Two cases of neuroangiostrongyliasis: A rare disease because rarely considered or rarely diagnosed?

Aim: The rat lungworm, Angiostrongylus cantonensis, is well established in eastern Australia, where it is the almost exclusive cause of human eosinophilic meningoencephalitis (EME). While neuroangiostrongyliasis can result in severe morbidity or death, its diagnosis requires a high index of clinical suspicion among medical practitioners. Prevention requires a high level of public awareness.

Methods: We report two cases of EME in children from Queensland and summarise all reported Australian cases from the literature. We discuss the pathogenesis of neuroangiostrongyliasis, with particular reference to the timing of prophylaxis and treatment.

Results: A 5-year-old girl developed severe headache, eosinophilic meningitis and abnormal neuroimaging following a holiday to Bali. A 10-year-old boy with Rubinstein-Taybi syndrome, marked developmental delay and pica developed EME following ingestion of a snail, resulting in long-term morbidity. From 1971 to 2018, 28 Australian cases have been reported, with acquisition restricted to Southeast Queensland and New South Wales. Ages ranged from 10 months to 45 years; most were male and most likely acquired infection from consuming unwashed lettuce or vegetables. The mortality rate was 18%; most fatalities occurred in children <1 year old. Long-term neurological deficit was reported in 14% of cases and a full recovery in 57% of cases.

Conclusions: Heightened medical and public awareness of the parasite is required to prevent infection and subsequent disease. A better understanding of the efficacy of prophylactic anthelmintic following ingestion or handling of molluscs and further studies of epidemiology of this parasite will inform and facilitate public health recommendations.