Results
The morbidity sketch, clinic symptom and pathological lesions
According to the statement of the raccoon dogs’ owners and the scene investigation, the clinic features of the diseased raccoon dogs are described as following: the first case occurred 4 weeks before; in a recent month, 47% (425/896) of raccoon dogs showed some abnormal symptoms, and 17.6% (75/425) among the abnormal ones were too severe to stand or walk, and 4.2% (18/425) were dead. The disease in young raccoon dogs was earlier that that in adult ones, there were no difference between the male and the female.
The symptoms in the early stage: depression, slow responses, loss of appetite, significant reduction of food intake, increase of body temperature by 0.5 ~ 1.0℃, disordered coat, curling, and mucus secretion in the nasal cavity.
The symptoms in the typical clinic stage: the disease in most raccoon dogs was characterized by the symptoms such as suppuration of skin or/and joints and severe respiratory dysfunction. The suppurative focus mainly occurred in the limb joints, skins, neck, shoulder, groin, etc; sometimes pustule burst with yellow-white pus, blood and tissue fluid. The respiratory dysfunction showed cough, sneezing, asthma, shortness of breath, cyanosis of visible mucosa, sticky secretion in the nasal cavity, severe purulent nasal juice, dyspnea and abdominal breathing in most sick raccoon dogs.
The symptoms in the later stage: weak physique, emaciation, unstable standing, multiple organs failure, death.
Pathological autopsy: The diseased raccoon dogs in the typical clinic stage were dissected and the lesions were as following: swollen with ulceration (Fig.1A) and yellow-white pus (Fig.1B) in the tarsal joint of the hind limb; some or diffuse hemorrhagic spots or plaques on the surface of the bladder (Fig.1C); lots of effusion fluid in pleural, many hemorrhagic spots in diaphragm (Fig.1D); lots of mucous secretions in the larynx and trachea, and many hemorrhagic spots, hyperemia, white inflammatory exudation in the lungs (Fig.1E); needle-like hemorrhagic spots in the epicardium and no pericardial effusion in the pericardium (Fig.1F); hepatomegaly, lobulation, partial yellowing, gallbladder filling (Fig.1G); clear hemorrhagic spots in the kidney, whitening of renal capsule (Fig.1H); splenomegaly, catarrhal inflammation in intestinal mucosa; congestion and hemorrhagic spots in jejunal mucosa; many bleeding spots in the initial segment of ileum; many bleeding spots in some intestinal lymph nodes.
Based on the above clinic symptoms, the disease in raccoon dogs was suspected to be Staphylococcus infection.