Pulmonary presentation of Dirofilaria immitis (canine heartworm) in man

Canine heartworm or Dirofilaria immitis can occasionally infect man. We present the case of a 36-year-old Balkan woman referred to us for a thoracoscopic biopsy of a well defined pulmonary mass. The latter was thoracoscopically resected and proved to be due to Dirofilaria immitis on histopathological examination. To our knowledge this is the second reported case in Western Australia, the first being that reported by Brine et al. The prevalence of the disease in Australia was recognized in 1969 in one study in the state of Queensland, where 12% of 761 dogs at one veterinary clinic and 20% of 296 dogs at another were shown to be infected. Dirofilaria immitis resides in the right ventricle and pulmonary arteries of dogs. The microfilariae are released into the blood stream and are transmitted to secondary hosts by mosquitoes.