The effects of Toxoplasma gondii on New Zealand wildlife: implications for conservation and management

Toxoplasma gondii is a globally widespread protozoan parasite that can infect all bird and mammal species. Cat species (Felidae) arc the only known defmitive host for T. gondii and this parasite should have been absent from New Zealand prior to the introduction of the domestic cat (Felis catus) in the 18th Century. Clinical toxoplasmosis has recently been reported in multiple wild-living New Zealand native species, including: Hector's and Maui dolphins (Cephalorhynchus hectori hectori and Cephalorhynchus hectori maul, respectively), kaka (Nestor meridionalis), red-crowned kakariki (Cyanoramphus novaezelandiae), kerera (Ifemiphaga novaeseelandiae) and several kiwi species (Apteryx spp.). However, the prevalence of T. gondii infection and associated disease are unknown for most New Zealand native species, and the wider conservation risks of T. gondii remain poorly understood. The preliminary evidence suggests that fatal toxoplasmosis may be more frequent in Hector's and Maui dolphins relative to other native cetaceans and avifauna that have been assessed for infection. This review summarises the research on the effects of T. gondii on New Zealand wildlife, identifies potential options for managing conservation risks, and outlines critical knowledge gaps.