PCR Detection and Pathohistological Analysis of Ranavirus Infection in Alligator Snapping Turtle

In March 2013, two diseased alligator snapping turtles(Macrochelys temminckii) were collected from an aquarium in Chengdu(Sichuan Province, China) and they were transferred to the Key Laboratory of Animal Disease and Human Health of Sichuan Province. Symptoms included energetic dispirited, crawled in weakness,slowed response to external stimulation; local redness and swelling in the neck and limbs, as well as plastron ulcerated and perforated(Fig. 1). Bacteriologic test, pathological observation and PCR detection were performed to identify the etiological factors of these two alligator snapping turtles. Bacteriologic test was negative; histopathologically, the lesions appeared in multi-organs and tissues, especially in the kidney, liver, lung and heart. The main pathologic lesions were degeneration, necrosis and infiltration of the inflammation cells, with acidophilic or basophilic cytoplasm of inclusions. Intracytoplasmic inclusions were found in various cell types(Fig. 2). In addition, The PCR results of two samples were positive for Ranavirus. A 500 bp fragment(Fig. 3) of the major capsid protein gene was amplified and sequenced. Gen Bank BLAST searches on the sequences revealed an identitiy of 95% to 99% with that of Ranavirus. From the PCR results and pathological observation, we speculated that Ranavirus infection had caused the death of the alligator snapping turtles.