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B C Easterday

Publications and source records attributed to B C Easterday.

At least 37 records · Page 2Linked to original sources
PubMed1980

Isolation of bovine herpesvirus-1 from trigeminal ganglia of clinically normal cattle.

Trigeminal ganglia collected from 56 adult dairy cattle at slaughter were maintained in explant culture. Bovine herpesvirus-1 was isolated from six ganglia after periods of 7 to 24 days' maintenance in vitro. Antibody against bovine herpesvirus-1, indicating exposure to that virus, was found in 45.4% of the sample population from which ganglia were collected.

Animals↗
PubMed1979

Hemagglutinin mutants of swine influenza virus differing in replication characteristics in their natural host.

In two mutant clones (L and H) of A/NJ/11/76 (Hsw 1N1) influenza viruses which differ slightly antigenically and markedly in replication characteristics in chicken embryos and Madin Darby canine kidney cells, these pleiotropic differences are mediated by mutation in the hemagglutinin gene (E. D. Kilbourne, Proc. Natl. Acad. Sci. U.S.A. 75:6258--6262, 1978). Experimental infection of swine with either the mutant L and H clones or recombinant viruses differing genetically only with respect to the presence of L or H hemagglutinin demonstrated greater infectivity for the natural host of viruses bearing the L hemagglutinin. Introduction of the L but not the H hemagglutinin gene into the human influenza virus A/PR/8/34 rendered it infective for swine. Both L and H variants were isolated from pigs naturally infected with contemporary swine influenza viruses when selective conditions for the suppression of the more prevalent L mutant were employed. The L and H mutants of swine influenza virus are yet another example of viral dimorphism in nature and probably are not mere artifacts of laboratory selection. In any event, the frequent apparent allelic appearance of the two forms suggests frequent mutation and/or reversion involving a point mutation in the hemagglutinin gene. The present studies demonstrate the importance of a single gene in the pathogenesis of an influenza viral infection in its natural host.

Animals↗
PubMed1979

A hitherto unreported paramyxovirus of turkeys.

A newly isolated avian virus is described which was obtained from a flock of laying turkey hens with respiratory disease and accompanying egg production drop. Characterisation of the virus indicated it to be of the paramyxovirus group and to be related through antigenic crossing with Newcastle disease virus. Examination of turkey sera from five separate flocks indicated natural infection with the paramyxovirus to be relatively widespread. Experimental infection of turkeys produced only mild respiratory disease.

Animals↗
PubMed1977

Isolation of type A influenza and Newcastle disease viruses from migratory waterfowl in the Mississippi flyway.

Twenty-seven chicken red blood cell agglutinating agents were isolated from 187 tracheal swabbings of apparently healthy migratory mallard ducks (Anas platyrhynchos) in the Mississippi flyway. Twenty-four of the isolants were type A influenza virus; 3 lentogenic Newcastle disease viruses were isolated. Isolations were not made from either 65 giant Canada geese (Branta canadensis) or 60 Franklins' gulls (Larus pipixcan).

Animals↗
PubMed1977

Strains of Hong Kong influenza virus in calves.

Three strains of Hong Kong influenza virus isolated from humans were compared with a strain isolated from a calf for their ability to cause disease in calves. One of the human strains. A/Aichi/2/68, was detected for five days in a calf, but all three failed to cause signs of disease. Strain A/cal/Duschanbe/55/71 could be detected for seven days and caused an influenza-like illness in calves.

Animals↗
PubMed1977

Infection and vaccination of pigs with influenza A/New Jersey/8/76 (Hsw1N1) virus.

Pigs were infected and had mild signs of illness when exposed to influenza A/New Jersey/8/76 (Hsw1N1) virus. Virus was recovered for up to eight days after exposure. The virus was readily transmitted to susceptible pen mates. Vaccination with inactivated whole-virus vaccine did not provide protection against infection or disease. There was some protection against challenge when the pigs were vaccinated with a temperature-sensitive strain of influenza A/New Jersey/8/76 virus.

Animals↗
PubMed1976

Evaluation of 6-azauridine and 5-iododeoxyuridine in the treatment of experimental viral infections.

The potential antiviral activity of 6-azauridine and 5-iododeoxyuridine was evaluated in a coordinated study at five institutions. Experimental models in five species, the mouse, rabbit, swine, cat, and ferret, were established with use of 10 viruses: Herpesvirus hominis types 1 and 2, murine cytomegalovirus, vaccinia virus, Shope fibroma virus, transmissible gastroenteritis virus, swine influenza virus, feline viral rhinotracheitis virus, feline panleukopenia virus, and ferret distemper virus. Criteria for selection were: (1) representation from a number of major groups of viruses, (2) reproduction of natural routes of infection, and (3) simulation of potentially treatable viral infections of man. Antiviral activity was observed for 5-iododeoxyuridine in H. hominis infections in hairless mice and influenza in swine, and a slight degree of efficacy was noted in rabbits infected with Shope fibroma virus. Toxicity was also observed in most of the experimental models. There was a suggestion of antiviral activity with 6-azauridine in swine infected with transmissible gastroenteritis virus; however, enhancement of disease and some toxicity were seen in most of the other models. Efficacy of these two compounds was not well substantiated by these studies.

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PubMed1975

Coronaviridae.

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Coronaviridae↗
PubMed1975

Antibody levels and immunity to infectious bovine rhinotracheitis virus (IBR) infections in Wisconsin dairy cattle.

Individual cows and calves in 7 Holstein-Friesian herds with a history of respiratory disease in Green County, Wisconsin, USA, were swabbed intranasally and bled monthly, some for periods over 1 year. Virus isolation and serological procedures were completed on the samples in an attempt to recognize the problems and peculiarities that IBR virus continues to cause in dairy cows, in spite of, and possibly because of vaccines available for immunization against this agent. While IBR virus was isolated from animals on 6/7 farms over the period of study the history of vaccination with Nasalgen IP prevented the differentiation of vaccine (avirulent) virus from field (virulent) virus. IBR virus was isolated from apparently healthy animals as well as animals having signs of respiratory disease. IBR virus was assumed to be the cause of recurrent respiratory disease and ocular disease on at least two of the farms studied as established by virus isolation, serology, and the presence of characteristic signs of respiratory disease. While IBR virus was present on the other five farms its precise role in the diseases observed was not determined. IBR virus, whether vaccine virus or field virus, appeared to be persistent in 6/7 of the herds studied. Keratoconjunctivitis and corneal ulceration were the only signs of disease in animals in one herd where the etiologic agent was presumed to be field strain IBR virus. Antibody to IBR virus did not protect animals from respiratory or ocular disease in which IBR virus was thought to be a causative agent. Adult animals that had antibody to IBR virus at the time of vaccination with Nasalgen IP generally did not respond after vaccination with an increase in IBR virus antibody. Those adults that did not have antibody prior to vaccination, generally responded to vaccination with a rise in antibody. Vaccination of calves with Nasalgen IP generally did not cause an increase in antibody. IBR virus antibody was higher in vaccinated herds with recurrent respiratory disease.

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