Parasitological, clinical and serological examinations on the progress of Parascaris equorum infections in foals

Abstract

acid by real-time RT-PCR. All ECoV positive horses in this study were older than one year. In addition to diarrhea, clinical presentation of ECoV PCR positive horses included colic and pyrexia. The most common laboratory abnormality was neutropenic leukopenia. The 525 fecal samples negative for ECoV serves as strong control showing that ECoV is not a common incidental finding in horses fecal samples. 16/35 horses were from outbreaks (clusters of more than one horse with a positive clinical presentation and positive ECoV PCR result within a single farm). 3/16 horses associated with outbreaks tested positive for coinfections with Cryptosporidium species, but all 3 were associated with horses only positive for ECoV within the same farm. Of the 35 total ECoV positive horses, 8 were coinfected: 4 with cryptosporidium species, 1 with equine rotavirus, 1 with C. difficile toxin A & B, 1 with C. perfringens enterotoxin A, and 1with salmonella species. ECoV outbreaks were identified in 4 states: CA, WA, ID, and NJ. ECoV was successfully isolated frommultiple fecal samples submitted from outbreaks in ID and WA. Sporadic ECoV PCR positive cases with clinical signs were found in 11 states: CA, TX, MI, PA, ID, MT, NM, NJ, VA, NH, and WA. The presence of clinical signs, laboratory abnormalities and the molecular and virological findings suggest that ECoV is associated with diarrhea outbreaks in adult horses. Results of this retrospective study indicate that ECoV should be considered as an important enteric, potentially contagious, viral pathogen of adult horses. More experimental study is needed to better define the virulence and pathophysiology of US ECoV strains in horses to further the understanding of coronavirus infections in the horse.