The explosive introduction of the snail Achatina fulica in Brazil illustrates the current concern with global changes favouring dissemination of infectious diseases. The mollusc is an important host for Angiostrongylus cantonensis, which occurs in Asia and the Pacific Islands and is a causative agent for eosinophilic meningoencephalitis. In the Americas there is another metastrongylid worm, An. costaricensis, that causes abdominal disease and may also be transmitted by Ac. fulica. Although both infections may occur in focal outbreaks and with low morbidity, very severe complicated clinical courses pose a challenge for diagnosis and treatment. Data on abdominal angiostrongyliasis are briefly reviewed.