Distribution of Angiostrongylus cantonensis in Papua New Guinea.

Examination of 97 rats trapped in Port Moresby and Lae on the mainland of Papua New Guinea and in Rabaul, East New Britain Province, showed that 12.4% were infected by Angiostrongylus cantonensis. Larval An. cantonensis were found in Achatina fulica snails collected at these towns, from the Ramu Valley near Madang on the mainland and at locations in West New Britain, New Ireland and Bougainville Island. The mollusc infection rates ranged from 12.7% at Port Moresby to 32.4% at Kimbe in West New Britain (mean: 19.2%). Larvae obtained from snails from Port Moresby, Lae, the Ramu Valley and Rabaul were fed to laboratory rats and mature nematodes obtained subsequently provided confirmation that the species was An. cantonensis. Ach. fulica has not yet colonized the Highland region of Papua New Guinea and rats trapped in Goroka were free of infection. Human angiostrongyliasis has now been reported from Rabaul and studies have shown a high level of immunological responsiveness to the parasite in the sera of residents of East New Britain.