Rainfall- and Temperature-Driven Emergence of Neural Angiostrongyliasis in Eastern Australia, 2020-2024.

Neural angiostrongyliasis (NA), caused by rat lungworm (Angiostrongylus cantonensis), is an emerging zoonotic disease on Australia's east coast. The number of cases has risen since 2010. This study investigated the diagnosis, genetic diversity of A cantonensis, and spatial and temporal dynamics of canine NA (CNA). We analyzed cerebrospinal fluid samples from 180 clinically suspected cases (2020-2024) using AcanR3990 quantitative polymerase chain reaction, confirming infection in 93. Cases were detected around Brisbane and Sydney, with peak occurrence in 2022 (32 cases). Generalized linear modeling demonstrated that CNA occurrence depends on immediate and long-term rainfall (1- and 10- to 12-month lags) and medium-term temperature changes (5- to 7-month lags). Partial cox1 sequencing revealed Ac13 as the dominant haplotype (9/15). Comparison with an established enzyme-linked immunosorbent assay using 50 randomly selected samples showed substantial agreement (κ = 0.66). With many cases likely remaining undiagnosed, NA poses an ongoing One Health issue in Australia.