SYMPTOMS OF ARTICULAR RHEUMATISM IN SWINE.
Climatic influences. Rheumatoid. Joints attacked. Muscles. Decubitus. Stiff, rigid, steps on toes, grunts, swelling, heat, tenderness, chaps, cracks, suppurations, inappetence, emaciation, metastasis, cardiac disorder. Duration; course. Chronic form. Muscular form. Diagnosis from trichinosis. Connection with arthritis. Metastasis. Remissions.
The pig which shows an extreme sensitiveness to climatic vicissitudes and cold winds, fleeing instantly to his lair on their advent, is yet protected by his subcutaneous fat, so that he is not a frequent victim of simple rheumatism. Leblanc attributes it to unwholesome pens. Chaussade to too rapid fattening (overfeeding). Rheumatoid attacks are very common at the onset of hog cholera, swine plague and other infectious diseases, when they are probably but local manifestations of the general infection.
The lesions are mainly concentrated in the stifle, hock, knee and fetlock. In some cases the dorsal and lumbar muscles suffer and there is arching of the back with great tenderness on manipulation. In other cases the muscles of the quarter or shoulder are involved as shown by their stiffness and extreme sensibility to touch.
The pig is found down, indisposed to rise, and when up, stands drawn together with limbs rigid and feet resting on the toes. He will often point one toe to the ground repeatedly, before resting on the foot, or shift the weight uneasily from foot to foot. If moved he grunts plaintively and if handled squeals.
The affected joints may be surrounded by hot tender swellings or they may be nearly normal in outline, but they are always very sensitive to pressure and above all to flexion and extension, and the skin is usually hyperæmic and red. There may be engorgements of the lymphatics on the inner side of the limbs, and chaps and cracks in the flexures of the joints. Suppurations may follow (Graignard) suggesting a complex infection.
There is little appetite and though the disease becomes subacute or chronic there is a steady loss of condition or at least a failure to thrive.
Benion’s reference to a coincident or sequent inflammation of the respiratory or digestive organs and Spinola’s similar reference to pleurisy are strongly suggestive of swine plague and hog cholera. Any manifest disposition to shift from one part to another and any concurrent disorder of the heart, other than simple palpitation is strongly confirmatory of rheumatism.
The disease tends to recovery in from four to twenty days, or to pass into the chronic form. In this state the symptoms are materially mitigated. Fever is absent, but the appetite, digestion and assimilation are poor, the animal remains stunted, emaciated or unthrifty, there is a disposition to lie most of the time under the litter, and when up it moves stiffly with short steps, semi-flexed joints and upright digits. Sometimes the joints are permanently swollen and rigid by reason of thickening and shortening of the binding ligaments, by the organization of false membranes or by anchylosis.
Muscular Rheumatism in Swine. This appears to be rarely seen as an independent disease, but appears at times to coincide with the arthritic form. In such cases the back is arched and very sore to the touch or to pressure. It must be distinguished from the muscular soreness of trichinosis which occurs in infested localities, after trichinous food or water, is preceded by digestive disorder and diarrhœa, and by the passage of the nearly microscopic worms in the stools, and is independent of arthritis.
Muscular rheumatism leads to atrophy of the muscles, especially those of the quarters, and this may resemble, somewhat, partial paraplegia from disease of the spinal cord. Its connection with arthritis, its tendency to shift from place to place, to undergo ameliorations and relapses, and its exquisite tenderness, serve to distinguish it from paralysis.