Mycoplasma hyorhinis swine arthritis.

The belief that rheumatoid arthritis may be of infectious origin has led us to studies of mycoplasmal arthritidies of swine as a potential animal model (1). In parallel with the previously reported study of Mycoplasma hyorhinis arthritis in conventional Yorkshire swine, a pilot study of the disease in a miniature strain of swine was undertaken on the grounds that a susceptible miniature breed would facilitate subsequent expanded investigations of the process. This report details our observations on experimentally infected and control miniature swine of the Piney Woods strain. In striking contrast to Yorkshire swine, a chronic arthritis was not induced in the miniatures, thus emphasizing previously recognized breed differences in the biological response to M. hyorhinis infection (W. P. Switzer, personal communication) and calling to mind the vague concepts of "genetic susceptibility" that have been discussed in reference to rheumatoid arthritis (3).