Use of egg yolk in serological tests (ELISA and HI) to detect antibody to Newcastle disease, infectious bronchitis, and Mycoplasma gallisepticum.

Serum and yolks from commercial flocks and from hens exposed to Newcastle disease virus (NDV), infectious bronchitis virus (IBV), and Mycoplasma gallisepticum (MG) were tested for immunoglobulin G antibody by the enzyme-linked immunosorbent assay (ELISA) and the hemagglutination-inhibition (HI) test. Yolks prepared by chloroform extraction and low-speed centrifugation performed well in the serological tests used and were a suitable alternative to serum for antibody determination by the ELISA for NDV, IBV, and MG and by HI test for NDV.

Evidence of exposure of waterfowl and other aquatic birds to the hemagglutinating duck adenovirus identical to EDS-76 virus.

Serum and fecal samples from 12 species of aquatic birds were studied for evidence of exposure to a hemagglutinating duck adenovirus (DAV). DAV is serologically indistinguishable from egg-drop syndrome-76 virus. A total of 285 serum samples were tested by the hemagglutination-inhibition (HI) test. Forty-two percent of the birds had HI antibodies, with titers ranging from 8 to 256. Wild ducks showed the highest frequency of antibodies (56%) while in coots and grebes, antibody was less frequent, 33% and 26%, respectively. Attempted virus isolations from 79 fecal samples were unsuccessful. The data support the hypothesis that DAV is indigenous in wild duck populations and suggest that infection and viremia are limited in time and occur at a very early age.

The effect of incubation temperature on the propagation of duck adenovirus (virus 127-like) in duck and chicken cells.

Duck adenovirus (Cornell strain) was propagated in duck and chicken embryo cells at 37.5 C and at 40 C. In duck cells, virus levels, as indicated by HA titers, peaked earlier at 40 C than at 37.5 C. High titers were eventually observed in duck cells at both temperatures. In chicken embryo fibroblasts, no titers were observed at 37.5 C, whereas low titers were observed at 40 C. Evidence of virus propagation was not detected in chicken embryo liver and kidney cells.

Histopathological effects of diflubenzuron on the cirripede crustacean, Balanus eburneus.

Histopathological studies on the cirripede crustacean, Balanus eburneus, at light and electron microscopic levels indicated that the chitin-inhibiting insecticide, diflubenzuron, caused similar disruption of the exoskeleton as observed in insects. Under the light microscope, globular particles were present within the chitinous layers of the cuticle, and these particles appeared electron dense and pleomorphic at the ultrastructural level. The cytoplasm of the cuticle-secreting epidermal cells appeared more dense and showed at least a five-fold increase in multivesicular bodies, which possessed electron dense cores. Barnacles exposed to diflubenzuron for 10 days or longer at 750 and 1,000 ppb were delayed in the premolt phase of cuticle secretion.