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M S Hofstad

Publications and source records attributed to M S Hofstad.

33 records · Page 2Linked to original sources
PubMedDate not supplied

Antibiotic aerosolization: the effect on experimentally induced Alcaligenes rhinotracheitis in turkeys.

Oxytetracycline hydrochloride was delivered by aerosol twice daily for 3 days to uninfected turkeys and to turkeys experimentally inoculated with Alcaligenes faecalis. The clinical, microbiological, and histological changes in the upper respiratory tracts were studied. No lesions were observed in the tracheas of uninoculated poults exposed to the aerosol. In experimentally infected poults, clinical signs included ocular and nasal discharges and open-mouthed breathing. Histologic lesions included progressive bacterial colonization of ciliated epithelium, loss of cilia, depletion of mucin from goblet cells, and accumulation of inflammatory cells within the tracheal lumen. Aerosolization of oxytetracycline effected a temporary decrease in bacterial colonization and a delay in clinical signs and histologic lesions in infected treated poults compared with untreated infected poults. Bacterial colonization and histologic lesions in the tracheas of both treated and untreated infected poults were similar by 4 days after the treatment was discontinued. This study indicates additional research with bactericidal antibiotics is needed to further evaluate antibiotic aerosolization as a treatment for alcaligenes rhinotracheitis.

Aerosols↗
PubMedDate not supplied

Immune response of poults following intranasal inoculation with Artvax vaccine and a formalin-inactivated Bordetella avium bacterin.

Poults 3 weeks and older developed temporary tracheal resistance to intranasal challenge following inoculation of either Artvax vaccine or formalin-inactivated Bordetella avium bacterin by the intranasal and eyedrop routes. Resistance usually persisted for 3-4 weeks after B. avium challenge. However, with constant exposure to infected controls, the vaccinated birds eventually developed tracheal infection. Day-old poults did not respond to either the Artvax or the bacterin and were completely susceptible to challenge. Two-week-old poults responded to some degree, but poults 3 weeks old and older responded best. Poults inoculated with bacterin by aerosol or by drinking water did not respond as well as those inoculated by the intranasal and eyedrop routes. When poults were given a single subcutaneous injection at 3 weeks of age and challenged 2 weeks later, three of five resisted infection for 18 days.

Alcaligenes↗
PubMedDate not supplied

Prevention of egg transmission of Mycoplasma meleagridis by antibiotic treatment of naturally and experimentally infected turkey eggs.

Turkey eggs infected naturally and experimentally and treated with 1 mg of tylosin or gentamicin before incubation produced progeny with less infection with Mycoplasma meleagridis than did infected but untreated eggs. Higher doses of gentamicin eliminated infection, as indicated by an absence of M. meleagridis antibodies in poults tested at 3 weeks and retested at 5 weeks of age. The rate of reduction or elimination of egg transmission was correlated negatively with the incidence of M. meleagridis infection in untreated controls. Hatchability was reduced by gentamicin, especially at doses of 1.75 and 2 mg, whereas tylosin at 1 mg/egg improved hatchability.

Animals↗
PubMedDate not supplied

Cross-immunity in chickens using seven isolates of avian infectious bronchitis virus.

Groups of 75 chickens were each infected with one of 7 isolates of infectious bronchitis virus (Mass 41, Holland 52, SE 17, Ark 99, Clark 333, JMK, and Florida). Following recovery, they were challenged along with susceptible controls to the homologous and 6 heterologous isolates. Cross-immunity was determined by virus recovery 4 or 5 days post-challenge. Challenge with the homologous isolate resulted in 90-100% protection. Challenge with heterologous isolates gave variable results and an overall average resistance of 38%. The SE-17-recovered chickens had a 50% protection, whereas the Holland-52-recovered chickens ahd a 13.3% protection.

Animals↗
PubMedDate not supplied

Susceptibility of turkey poults from vaccinated and unvaccinated hens to alcaligenes rhinotracheitis (turkey coryza).

One specific-pathogen-free breeder flock of Beltsville small white turkeys was given two doses of oil-emulsion-adjuvanted Alcaligenes faecalis bacterin 3 months apart, and another flock was left unvaccinated. Progeny from each flock from eggs laid after both first and second vaccination were exposed to the homologous strain (838) of A. faecalis at 1 day of age either experimentally (10(7) colony-forming units intranasally) or naturally (continuous contact with an infected poult) and monitored for 2, 4, or 6 weeks. Progeny from vaccinated hens had substantial resistance to alcaligenes rhinotracheitis compared with progeny from unvaccinated hens; resistance was greatest in progeny from twice-vaccinated hens. Poults from vaccinated hens had improved livability and growth, delayed onset of infection and clinical signs, and a less severe disease process. The results of this study indicate that breeder hen vaccination could be a useful method for providing poults with early protection against alcaligenes rhinotracheitis.

Alcaligenes↗