Rat lungworm, Cryptosporidium and other zoonotic pathogens of Rattus rattus and native wildlife on Sydney's Northern beaches

Urbanisation is disrupting natural habitats and potentially causing spillover of zoonotic diseases from animals common in highly populated areas to natural environments and native wildlife. The black rat (Rattus rattus) is a common commensal species abundant in urban areas and nearby bushland in Australia and globally. It can be a major reservoir of pathogens and vectors for diseases that affect humans, pets, and wildlife. We examined pathogen prevalence in black rats and native wildlife in peri-urban northern Sydney. We trapped rats and native wildlife at eight 1-ha bushland sites and sampled for a range of internal pathogens from necropsied individuals (n=85 rats) and animal/trap swabs (n=54 native individuals). We detected a high prevalence of rat lungworm (Angiostrongylus spp.) in black rats (67%) as well as native wildlife including long-nosed bandicoots (Perameles nasuta; 43%; previously undetected) and bush rats (R. fuscipes; 33%). Incidence of detection tended to be more frequent where rat activity was greatest. Non-zoonotic Cryptosporidium spp. was also recorded in 17% of black rats and Salmonella spp. in 21% of bandicoots. Our findings suggest black rats may be facilitating spill-over of disease into native wildlife. The detected prevalence of Angiostrongylus spp. suggests an increasing occurrence in this natural system. These data provide valuable insight for disease management highlighting important reservoirs of disease which could be targeted to reduce disease burden in humans, pets, and wildlife.