Equine antibody to bovine serum induced by several equine vaccines as a source of extraneous precipitin lines in the agar gel immunodiffusion test for equine infectious anemia

Precipitin lines not associated with equine infectious anemia (EIA) were observed in routine agar gel immunodiffusion (AGID) testing for the infection. The serums which produced these lines were obtained from horses which had been given multiple vaccinations with commercially available cell culture-origin equine virus vaccines as part of a comprehensive herd health program. The lines formed against cell culture-derived, but not spleen-derived EIA viral antigens. Investigation revealed that bovine serum proteins in the vaccines induced precipitating antibodies which reacted with bovine serum proteins in cell culture-derived antigens. A vaccination trial, utilizing 4 commercially available vaccines in various combinations, indicated that as few as 2 vaccinations could induce AGID-detectable antibodies to bovine serum proteins in individual ponies. These antibodies were very transitory, usually lasting no longer than a week. Some horses, however, which had been given 4 vaccinations developed similar antibodies which persisted 3 months beyond the last vaccination. The extraneous precipitin lines produced by these antibodies in the AGID test for EIA were readily distinguished from true EIA-associated reactions and did not result in false-positive interpretations of the test. However, heavy percipitin lines due to strong antibovine serum activity did mask weakly positive EIA reactions.

Fatal generalized feline viral rhinotracheitis in a young adult cat

A 7-month-old cat died following a 17-day illness. Necropsy findings included sharply demarcated lingual ulcers and multifocal necrotic hepatitis. Intranuclear inclusions were found in the lesions, and a herpesvirus was recovered from specimens of liver and tongue. The virus was identified by neutralization with specific antiserum as feline rhinotracheitis virus.

Psittacine herpesvirus infection resembling pacheco's parrot disease

Herpesvirus was detected by electron microscopy in hepatocytes of psittacine birds that died at a Florida aviary. The virus was identified in hepatocytes of chick embryos and budgerigars that were given injections of liver suspensions from naturally infected psittacines. Infected hepatocytes had prominent intranuclear inclusions that contained naked nucleocapsids. Both naked and enveloped virions were seen in the cytoplasm of hepatocytes, and enveloped nucleocapsids occasionally were seen in the perinuclear cisternae and extracellularly. The experimental and spontaneous disease mimicked a condition in parrots described previously by Pacheco. The viral agent was classified as Herpesvirus on the bases of the character of the intranuclear inclusions, the size and conformation of the agent as determined by electron microscopy and filtration, and the sensitivity of the agent to ether.