioSponge Intestinal adsorbant

Outcome Patient returned home following hospitalization with supportive therapy and returned to work.

Outbreak Summary Within a 2 week period 5 of 6 horses became clinical 3 horses were hospitalized and treated with supportive therapy 3 positive equine coronavirus fecal PCRs from 3 separate patients were isolated Unknown exposure/introduction to herd All horses recovered with supportive therapy and NSAIDs

References Pusterla, N, et al. Emerging outbreak associated with equine coronavirus in adult horses. Veterinary Microbiology. 2013;162:228-231. Yasuhiro, O, et al. Isolation of an equine coronavirus from adult horses with pyrogenic and enteric disease and its antigenic and genomic characterization in comparison with the NC99 strain. Veterinary Microbiology. 2011;150:41-48 Cornell University College of Veterinary Medicine Website (https://ahdc.vet.cornell.edu/news/equine_enteric_coronavirus.cfm)