Absence of strictly age-related resistance to Mycoplasma hyosynoviae infection in 6-week-old pigs.

Mycoplasma hyosynoviae has never been reported to cause arthritis in pigs younger than 10 weeks of age. In order to investigate whether a strict age-related resistance exists, four 6-week-old pigs and four 13-week-old pigs, all immunologically naïve with respect to M. hyosynoviae, were inoculated intranasally with the agent and autopsied at day 11 or 13 after infection.

Use of a novel serum ELISA method and the tonsil-carrier state for evaluation of Mycoplasma hyosynoviae distributions in pig herds with or without clinical arthritis.

A novel indirect ELISA test using deoxycholate extracted antigens coated onto a hydrophobic polystyrene surface for measurement of serum antibodies specific for Mycoplasma hyosynoviae was developed. Sensitivity and specificity of the test were found to be superior to previous ELISAs as tested on porcine serum following experimental Mycoplasma infections as well as by analysis of samples from one Danish herd known to be free of M. hyosynoviae and samples from two Norwegian herds without clinical suspicion of M.