Search

Plaque-purified and non-plaque-purified velogenic viscerotropic Newcastle disease viruses (VVNDVs) were inoculated into golden-mantled rosellas (Platycercus eximius). VVNDV produced acute clinical disease in this species: all birds died within 6 days postexposure. There was no difference between the two inoculation groups in clinical signs. Seven tissues and five tissue swabs were collected from each of 15 birds. The VVNDV concentration in each specimen was titrated, and the concentrations were compared. The lung and trachea had the highest concentrations of virus in both the tissue suspensions and the swab suspensions. The average virus concentrations of the lung were 10(5.9) 50% embryo lethal doses (ELD50) per 0.1 ml for the tissue suspension and 10(4.9) for the swab. The average virus concentrations of the trachea were 10(5.6) ELD50 per 0.1 ml of tissue suspension and 10(4.6) for the swab.

The feces of 125 psittacine birds, representing 12 species, were cultured on selective media to determine the presence of Escherichia coli. Only 13.6% (17) of the birds yielded E. coli.

A virus suspected of causing high death rates in fledgling budgerigars in Georgia and Texas aviaries was isolated in budgerigar embryo fibroblasts inoculated with tissue homogenates from affected birds. Virus was most easily recovered from tissues containing many intranuclear inclusion bodies. Cytopathic effect on fibroblasts of all four isolates was characterized by a swollen nucleus followed by rounding and detachment of the affected cell from the monolayer. Properties suggesting the B-931 isolate belongs to the papovaviridae family are (1) presence of DNA; (2) insensitivity to treatment with CHCl3; and (3) presence of cubic viral particles 42 to 49 nm in diameter in the nucleus of infected chicken embryo fibroblasts. The isolate did not hemagglutinate erythrocytes of chickens, turkeys, budgerigars, guinea pigs, or type O humans and was basically stable against heating and freeze-thawing. An examination of fledgling budgerigars from infected aviaries demonstrated that sick birds carried more virus than healthy birds.

An upper respiratory condition that resulted in 20% mortality in a flock of yellow-naped Amazon parrots was apparently caused by a concomitant infection of mycoplasmas and bacteria. Mycoplasma gallisepticum (MG), M. iowae, and an unidentified mycoplasma were isolated from the affected parrots. Budgerigars were experimentally infected with a parrot strain of MG designated MG(P) 1669 as well as with the R strain of MG and the F10-2 strain of M. synoviae (MS). Air-sac lesions were evident in all groups of challenged budgerigars, and MS and MG were cultured from the tracheas, air sacs, and lungs of the budgerigars up to 5 weeks postexposure. Serological findings were ambiguous and therefore considered unreliable. White leghorn and commercial broiler chickens challenged with the MG(P) 1669 isolate did not exhibit any significant air-sac lesions relative to the controls. However, MG was cultured from both groups of experimentally infected birds. Eight weeks after exposure, the white leghorns were seropositive to all MG antigens used in the agglutination test.

Pacheco's disease herpesvirus was determined to be the agent responsible for the death of about 200 psittacine birds comprising five species. Clinical signs, necropsy lesions, and virus isolation and identification methods are described.