Detection of equine coronavirus in horses in the United Kingdom

Equine coronavirus (ECoV) is a Betacoronavirus that has been associated with disease in individual animals and groups of horses, and over the past seven years has been increasingly reported as a cause of disease outbreaks—primarily in adult horses in the USA and Japan.1–3 The main clinical signs associated with infection in adult horses are anorexia, lethargy and fever, with diarrhoea and mild colic signs less frequently reported.2 3 More serious complications associated with infection include septicaemia and encephalopathy associated with hyperammonaemia, however these complications are rare and most horses recover with supportive care.3 4 Leucopenia with lymphopenia and/or neutropenia are the main haematological abnormalities reported in clinical adult cases.3 The virus primarily infects the small intestinal mucosa causing enteritis, and a faeco-oral route of transmission is suspected.5–7 Clinically affected horses have been shown to shed virus in their faeces for up to 11 days and ECoV has also been detected in the faeces of small numbers of healthy adult horses on premises where disease outbreaks have occurred.3 4 qPCR testing of faeces is a sensitive diagnostic method to confirm ECoV infection. One study determined 90 percent accuracy between clinical status and PCR detection of ECoV infection in disease outbreaks.3 Peak faecal shedding has been shown to occur three to four days after the development of clinical signs and there have been a few cases of early ECoV infection that have tested qPCR negative; however, these horses tested positive 24–48 hours later and repeat testing of a …