title: Quantification of the horizontal transmission of Mycoplasma synoviae in non-vaccinated and MS-H-vaccinated layers.
abstract: The number of newly infected birds attributable to one infectious bird per day (= transmission rate β) was assessed in non-vaccinated and MS-H-vaccinated experimental specified pathogen-free White Leghorns after Mycoplasma synoviae challenge. Furthermore, the effect of vaccination on the shedding of the challenge strain was determined. The following groups were made: a negative control group (n = 5), a vaccinated (MS-H vaccine by eye drop (>105.7colour changing units/bird)) non-challenged group (n = 5), two non-vaccinated challenged groups (n = 18 each) and two vaccinated challenged groups (n = 18 each). In the challenged groups, six seeder birds were intratracheally inoculated with 105.4colony forming units (CFUs)/bird. Trachea swabs were taken at day (D)2, D3, D4, D5, D7, D9, D11, D14, D17, D21, D25, D28, D32, D35, D42 and D46 after contact with seeders and analyzed with a quantitative PCR able to detect the vaccine and field strain separately. The transmission rate and shedding were estimated using the susceptible exposed infectious transmission model and a linear mixed model, respectively. The mean shedding of the challenge strain was 106.4CFU equivalents M. synoviae/g trachea mucus in vaccinates shedding MS-H, while in the birds not shedding the vaccine (non-vaccinates and vaccinates not shedding MS-H) it was 106.9CFU equivalents M. synoviae/g trachea mucus. In vaccinates shedding MS-H, β was 0.0012 (95% C.I.: 0.00048 - 0.0024), while in birds not shedding vaccine (non-vaccinates and vaccinates not shedding MS-H) a significantly higher β of 0.022 (95% C.I.: 0.015 - 0.031) was found.
authors.affiliation: a GD - Animal Health , Deventer , The Netherlands.
authors.forename: A
authors.initials: A
authors.lastname: Feberwee
authors.affiliation: a GD - Animal Health , Deventer , The Netherlands.
authors.forename: R
authors.initials: R
authors.lastname: Dijkman
authors.affiliation: b National Institute for Public Health and the Environment, Ministry of Health, Welfare and Sports , Bilthoven , The Netherlands.
authors.forename: D
authors.initials: D
authors.lastname: Klinkenberg
authors.affiliation: a GD - Animal Health , Deventer , The Netherlands.
authors.forename: W J M
authors.initials: WJM
authors.lastname: Landman
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D001428:Bacterial Vaccines / Q000276:immunology*; D002645:Chickens; D005260:Female; D009175:Mycoplasma Infections / Q000382:microbiology / Q000517:prevention & control / Q000635:transmission / Q000662:veterinary*; D045805:Mycoplasma synoviae / Q000276:immunology / Q000502:physiology*; D011201:Poultry Diseases / Q000382:microbiology / Q000517:prevention & control* / Q000635:transmission; D012698:Serologic Tests; D013047:Specific Pathogen-Free Organisms; D014132:Trachea / Q000276:immunology / Q000382:microbiology
chemical_list: D000907:Antibodies, Bacterial; D001428:Bacterial Vaccines
keywords: M. synoviae; Quantification; layers; transmission; vaccination