The Palaemonetes sinensis aquaculture industry in Panjin City, Liaoning Province, China, experienced heavy losses in October 2018. Morbidity of cultured shrimp reached 50% and was characterized by cloudiness of muscle and the gradual spread of disease within the population. When the infection was mild, histopathological examinations revealed that the muscle cells contained a considerable number of microorganisms. In extreme cases, the structure of the hepatopancreatic glandular and muscle fiber was obscured or even vanished. Electron microscope observations revealed the presence of granular cytoplasmic inclusions in cells from hepatopancreas and muscle tissues. The 16S rDNA sequence of the intracytoplasmic organism was 94.7% identity to that of Coxiella burnetii. This is the first report of infection by C. burnetii in P. sinensis.
Keywords: Histopathology; Palaemonetes sinensis · Coxiella burnetii.