title: Field evaluation of the safety and efficacy of a temperature-sensitive Mycoplasma synoviae live vaccine.
abstract: Mycoplasma synoviae (MS) strain MS-H was used in three separate commercial flocks for large-scale evaluation of the safety and efficacy of the vaccine under commercial conditions. MS-H successfully colonized meat and layer-breeders vaccinated by eyedrop and persisted for up to 55 wk after vaccination. Restriction fragment length polymorphism analysis showed that MS-H was the only strain isolated from two vaccinated flocks. In a third flock, challenge with a wild-type MS occurred, and this strain was isolated from both vaccinated and unvaccinated birds. Vertical transmission of MS-H was investigated by culturing pipped embryos and testing broiler progeny for MS antibody at processing (56 days old). No evidence of vertical transmission was detected. Lateral transmission of MS-H strain from vaccinated to unvaccinated birds occurred in one of the commercial flocks. Forty-one of 50 isolates of MS-H obtained from vaccinated flocks maintained their temperature-sensitive phenotype, but nine isolates showed a nontemperature-sensitive phenotype.
authors.affiliation: School of Veterinary Science, University of Melbourne, Parkville, Victoria, Australia.
authors.forename: J F
authors.initials: JF
authors.lastname: Markham
authors.forename: P C
authors.initials: PC
authors.lastname: Scott
authors.forename: K G
authors.initials: KG
authors.lastname: Whithear
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D001428:Bacterial Vaccines / Q000009:adverse effects; D002645:Chickens; D004269:DNA, Bacterial / Q000235:genetics / Q000302:isolation & purification; D004531:Eggs / Q000382:microbiology; D005260:Female; D018445:Infectious Disease Transmission, Vertical / Q000517:prevention & control / Q000662:veterinary; D008460:Meat / Q000382:microbiology; D009174:Mycoplasma / Q000235:genetics / Q000276:immunology* / Q000302:isolation & purification; D009175:Mycoplasma Infections / Q000276:immunology / Q000517:prevention & control / Q000662:veterinary*; D010058:Oviposition; D012150:Polymorphism, Restriction Fragment Length; D011201:Poultry Diseases / Q000276:immunology* / Q000517:prevention & control
chemical_list: D000907:Antibodies, Bacterial; D001428:Bacterial Vaccines; D004269:DNA, Bacterial