INTRODUCTION Angiostrongylus vasorum is a meta- strongylid helminth parasite of canids, which infects domestic dogs as well as foxes. The adult worm lives in the pul- monary artery, the right side of the heart or pulmonary arterioles, from where eggs are carried to pulmonary capillaries. The eggs hatch in the pulmonary capillaries and first stage (L1) larvae migrate through the alve- olar epithelium, are coughed up, swal- lowed and passed in the faeces. Within a molluscan intermediate host, the larvae undergo subsequent moults to become third stage (L3) larvae. The life cycle is completed when a dog ingests an interme- diate host and infective L3 larvae are liber- ated into the dog’s small intestine. Frogs may also act as intermediate and paratenic hosts (Bolt and others 1993). A vasorum has a worldwide distribution and within Europe is recognised to be endemic in France, Ireland and Denmark (Bolt and others 1994). Sporadic cases have occurred in many other diverse coun- tries, including the USA, Canada and Brazil (Bolt and others 1994). A vasorum was first reported in the UK in a grey- hound imported from Ireland (Jacobs and Prole 1975). Since then, most reported cases have occurred in dogs from south Wales and Cornwall (Jones and others 1980, Simpson and Neal 1982, Martin and Neal 1992, Patteson and others 1993, Otter and others 1997). Transmission of A vasorum to dogs in south-east England was first reported by Cobb and Fisher (1990) and since then there have been spo- radic but increasing reports of cases in dogs from that area (Elwood 2001, Kriek 2001, Phillips 2001). There have been several reports of indi- vidual cases of A vasorum infection in dogs in the UK (Jacobs and Prole 1975, Cobb and Fisher 1990, Ramsey and others 1996, Gould and McInnes 1999), but only two small case series; Patteson and others (1993) described A vasorum infection in seven dogs from south Wales, Cornwall and Ireland, while Martin and others (1993) reported a further eight cases from Cornwall, two of which were asympto- matic. The clinical signs associated with angiostrongylosis may be diverse and a range of signs is described in the above reports. However, two clinical syndromes predominate; respiratory disease caused by the inflammatory response to eggs and migrating larvae, and haemorrhagic diatheses manifesting as local or diffuse haemorrhages. The mechanism behind the coagulation defects is poorly understood but most authors have suggested that anti- PAPERS P. S. CHAPMAN, A. K. BOAG, J. GUITIAN AND A. BOSWOOD Journal of Small Animal Practice (2004) 45, 435–440 Angiostrongylosis was diagnosed in 23 dogs presenting to the Queen Mother Hospital for Animals between June 1999 and August 2002. The animals’ clinical records were reviewed retrospectively and certain risk factors were compared with a control population of 3407 dogs. Twenty-two of the 23 dogs were from south-east England and dogs from Surrey (n=8) were significantly overrepresented. There were also significantly more Cavalier King Charles spaniels (n=5) and Staffordshire bull terriers (n=5) among the affected dogs than in the control group. The median age of affected dogs was 10 months (range five to 90 months). The most common presenting signs were cough (65 per cent), dyspnoea (43 per cent), haemorrhagic diathesis (35 per cent) and collapse (26 per cent). Four dogs were thrombocytopenic and eight had significant prolongations in prothrombin time and/or activated partial thromboplastin time. Thoracic radiographs were abnormal in 18 of 19 dogs. A variety of changes were observed, the most typical being a patchy alveolar-interstitial pattern affecting the dorsocaudal lung fields. Angiostrongylus vasorum larvae were found in seven of 10 bronchoalveolar lavage specimens and 19 of 19 faecal samples. Three dogs died shortly after admission to the hospital. The remainder were successfully treated with fenbendazole at a dose of 50 mg/kg for five to 21 days. A vasorum should now be considered endemic to south-east England. Angiostrongylus vasorum infection in 23 dogs (1999-2002) JOURNAL OF SMALL ANIMAL PRACTICE • VOL 45 • SEPTEMBER 2004 435 Department of Veterinary Clinical Sciences, The Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield, Hertfordshire AL9 7TA P. Chapman’s current address is Matthew J. Ryan Veterinary Hospital, University of Pennsylvania, 3900 Delancey Street, Philadelphia, PA 19104, USA