Immune-mediated thrombocytopenia associated with angiostrongylus vasorum infection in a Jack Russell terrier

Thrombocytopenia is the most commonly occurring platelet disorder in dogs [14], with a prevalence rate among the admissions to one US hospital of approximately 5% [20]. Thrombocytopenia may result from a variety of pathophysiological mechanisms including reduced platelet production, increased platelet sequestration, increased platelet utilisation or destruction [8].Immune-mediated thrombocytopenia (IMTP) is a disease characterised by the premature destruction of antibody-coated platelets by macrophages [30]. This disease may occur as a primary disease, termed primary IMTP or idiopathic thrombocytopenic purpura, or as a secondary disease associated with conditions such as neoplasia, inflammation or infection [30]. The pathogenesis of primary IMTP is thought to involve the production of antibodies directed against normal host platelet-surface antigens, whereas in secondary IMTP the pathogenesis remains largely undefined [30].Angiostrongylus vasorum is a metastrongyloid nematode that parasitises dogs and other Canidae via an indirect lifecycle involving slugs, snails and frogs that act as intermediate or paratenic hosts [2,41]. This life cycle has been extensively reviewed elsewhere [41,2]. The first report of Angiostrongylus vasorum infection in Ireland was in a Greyhound [40]. Following this, the infection became well-recognised within Greyhound kennels in Ireland [12] and the first reported case in England was a Greyhound that had been imported from Ireland [23]. More recently, Angiostrongylus vasorum infection has been reported in several pet dogs in Ireland [5]; however, the overall prevalence of the nematode in this country is unknown [5].A wide variety of clinical signs have been associated with Angiostrongylus vasorum infection. Commonly reported clinical signs include cardiopulmonary signs such as coughing, exercise intolerance and dyspnoea [38,35,37]. In some cases progression of the signs to right-sided heart failure [21] or sudden death attributed to acute