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Biomedical subjects

G A Erickson

Publications and source records attributed to G A Erickson.

35 records · Page 2Linked to original sources
PubMed1986

Survey of selected diseases in wild swine in Texas.

Tissue, fecal, and serum specimens and swabs of nasal turbinates and tracheas were collected from 100 wild swine (Sus scrofa) from 10 populations in Texas and, along with 24 additional serum specimens, were evaluated for selected swine diseases. Swine positive for pseudorabies were detected in 7 populations. Brucella suis biovar 1 was isolated from 4 swine from 2 populations, but positive serologic results may indicate a more widespread distribution of the organism. All populations contained swine that were positive for leptospirosis. Trichinella spiralis was not found in the swine evaluated.

Animals↗
PubMed1986

Antibodies to vesicular stomatitis virus in populations of feral swine in the United States.

From 1979 to 1985, 941 feral swine (Sus scrofa) from 53 locations in 15 states were serologically tested for antibodies to vesicular stomatitis virus (VSV). Antibodies to New Jersey serotype VSV were present in 75 swine from five locations in Arkansas, Florida, Georgia, and Louisiana. Within these populations, antibody prevalences ranged from 10 to 100%. No antibodies to Indiana serotype were detected.

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PubMed1985

Enzootic vesicular stomatitis New Jersey type in an insular feral swine population.

Free-ranging feral swine from Ossabaw Island, Chatham County, Georgia, were serially bled and tested for vesicular stomatitis New Jersey type serum neutralizing antibody to determine the intensity and progression of annual vesicular stomatitis activity. From November 21, 1981 to October 11, 1982, and from March 15, 1983 to October 14, 1983, 307 and 340 swine were sampled, respectively. Seroconversions were initially detected during the first week of June and continued into September in both 1982 and 1983. Serologic results indicate a seroconversion incidence during 1982 and 1983 of approximately 12% and 60%, respectively. Similar patterns in timing and affected geographic area were observed during both years, with the earliest viral activity and highest incidence restricted to the southern portion of the island. Clinical vesicular stomatitis was not seen during 1982. However, during 1983, vesicular stomatitis New Jersey type virus was isolated from vesicular lesions on two swine.

Animals↗
PubMed1984

Comparison of a modified counterimmunoelectrophoresis test and a microimmunodiffusion test for detection of pseudorabies virus antibodies in porcine sera.

The correlation of a modified counterimmunoelectrophoresis (CIE) test and a microimmunodiffusion test for detecting pseudorabies virus antibodies in porcine sera was investigated, using as reference a standard virus neutralization test. The counterimmunoelectrophoresis test exhibited a sensitivity comparable to the microimmunodiffusion test but was not as sensitive as the virus neutralization test. The best feature of the modified counterimmunoelectrophoresis test is that it is a rapid test. It provides an alternative to currently used diagnostic tests for detection of pseudorabies virus antibodies in sera from field reared and experimentally reared swine exposed to pseudorabies virus.

Animals↗
PubMed1978

Epizootiologic aspects of viscerotropic velogenic Newcastle disease in six pet bird species.

Pet birds of 6 species were exposed to a psittacine isolate to viscerotropic velogenic Newcastle disease (VVND) virus to evaluate the impact of VVND in those species. Species examined were the budgerigar, yellow-headed Amazon parrot, canary, halfmoon conure, lesser hill mynah, and blackheaded nun. Five of the 6 species were highly susceptible to infection with VVND virus. Canaries were relatively refractory to infection with the virus. Contact birds of the same species developed infections almost as rapidly as did the birds directly exposed to nebulized VVND virus. Mortality was most marked for the conures. Less than half of the parrots exposed to nebulized virus died of VVND. Of the directly exposed budgerigars, mynahs, and nuns, 16% to 22% died during an observation period of postexposure days 0 through 28.

Animals↗
PubMed1976

Ultrastructural characterization and hepatic pathogenesis of duck plague virus.

Six-week-old white Pekin ducks were inoculated intravenously with duck plague virus (DPV) isolated from wild waterfowl. The virus replicated in hepatic macrophages, hepatocytes, and bile duct epithelium. In ultrathin sections, herpes-like nucleocapsids and virions were found respectively in the nucleus and cytoplasm of infected cells. Typical herpesviral capsids and virions were seen in negatively-stained preparations of duck embryo fibroblasts. Antibodies against Holland-attenuated strain of DPV reacted with virions of this isolate.

Animals↗
PubMed1975

Rapid diagnosis of Venezuelan equine encephalomyelitis by fluorescence microscopy.

