Actinobacillus suis-associated iliac thromboembolism caused acute posterior paralysis in a young boar

A 5-month-old imported boar showed posterior paralysis upon arrival in Japan. Both limbs had coldness, algesia, and thigmesthesia. A thrombus was detected from the abdominal aorta to the left external iliac artery. Irregular vegetation was observed on the left atrioventricular valve. The skeletal muscles in the hind limb appeared like boiled meat. The histological diagnoses were endocarditis, glomerulonephritis, and meningoencephalitis with Gram-negative bacilli as well as diffuse intravascular coagulation and diffuse alveolar damage. The bacilli were identified as Actinobacillus suis via immunohistochemistry and 16S rRNA gene sequencing. This is the first case report of acute posterior paralysis due to iliac thromboembolism in swine with A. suis infection. Iliac thromboembolism should be considered if posterior paralysis is observed in swine.