What disease causes swollen sheep joints

Caprine viral arthritis is not a literal problem with goats' joints, but a viral encephalitis that is common in sheep herds. It is contagious and is generally divided into three categories: encephalomyelitis type, arthritis type, and pneumonia type. Because the symptoms are different, the age of onset is also different. This article introduces the specific content of goat viral arthritis. If you don’t know about it, you can take a look and learn about it.

Caprine viral arthritis-encephalitis is a viral infectious disease.

Clinical characteristics

Adult sheep suffer from chronic polyarthritis, occasionally accompanied by interstitial pneumonia or interstitial mastitis; lambs often show symptoms of encephalomyelitis.

Clinical symptoms

It is divided into three types based on clinical manifestations. Encephalomyelitis type, arthritis type and interstitial pneumonia type. Most of them occur independently, but a few overlap. However, during autopsy, most cases had two or three of these pathological changes.

1. Encephalomyelitis type: incubation period 53-131 days. It mainly occurs in lambs aged 2-4 months and has obvious seasonality. More than 80% of cases occur between March and August, and are obviously related to late winter and spring lambs. At the beginning of the disease, the sheep are depressed and lame, and then their limbs become stiff or ataxia. Paralysis of one or more limbs, inability to lie down, limb tremors, some cases of nystagmus, panic, opisthotonos, tilted head and neck or circular motions. Sometimes facial nerve paralysis, difficulty swallowing, or blindness occurs. The course of the disease is half a month to 1 year. Some surviving cases still have sequelae. A few cases also have symptoms of pneumonia or arthritis.

2. Arthritis type: occurs in adult goats over 1 year old, with a course of 1-3 years. Typical symptoms are wrist swelling or lameness. The knee and hock joints may also be affected. The condition may worsen gradually or occur suddenly. Initially, the soft tissues around the joints become edematous, damp, hot, fluctuating, and painful, with varying degrees of lameness. Then the joints swell into fists, making movement difficult, and it is common for the patient to kneel on the front knee and crawl. Sometimes the sick sheep have swollen lymph nodes in front of the shoulder. Fluoroscopic examination showed edema of soft tissue around joints in mild cases; tissue necrosis, fibrosis or calcification in severe cases, and yellow or pink joint fluid.

3. Pneumonia type: less common. There is no age limit, the course of the disease is 3-6 months, the affected sheep progressively lose weight, cough, have difficulty breathing, have dullness on chest percussion, and dull rales on auscultation. In addition to the above three types of disease, interstitial mastitis sometimes occurs in lactating ewes.