Neuroangiostrongyliasis: accidental zoonosis caused by the rat lungworm

The genus Angiostrongylus comprises parasitic nematodes that primarily infect the respiratory and circulatory systems of vertebrates, posing significant medical and veterinary concerns. The life cycle involves an indirect transmission between definitive and intermediate mollusc hosts, such as slugs or snails. Three species, A. cantonensis, A. mackerrasae and A. malaysiensis, are notable for their migration into the central nervous system (CNS) of their definitive rat hosts. Angiostrongylus cantonensis is particularly concerning, because it initiates CNS migration in various vertebrates, including accidental hosts like humans and dogs, leading to parasitic meningitis called neuroangiostrongyliasis (NAS). Angiostrongylus cantonensis, first identified in China and causing eosinophilic meningitis in humans and dogs, has expanded globally. Transmission to accidental hosts often occurs through ingestion of raw or undercooked snails, contaminated produce or water. Human cases in eastern Australia are rare but can be severe, whereas canine cases are more frequent. Diagnostic challenges persist, with advanced imaging and serological tests offering limited utility. Recent developments in hypersensitive quantitative polymerase chain reaction (qPCR) assays show promise for improved detection. Understanding the transmission dynamics and enhancing diagnostic capabilities are crucial for managing this zoonotic threat.