Goat Venezuelan equine encephalomyelitis (VEE) antiserum and normal serum were conjugated and evaluated for staining sensitivity and specificity. Cross-staining with either eastern or western equine encephalomyelitis virus-infected cells did not occur. The baby hamster kidney (BHK-21) cell line when combined with highly specific VEE conjugate detected 100 medium suckling mouse intracerebral lethal doses (suckling mouse LD-50/IC) of the 1B subtype of VEE virus per milliliter of equine tissue suspension. Conjugated goat antiserum was assayed for sensitivity for detection of VEE virus-infected equine serums and tissue suspensions. The BHK-21 cell line was superior to either primary duck embryo fibroblast (DEF) cells or African green monkey kidney (Vero) cells for propagating the GJ9-1BJ subtype of VEE virus.

Animals↗
PubMedDate not supplied

Interactions between viscerotropic velogenic Newcastle diseases virus and pet birds of six species. I. Clinical and serologic responses, and viral excretion.

Clinical and serologic responses to a psittacine isolate of viscerotropic velogenic Newcastle disease virus (VVNDV) were evaluated in pet birds of six species: budgerigar, yellow-headed Amazon parrot, halfmoon conure, lesser hill mynah, black-headed nun, canary. The clinical response was most marked in the budgerigars, parrots, and conures, and only minimal in the nuns. Between post-exposure days (PED) 3 and 5 some birds developed ruffled plumage, conjunctivitis, and central nervous system dysfunction: ataxia, wing tremors, paralysis of the extremities, and tremors of the head accompanied by nodding and jerking. Mortality by PED 203 was 55% (29/52) in the halfmoon conures, 22% (23/105) in budgerigars, 29% (12/42) in parrots, and 21% (15/71) in nuns. The only clinical signs in canaries and mynahs were progressive death losses, respectively 25% (33/132) and 21% (10/48). The visceral lesions common in chickens with VVNDV were not observed in these six species. Canaries rapidly eliminated Newcastle disease virus (NDV), whereas it was detected for protracted periods in the oral and cloacal secretions of the other five species (for more than a year in parrots). Serologic evaluation by the hemagglutination-inhibition and neutralization tests also indicated prolonged NDV infections in 5 of the 6 species. The seroconversion rate observed in canaries was minimal (13%).

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PubMedDate not supplied

Interactions between viscerotropic velogenic Newcastle disease virus and pet birds of six species. II. Viral evolution through bird passage.

Following in vivo studies in pet birds of 6 species, 279 Newcastle disease virus (NDV) reisolates were selected for characterization by the embryonated-chicken-egg mean-death-time, plaque-assay, hemagglutination-elution, and hemagglutinin-thermostability techniques. Initially, the 279 isolates were screened by the mean-death-time and plaque-assay techniques, and 5 sequential isolates were chosen for each of 3 budgerigars and 2 parrots for characterization by the other 2 in vitro assays to determine whether the Colorado Psittacine Isolate of viscerotropic velogenic (VV) NDV (COPI-VVNDV) had evolved during passage through pet birds. Nineteen isolates were then selected for chicken back-passage studies. Fifteen of the 19 isolates were chosen for potential avirulence for 8-week-old domestic chickens. The 4 remaining isolates produced large red plaques when assayed and were therefore used as virulent virus controls likely to be VVNDV. Subsequent in vitro characterization of selected back-passage chicken NDV isolates demonstrated little change in the 4 parameters originally evaluated for the pet-bird isolates used for the back-passage studies. Although the psittacine isolate slowly evolved to relatively avirulent strains of NDV by passage in pet birds, reversion did not occur during the chicken back-passage studies.

Animals↗
PubMedDate not supplied

Embryonated eggs compared with fragments of chorioallantois attached to egg shell for isolation of Newcastle disease virus.

The feasibility of using fragments of chorioallantois attached to egg shell (C-S) as an alternative to embryonated eggs for isolating Newcastle disease virus (NDV) was assessed. In paired titrations of 6 strains of virus, embryonated eggs detected an average of 6-to-7-fold greater amounts of virus than did C-S fragments. The efficiency of isolation of viscerotropic velogenic NDV from 240 swab samples was 97% in embryonated eggs and 84% in C-S fragments. Sensitivity differences between the 2 host systems were revealed only in tests of samples expected to contain small amounts of virus. These results suggest that C-S fragments can be reliably used in some but not all instances, thereby relieving logistic constraints sometimes associated with the use of embryonated eggs.

Allantois↗