title: Determination of the effective dose of the live Mycoplasma synoviae vaccine, Vaxsafe MS (strain MS-H) by protection against experimental challenge.
abstract: The minimum effective dose of the Mycoplasma synoviae-H (MS-H) vaccine was determined through protection against experimental challenge. Chickens were vaccinated by eyedrop with the following doses of a vaccine: 1.2 x 10(5), 2.4 x 10(5) 4.8 x 10(5), 9.6 x 10(5), 1.92 X 10(6), and 3.84 X 10(6) color change units (CCU), then challenged 6 wk after vaccination. Rapid serum agglutination results indicated that 100% of birds receiving an MS-H dose of > or = 4.8 x 10(5) CCU had antibodies to MS and enzyme-linked immunosorbent assay results showed that 60% of birds receiving a dose of 4.8 x 10(5) or 9.6 x 10(5) CCU and 100% of birds receiving a dose of 1.92 x 10(6) or 3.84 x 10(6) had antibodies to MS. At postmortem after challenge, the following parameters were significantly lower in birds vaccinated with an MS-H dose of > or = 4.8 x 10(5) CCU: air sac (AS) lesion severity; incidence of AS lesions; mucosal thicknesses in the upper trachea, middle trachea, and lower trachea (LT); and MS colonization of the LT and AS. It was concluded that an MS-H dose of 4.8 x 10(5) CCU was sufficient to elicit an antibody response in birds, prevent MS colonization in the LT and AS, and protect against AS lesions caused by an experimental MS and infectious bronchitis virus challenge.
authors.affiliation: School of Veterinary Science, The University of Melbourne, Werribee, Victoria, 3052, Australia.
authors.forename: Jillian F
authors.initials: JF
authors.lastname: Jones
authors.forename: Kevin G
authors.initials: KG
authors.lastname: Whithear
authors.forename: Peter C
authors.initials: PC
authors.lastname: Scott
authors.forename: Amir H
authors.initials: AH
authors.lastname: Noormohammadi
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D001428:Bacterial Vaccines / Q000008:administration & dosage* / Q000276:immunology*; D002645:Chickens / Q000276:immunology* / Q000382:microbiology; D009175:Mycoplasma Infections / Q000276:immunology / Q000517:prevention & control / Q000662:veterinary*; D045805:Mycoplasma synoviae / Q000276:immunology*; D011201:Poultry Diseases / Q000276:immunology* / Q000517:prevention & control*; D020545:Respiratory Mucosa / Q000473:pathology; D013047:Specific Pathogen-Free Organisms; D014132:Trachea / Q000473:pathology
chemical_list: D000907:Antibodies, Bacterial; D001428:Bacterial Vaccines