Common Symptoms of Sheep Bluetongue Disease and Prevention and Treatment Methods

Symptoms: The incubation period is 3 to 8 days. At the onset of the disease, body temperature rises to 40.5°C to 41.5°C and remains elevated for 2 to 3 days. Shortly after the temperature rises, affected sheep show anorexia, depression, and lag behind the flock. The upper lip swells, and the edema may extend to the face and ears; there is drooling, and the oral mucosa becomes congested and purplish-blue. Soon afterward, erosions appear on the lips, gums, cheeks, and tongue mucosa, making swallowing difficult. The oral mucosa is damaged by ulcers, with local blood oozing, and the saliva turns red. Secondary infection can cause local tissue necrosis and bad breath. The nose discharges purulent secretions, which form scabs and block airflow, causing difficulty breathing and snoring sounds. Inflammation of the coronary band and laminae leads to lameness, kneeling, and lying motionless. Sick sheep become emaciated and weak, with constipation or diarrhea, sometimes bloody diarrhea. Leukopenia appears early. The course of the disease is generally 6 to 14 days, and hoof lesions may recover after 6 to 8 weeks. The incidence rate is 30% to 40%, and the mortality rate is 2% to 30%, reaching as high as 90%, with most deaths due to concurrent pneumonia and gastroenteritis. In ewes at 4 to 8 weeks of pregnancy, if live vaccine or immunizing infection is used, about 20% of the lambs they deliver develop malformations, such as hydrocephalus, cerebellar hypoplasia, and excessive gyri.

Prevention and Treatment: (1) Do a good job of draining pastures and eliminating midges, and persist with sheep medicated baths and deworming. Strengthen feeding management and maintain good sanitation. (2) In areas where the disease is epidemic, vaccinate every year. (3) Sick sheep can be treated with sulfonamides or antitoxin.