The prevalence of psittacine circovirus in native and exotic parrots in New Zealand : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Conservation Biology at Massey University
Psittacine circovirus (PCV) has been identified in more than 60 psittacine species worldwide in both aviary and wild populations. The virus is a causative agent of psittacine circoviral disease (PCD), a highly infectious disease characterised by beak and feather dystrophy, high juvenile mortality or long-term immunological suppression. The virus is known to be very difficult to control or eradicate and among wild Australian parrots, the prevalence of infection is 10-20 %. No information on the incidence of PCV in parrots in New Zealand was available. The aims of this study were 1) to determine the prevalence of PCV in wild exotic parrots, 2) to determine the prevalence of PCV in wild native parrots, 3) to identify the incidence of PCV in captive native parrots, and 4) to suggest recommendations for the future conservation management of native parrots populations in New Zealand. Two species of exotic parrots; eastern rosella and sulphur-crested cockatoo, and four species of native parrots; kakapo, kaka, kea and parakeet were examined. Feathers of these parrots were collected from different regions in New Zealand and PCR assay was conducted to identify the presence of PCV. The prevalence of PCV in wild exotic parrots in New Zealand was considerably high in both species of exotic parrots, as the prevalence of PCV at the 95% confidence intervals ranged from 19.17 - 44.02% in eastern rosellas and 22.04 - 33.07% in sulphur-crested cockatoos. No wild native parrots showed any evidence of PCV in PCR assay and given the sample sizes in this study, the prevalence of PCV was estimated as less than 4-7% if PCV is present in the populations. However, the first isolation of PCV in native parrots occurred in two species of parakeets in captivity; red-crowned parakeets and Antipodes Island parakeets. No significant abnormalities were detectable in the red-crowned parakeets but the Antipodes Island parakeet died shortly after translocation. The presence of PCV was confirmed in contact birds in both cases.