HERD HEALTH
PIH-36
pork industry handbook
PURDUE UNIVERSITY • COOPERATIVE EXTENSION SERVICE • WEST LAFAYETTE, INDIANA
Swine Arthritis
Authors:
Richard Ross, Iowa State University
Michael Hill, Purdue University
Richard L. Wood, Ames, Iowa
Reviewers:
LeRoy Biehl, University of Illinois
Julie Ann Feeser, Taneytown, Maryland
Dave and Marty Huinker, Decorah, Iowa
Duane Miksch, University of Kentucky
Arthritis is commonly recognized as a major factor in swine lameness. The disease is caused by infection of the joint and the surrounding tissues by bacteria or mycoplasmas. United States Department of Agriculture (USDA) meat inspection records indicate that trimming the swine carcasses and discarding whole carcasses due to arthritis are leading causes of loss at slaughter. Of greater concern is the economic loss that occurs on the farm because of slower and less efficient gains and reduced performance by adult breeding stock and lactating sows. Death loss occurs in some instances but is not a major factor.

Other factors in lameness in swine include those related to nutritional imbalances or deficiencies, foot and leg lesions resulting from trauma and improper conformation and degenerative bone and joint changes.

Streptococcal Arthritis
Streptococci cause acute and chronic arthritis in swine of all ages. Most commonly this infection occurs in baby pigs where the disease may be identified as part of the “joint-ill” syndrome associated with navel infection.

The streptococci are classified serologically according to the Lancefield system. Representatives from virtually every one of the Lancefield groups have been isolated from swine; however, most isolates from naturally occurring arthritis belong to Group C (Streptococcus equisimilis), Group L, or Group D (Streptococcus suis).

Besides neonatal diarrhea and pneumonia, streptococcal infection is probably one of the most common diseases affecting young pigs. Streptococcal infection occurs under many types of management and environmental conditions. The organisms are common in vaginal secretions, respiratory tract secretions and sow milk. Streptococcus suis may be carried in the tonsils of clinically healthy animals. These organisms invade the pig’s body by way of the navel, foot or skin wounds or the tonsils. Rough flooring or bedding material causes abrasions of the legs of nursing pigs that undoubtedly facilitate invasion by these organisms.
Streptococcal arthritis never affects a large percentage of pigs; the disease condition (morbidity rate) is usually less than 5%. Ten to 20% of affected pigs may die, either as a result of systemic lesions produced during the septicemic (pathogenic bacteria in the blood) stage of the disease or by causes related to impaired mobility (starvation, overlaying, etc.).

Clinical Signs. Acute streptococcal infection is characterized by a fever, roughened hair coat, depression and lameness. As the disease progresses, the affected pig may lose weight and have marked enlargement of the affected joints. One or several joints may be involved; swelling is most often observed in the knee, elbow and hock joints. The pain associated with the condition and the resulting impairment of movement restrict the ability of affected pigs to nurse.

Affected pigs are often stunted and have chronic arthritis for life. Affected joints contain increased amounts of cloudy joint fluid with clots of fibrin. There is swelling, discoloration and redness of the membranes. The connective tissue capsule around the joint is thickened and may contain small abscesses. As the disease becomes chronic there may be damage to the articular cartilage. Lesions also are observed in the growth plates of the bones. Other signs indicative of systemic infection also may be seen, particularly in S. suis infections.

Diagnosis. A sudden lameness with joint enlargement and a fever in pigs 1 to 3 weeks of age is highly suggestive of streptococcal arthritis. Joint and bone lesions also are very suggestive. Systemic lesions, such as enlargement and congestion of the lymph nodes, polyserositis (inflammation of the serous membrane), pneumonia, or meningitis are seen along with the arthritis in S. suis infections. The organisms can be isolated from the acutely arthritic joints by bacteriologic culture technics.

Prevention and Treatment. The recommended treatment in cases of baby pig arthritis is generally penicillin. Treatment is most effective if initiated before the disease is advanced. If inflammation has become chronic, the response to treatment
Cooperative Extension work in Agriculture and Home Economics, state of Indiana, Purdue University, and U.S. Department of Agriculture cooperating; H. A. Wadsworth, Director, West Lafayette, IN. Issued in furtherance of the acts of May 8 and June 30, 1914. The Cooperative Extension Service of Purdue University is an affirmative action/equal opportunity institution.