Prevalence and diversity of gastrointestinal pathogens in native and invasive New Zealand lizards

The rainbow skink (Lampropholis delicata) is the only invasive reptile in New Zealand, and its role in disease ecology with native lizards is unknown. We investigated the prevalence and diversity of Salmonella species and Cryptosporidium species in native lizards and L. delicata. Fifty-five L. delicata and 355 native lizards of eight species were sampled from three locations in 2021. Salmonella was detected in 4.4% (95% confidence interval 2.6-7.4%) of native lizards and two serovars were identified. Cryptosporidium was detected in native lizards at a prevalence of 31.3% (CI, 26.2-37.0%) and included mostly C. parvum of five subtypes and a single sample of C. cuniculus. No pathogens were detected in L. delicata, even in locations where the species overlapped with native lizards carrying these pathogens. Native lizards were more likely to be carrying gastrointestinal pathogens in areas where L. delicata was present, suggesting their fitness may be decreased in these areas. We conclude that native lizards, particularly skinks, are wildlife reservoirs for gastrointestinal pathogens of zoonotic concern.