Consumption of soft-shelled turtles found to spread cholera

Consuming soft-shelled turtles might spread cholera - a life- threatening diarrhoeal disease, according to a new Chinese study.

A pathogen called Vibrio cholerae could colonise  the surfaces, as also the intestines of soft shelled-turtles, according to researchers.

Researchers from Chinese Centre for Disease Control and Prevention inserted the genes producing bio-luminescent proteins into V cholerae that allowed the researchers to directly observe the pathogens colonising the turtles.

The team infected turtles, by dipping them in a phosphate buffered saline solution containing the now bio-luminescent bacteria, serogroup 0139.

The turtles were checked for the next four days at 24 hour intervals. The first light signals were detected at 24 hours and at 96 hours, the entire dorsal side of the turtles' shells was emitting bio-luminescence. 

The bio-luminescence was also detected on the dorsal side of the turtles' limbs and necks, and in the calipash, the gelatinous protoplasm, regarded as a delicacy, that lay directly beneath the shells' surface.

It was more difficult to determine intestinal colonisation. The turtles were inoculated intragastrically with the bio luminescent V cholerae.

As digestion took roughly 34 to 56 hours in 150 gramme turtles, the investigators euthanised and dissected the turtles at 72 hours, and checked all their internal organs. The researchers were able to find bioluminescence only in the intestines.  

The research was conducted after it was observed, through surveillance of the disease in China, that consumption of cholera-carrying soft shelled turtles had caused outbreaks of the disease, said corresponding author Biao Kan, PhD.

"Cholera is a life-threatening diarrhoeal disease," said Kan, who is professor of pathogenic biology and infectious disease control, at the Chinese Center for Disease , PTI reported.