Pathology of Coinfection of Mycoplasma hyorhinis and Aerococcus urinae Causing FiBrinous Pericarditis in a Piglet - A Case Report

Fibrinous pericarditis due to co infection with Mycoplasma hyorhinis and Aerococcus urinae is rarely reported in pigs. In this case report, a one-month crossbreed male piglet with sudden death was diagnosed with fibrinous pericarditis based on necropsy, microbiological and PCR assay. The thoracic cavity was filled with large amounts of serosanguineous fluids mixed with fibrins and thickened pericardial sac adhered to the epicardium looked like bread-and-butter appearance. The cranioventral lobes of lungs showed consolidation with fibrinous exudate. Histopathology of epicardium showed fibrocellular exudates and lungs showed hyperplastic changes with congestion. The antigen of Mycoplasma hyorhinis was demonstrated in heart and lungs. Bacteriological analysis of the heart blood and spleen showed the pure growth of Aerococcus urinae. The genomic DNA of heart, lungs and spleen showed positive amplification of Mycoplasma hyorhinis targeting 16srRNA gene. The present case was diagnosed as fibrinous pericarditis in piglet due to M. hyorhinis with coinfection of Aerococcus urinae, which is often overlooked as a risk factor.