Angiostrongylus is a parasitic nematode that can cause severe gastrointestinal or central nervous system disease in humans, depending on the species. Angiostrongylus cantonensis, which is also known as the rat lungworm, causes eosinophilic meningitis and is prevalent in Southeast Asia and tropical Pacific islands. The recognized distribution of the parasite has been increasing over time and infections have been identified in other areas, including Africa, the Caribbean, and the United States. Angiostrongylus costaricensis causes eosinophilic gastroenteritis and is found in Latin America and the Caribbean.

Image: Left: Angiostrongylus cantonensis third stage (L3), infective larva recovered from a slug. Image captured under differential interference contrast (DIC) microscopy. Right: Angiostrongylus adult worm recovered from vitreous humor of a human patient. The bursa is one indication that this is a male worm. The worm is most likely A. cantonensis based on the patient's geographic location. Credit: DPDx