Zoonotic parasite carriage in the common brushtail possum

The presence of zoonotic parasites in free-range marsupials presents a risk for public health. Cryptosporidium, a parasite with zoonotic species, has been found in marsupials that are well adapted to urban settlement. The co-shared habitats of these marsupials with people facilitates an increased chance of Cryptosporidium being transmitted to humans. A meta-analysis of data from the Australian National Notifications database was performed to investigate the relationship between cryptosporidiosis notifications and population, age group and gender. The analyses indicated that cryptosporidiosis notifications have a proportional relationship with a population in each state and is highest in the 0~4 age group. In a laboratory component, faecal DNAs from brushtail possums were screened using PCR to yield 18S rDNA fragment (~830bp), and presumptive positive samples were sequenced to determine the types of Cryptosporidium present. Of 129 samples tested, seven samples (5.4%) were confirmed to be Cryptosporidium. Cryptosporidium parvum and C. hominis were each identified in a single sample, and the five remaining samples were a novel Cryptosporidium genotype. These findings support the hypothesis of marsupials as a vector of zoonotic parasites and also raise questions of public health risks posed by unknown Cryptosporidium types in urban-adapted wildlife.