Histopathology of enzootic chronic polyarthritis of goats in Japan
Nakagawa, M.; Motoi, Y.; Iizuka, M.; Azuma, R.
National Institute of Animal Health Quarterly 11(4): 191-200
1971
ISSN/ISBN: 0027-951X PMID: 5142165 Document Number: 39618
Over eight years, 226 out of 506 Saanen kids born on one farm, as well as many adults, were affected. Incidence was higher in summer, and in pregnancy or lactation. Disease often persisted for several years, and recovery was rare. Leg joints, often both sets of carpals, showed hot or cold swelling, causing varying degrees of lameness. P.M. specimens from eight goats showed increased synovial fluid, thickening of capsules and chalky deposits in joint cavities and capsules. Exudative and proliferative inflamation occurred, particularly in the synovial membrane. Affected goats had hyperaemia, oedema and infiltration of lymphocytes, plasma cells and histiocytes, fibrous thickening of the connective tissue, and diffuse necrosis of the synovial membrane. In late stages, hyperplasia of villi occurred. Twelve 2-month-old kids nursed by affected females were given s/c injections of adrenaline or deoxycorticosterone acetate, and i/v in ocula of corynebacteria or streptococci. Eight developed symtpoms within a week; two were killed immediately, two continued to show symptoms for four months, and four recovered. A similar flora (including corynebacteria, streptococci and staphylococci, but no mycoplasma) was obtained from naturally and artificially infected joints, lymph nodes and viscera. There was no relation of flora to occurrence of disease, type of lesion or even strain used to promote artificial infection. Injection of bacteria alone did not promote infection, indicating that stress (e.g. pregnancy, summer heat or hormone injection) is a requisite for pathogenicity.