Psittacine beak and feather disease (PBFD) is a highly contagious viral disease recognised as a key threatening process to endangered psittacine birds in Australia. Management of this threat is problematic because PBFD is endemic in many populations of abundant native psittacines, resulting in a continual risk of spillover into threatened populations. The recent emergence of PBFD in forest red-tailed black cockatoos (Calyptorhynchus banksii naso), a threatened species endemic to south-west Western Australia, is a conservation concern because its effect at a population level is uncertain.
In 2013, PBFD was confirmed by PCR, haemagglutination (HA) and haemagglutination inhibition (HI) assays in two juvenile forest red-tailed black cockatoos with clinical signs of chronic PBFD. The affected birds originated in the wild, but had been captive for eight months at separate rehabilitation centres prior to diagnosis. Subsequent screening of all in-contact birds, including 21 forest red-tailed black cockatoos and 6 Carnaby’s cockatoos (Calyptorhynchus latirostris), found no evidence of active infection or seroconversion, despite prolonged close contact with the infected birds.
A research project investigating PBFD prevalence in wild forest red-tailed black cockatoos commenced in July 2013. Cockatoos entering the rehabilitation program due to illness or injury were selected as the study population, and screened for PBFD at a commercial laboratory by PCR, HA and HI assays. Preliminary results of this research found a prevalence of 0% (n=112, 95% CI:0-3.3%).
While forest red-tailed black cockatoos are susceptible to PBFD, these results indicate that the disease currently occurs at a very low prevalence in the wild population. Of note is the absence of infection in cockatoos exposed to high viral loads for an extended period, which suggests that forest red-tailed black cockatoos and Carnaby’s cockatoos are relatively resistant to infection with PBFD virus.