Studies on Austrobilharzia terrigalensis (Trematoda: Schistosomatidae) in the Swan Estuary, Western Australia: infection in the definitive host, Larus novaehollandiae

The prevalence of Austrobilharzia terrigalensis infection in the Silver Gull (Larus novaehollandiae) population of the Swan Estuary, Western Australia was shown from autopsies to be 80.7% with a median worm load of five pairs. Maximum egg-output was recorded about 3 weeks after the first eggs were voided in the faeces of experimentally-infected birds. Few worms were thought to live longer than 2–3 months. Egg-output from naturally infected L. novaehollandiae was generally low, with a median rate of 24 eggs/g for birds living within 125 km radius of Perth. The liver, duodenum and small intestine were the organs most heavily involved in A. terrigalensis infection.