G. M. Cross

The haemagglutination spectrum of psittacine beak and feather disease virus

A simple method for concentrating psittacine beak and feather disease virus (PBFDV) from crude feather suspensions is described. The addition of 10% polyethylene glycol (MW 6000 to 9000) to feather suspensions facilitated the precipitation and pelleting of PBFDV by low speed centrifugation. Pellets were resuspended in one-twentieth of the original volume with caesium chloride (CsCl) buffer and subjected to isopycnic ultracentrifugation. Peak haemagglutination activity (HA) occurred at 1.35 g/ml in PBFDV CsCl gradients. CsCl purified virus agglutinated galah (Eolophus roseicapillus), eastern long-billed corella (Cacatua tenuirostris), sulphur-crested cockatoo (Cacatua galerita), Major Mitchells cockatoo (Cacatua lead-beateri) and gang gang cockatoo (Callocephalon fimbriatum) erythrocytes, but not those of 19 other avian or five mammalian species. PBFDV agglutinated galah erythrocytes at 4 degrees C and 37 degrees C over a wide range of pH and no change in HA titre was observed when PBFDV was treated with chloroform. HA persisted in PBFDV suspensions heated to 80 degrees C for 30 min, but was not detected after incubation at higher temperatures. High HA titres were detected in the feathers, serum, liver and kidneys of PBFD-affected birds.

A serologic survey for avian polyomavirus and Pacheco's disease virus in Australian cockatoos.

Sera collected from wild and captive Australian cockatoos and other psittacine species (n = 411) were tested for antibodies to avian polyomavirus (APV) and Pachecos disease virus (PDV). Of 144 wild sulphur-crested cockatoos (Cacatua galerita) sampled at three regions in New South Wales (NSW) 96 (64.4%) birds had positive (>/= 1:32) neutralizing antibody titres to avian polyomavirus (range 1:32-1:2048). Two of 17 wild long-billed corellas (Cacatua tenuirostris) were also APV-antibody positive. However, no samples from 107 wild galahs (Eolophus roseicapillus) were positive for neutralizing antibody to APV. Sera were also collected from captive psittacine bird flocks from NSW, Tasmania, Victoria, and Western Australia. In a mixed aviary of cockatoos and lorikeets, APV antibody was detected in sera from sulphur-crested cockatoos, Major Mitchells cockatoos (Cacatua leadbeateri), a white-tailed black cockatoo (Calyptorhynchus baudinii latirostris), a red-tailed black cockatoo (Calyptorhynchus magnificus) a single galah, a rainbow lorikeet (Trichoglossus haematodus), and a scaley-breasted lorikeet (Trichoglossus chlorolepidotus). All 411 wild and captive birds were negative for the presence of neutralizing antibody to PDV. These results indicate that wild sulphur-crested cockatoos in NSW are enzootically infected with avian polyomavirus and that the sampled populations are free of Pachecos disease.