Arthritis and Associated Etiologic Agents

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Diseases and agent Age group affected Nature of lesions Signs, other lesions, comments

Mycoplasmal polyserositis/arthritis

Mycoplasma hyorhinis

3-10 weeks. Occasionally in young adults.

Swollen joints, serosanguinous or serofibrinous synovial fluid. Later, perhaps pannus and joint erosion. Acute onset and lameness, fibrinous pericarditis, pleuritis, peritonitis singly or in combinations. Abdominal tenderness with sternal recumbency. Morbidity <25%, mortality usually low.

Mycoplasmal arthritis

Mycoplasma hyosynoviae

8-24 weeks Excessive serosanguinous joint fluid. Later, yellow membranes, perhaps pannus. Stiffness, shifting lameness. Hind leg lameness common. Many slowly recover. Morbidity 1-50%, mortality low.

Glasser’s disease

Haemophilus parasuis

Pigs from 2 weeks to 4 months old. Occasionally in young adults. Swollen, painful, fluctuating joints with turbid fluid or green fibrin. Periarticular inflammation. Classic lesions: serofibrinous or fibrinopurulent pleuritis, pericarditis and peritonitis or combination. Frequently meningitis and convulsions. Often affects best pigs.

Streptococcal arthritis

Streptococcus suisType 2

In weaners and growers up to market weight. Acute suppurative polyarthritis. Meningitis common. If meningitis, then CNS signs. Often fatal in weaners and growers. Can be epidemic with incidence up to 15%. Occasionally, valvular endocarditis.

Streptococcal arthritis

Streptococcus equisimilis

Suckling and postweaning pigs. Hot swollen joints. Increased turbid synovia. Perhaps periarticular fibrosis, abscesses. Accompanied by fever, depression and other evidence of septicemia. Endocarditis occasionally in older pigs.


Erysipelothrix rhusiopathiae

Young growing, weaned pigs. Also in finishers with acute erysipelas. Growers: joint(s), especially hocks, knees, toes are swollen, painful; joint(s) decrease in size but remain enlarged. 
Finishers: limited swelling, severe pain.
Growers: Number of swollen points in herd increases, often without an acute outbreak or much mortality.
Finishers: Acute arthritis often a part of acute erysipelas. Identify erysipelas by culture of parenchymatous organs and acutely inflamed joints.
Septic arthritis
Other bacteria
Neonates to piglets a few weeks old. One or several painful, swollen joints. Commonly caused by metastatic bacteria from infected navel, skin erosions/ulcerations at other sites.


*  Joints of knees, hocks, toes more visibly affected. Also examine shoulder, stifle, atlanto-occipital joints.  Culture joints, parenchymatous organs.

CNS- central nervous system