Older Urban Rats Are Infected with the Zoonotic Nematode

Rats, being synanthropic, are hosts to agents of zoonotic diseases that pose a threat to human and domestic animal health. The nematode parasite , commonly known as the rat lungworm, is no exception; it can cause potentially fatal neural disease in humans, dogs and other species. The distribution of (haplotypes SYD.1 and Ac13) and its close relative, is not well understood in Australia. We investigated the prevalence of in rats in Sydney, Australia, primarily faecal qPCR, and identified the species and haplotypes using partial 1 sequencing. We found a moderate prevalence of infection (29%; 95% CI: 16.1-46.6%) in black () and brown () rats around public parks and residential areas. This study demonstrates that Sydney's urban rat population is a reservoir for . Modelling infection status as a function of rat species, sex, tibia length (as a proxy for age), and health index (a measure of weight by size) revealed that older rats are statistically more likely to be infected (  = 5.331,  = 0.021). We observed a dominant presence of the SYD.1 haplotype, for which the implications are not yet known. No was detected, leading us to suspect it may have a more restricted host- and geographical range. Overall, this study illustrates the presence and potential risk of infection in Sydney. Public education regarding transmission routes and preventative measures is crucial to safeguard human and animal health.