Pathogenesis of bovine mycoplasma mastitis
Jasper, D.E.; Boothby, J.T.; Thomas, C.B.
Israel Journal of Medical Sciences 23(6): 625-627
1987
ISSN/ISBN: 0021-2180 PMID: 3312100 Document Number: 296723
Most bovine mastitis due to mycoplasmas is initiated by passage of mycoplasmas through the teat canal into teat and gland cisterns. Within a few days, mycoplasma numbers increase to 106-108, and cows react with a strong inflammatory response. Alveolar epithelium undergoes degenerative changes and exudate replaces milk secretion. The interstitium between alveoli is invaded with lymphocytes, macrophages, plasma cells and fibroblasts. Extent and duration of these changes vary greatly. In milder cases, they may be reversed within days or weeks with a return to normal or reduced milk production. Often, destruction and atrophy of alveoli are complete with extensive fibrosis throughout the udder. Milk ducts may undergo invasive and obliterative fibrosis. Cell-mediated responses are suppressed, while hypersensitivity is suspected of enhancing the adverse responses. Immunity in cows that recover is variable and of limited duration.