Equine multinodular pulmonary fibrosis in horses in the UK

EQUINE multinodular pulmonary fibrosis (EMPF) is a relatively recently described condition in horses, characterised by a loss of functional pulmonary parenchyma due to extensive nodular to coalescing interstitial fibrosis; the remaining alveoli are lined by cuboidal epithelium and are filled with inflammatory cells (Williams and others 2007). EMPF was described first in the USA (Williams and others 2007, Hart and others 2008, Wong and others 2008), but more recently has been reported in Europe, in Germany and Austria (Poth and others 2009, Niedermaier and others 2010). A strong association between EMPF and equine herpesvirus type 5 (EHV-5) has been established, although the pathogenesis of the condition is still unclear (Williams and others 2007). EHV-5 is a DNA gammaherpesvirus, which has been detected in the USA, Australia, New Zealand and Europe in nasal swabs and peripheral blood lymphocytes (PBLs) from both healthy horses and those with respiratory signs, at highly variable rates (Agius and Studdert 1994, Reubel and others 1995, Franchini and others 1997, Borchers and others 1999, Dunowska and others 1999, Nordengrahn and others 2002, Bell and others 2006, Wang and others 2007, Torfason and others 2008, Fortier and others 2009). EHV-5 has also been identified in horses in the UK, where PCR yielded a positive result in PBLs from five of 21 healthy adult horses (Nordengrahn and others 2002).This short communication describes two cases of EMPF in the UK, and their association with EHV-5.The first case, an 11-year-old thoroughbred gelding, was presented in February 2010 with a two-week history of lethargy, listlessness and an increased respiratory rate. Radiographic and ultrasonographic examinations (Fig 1a, b) revealed nodular lesions throughout both lungs. The animal was euthanased. At postmortem examination, gross findings in the lungs were consistent …