Biomedical subjects

B A Hopkins

Publications and source records attributed to B A Hopkins.

23 records · Page 2Linked to original sources

PubMedDate not supplied

High mortality of domestic turkeys associated with Ascaridia dissimilis.

Third- and fourth-stage Ascaridia dissimilis larvae were isolated from commercial white turkey intestinal scrapings from two farms that were experiencing high mortality. Lesions consisted of a necrotic-like enteritis that was most severe in the jejunum. Subsequent bacteriological isolation yielded heavy growth of Escherichia coli and Clostridium perfringens. The rate of mortality declined rapidly when the turkeys were administered 18 ppm fenbendazole for 7 days.

Animals↗

PubMedDate not supplied

Development of an enzyme-linked immunosorbent assay for Bordetella avium.

A Bordetella avium enzyme-linked immunosorbent assay (ELISA) was developed to detect serum antibodies in 1-day-old poults, experimentally infected turkeys, and naturally infected turkeys. The optimized procedure included use of a suspension of whole bacteria coated onto plastic microtiter plates, a 1:200 serum dilution, a 1:3200 dilution of commercially available goat anti-turkey IgG (heavy and light chain) conjugated with horseradish peroxidase, and 0.04% orthophenylenediamine as substrate. A sample/negative (S/N) ratio method of analysis was used to estimate antibody titer from absorbance values. The regression equation used to estimate antibody titers was derived from the testing of naturally infected turkey sera. The equation was derived by plotting the log10 titer of the sera against the S/N ratio at a 1:200 serum dilution. The ELISA was an effective method for detecting antibody to B. avium, and the procedure should prove useful for laboratories equipped for high-volume ELISA testing.

Animals↗

PubMedDate not supplied

Hemoglobinuric nephrosis in a rhea (Rhea americana).

An eighteen-month-old female rhea (Rhea americana) was presented dead for necropsy. The owner reported having observed blood in the droppings. Gross examination revealed a rhea in good body condition with a copious amount of frank blood in the cloaca. Large masses of matted fescue grass (Festuca spp.) distended the ventriculus and jejunum. No hemorrhage was evident in the digestive tract, which was otherwise void of ingesta. The kidneys were dark brown in color. Renal histopathology revealed a severe accumulation of eosinophilic pigment in the tubular epithelial cells of the proximal convoluted tubules, with tubular nephrosis and eosinophilic casts in the collecting tubules. It was concluded that the renal pigment was hemoglobin and not myoglobin, based on lack of evidence of muscle injury and the severe erythrophagocytosis evident in hepatic macrophages. The renal pigment also stained positive with the hemoglobin-specific Okajima stain. Hemoglobinuric nephrosis has not previously been reported in an avian species.

Animals↗

PubMedDate not supplied

Comparison of live avirulent PM-1 and CU fowl cholera vaccines in turkeys.

The live avirulent PM-1 Pasteurella multocida vaccine, grown in brain-heart infusion broth, was evaluated and compared in two experiments with the Clemson University (CU) vaccine, which had been shown to be effective in preventing fowl cholera in turkeys. Experiment 1 was performed during warm environmental temperatures and Expt. 2 during cooler environmental temperatures. The PM-1 vaccine was comparable with the CU vaccine in protecting turkeys against challenge with virulent P. multocida but was considered no less virulent than the CU because turkeys died after vaccination with both the PM-1 and the CU vaccines. A significantly (P < 0.05) higher percentage of unvaccinated turkeys challenged during the cooler environmental temperatures died than did unvaccinated turkeys challenged during the warmer temperatures. A microtiter agglutination test demonstrated a significant (P < 0.01) correlation between the level of serum anti-P. multocida antibody found 1 wk after vaccination and survival after challenge with virulent P. multocida in Expt. 1 and a significant (P < 0.05) correlation between these parameters in Expt. 2. However, there was a significant (P < 0.01) negative correlation between serum anti-P. multocida antibody titer 1 wk after vaccination and body weight gained 4 wk after vaccination, but before challenge, in Expt. 1, suggesting that vaccination with the live vaccines may have had a negative effect on body weight gain. At 4 wk after challenge or 8 wk after vaccination in Expt. 2, there was also a highly significant (P < 0.001) negative correlation between these parameters in the surviving turkeys.

Administration, Oral↗

PubMedDate not supplied

Differentiating turkey postvaccination isolants of Pasteurella multocida using arbitrarily primed polymerase chain reaction.

The chromosomal DNA of 29 field isolants of Pasteurella multocida from commercial turkey farms in Missouri and the avirulent Clemson University (CU) and M-9 vaccine strains of P. multocida were tested using the arbitrarily primed polymerase chain reaction (AP-PCR) in combination with 32P-labeled deoxycytidine triphosphate (dCTP) and high-resolution gel electrophoresis. The 29 field isolants of P. multocida were isolated from outbreaks of fowl cholera in turkey flocks in which vaccination with the CU vaccine had been performed within 2 weeks of the isolation, and it was suspected that the outbreak could have been due to the use of the live CU vaccine. The results of this study showed that: 1) the use of the live CU vaccine can lead to the isolation of the vaccine strain if the outbreak occurs within 2 weeks of vaccination; 2) a higher proportion of field isolants collected during 1983 and 1984, when the usage of the CU vaccine strain was highest on Missouri turkey farms, had PCR-amplified product profiles similar or identical to those of the CU vaccine strain compared with the period between 1987 and 1992, when its use was less; and 3) there was no relationship between the PCR-amplified product profiles and the serotype.

Animals↗