Beware! Consuming those soft shelled turtles may prove deadly

Beware the dangers of eating seafood! A study has recently found that soft shelled turtles, zooplankton, fish, waterfowl, crab, lobster, shrimp are likely to spread the cholera in humans.

Cholera is a bacterial disease causing severe diarrhoea and dehydration, usually spread in water.

Besides soft shelled turtles, aquatic hosts of V. cholerae include zooplankton, fish, shellfish, egg masses of midges, waterfowl, and crustaceans. Fish and shellfish are proven to spread this disease.

According to researchers, the pathogen, Vibrio cholerae can colonise the surfaces, as well as the intestines of soft shelled turtles.

To infect the turtles, the investigators dipped them in a phosphate buffered saline solution containing the now bioluminescent bacteria, serogroup 0139.

Over the next four days, they checked the turtles at 24 hour intervals.

The findings indicated that initially light signals were detected at 24 hours and then after 96 hours, the entire dorsal side of the turtles' shells was emitting bioluminescence.

The latter was also easily detected on the dorsal side of the turtles' limbs and necks and in the calipash, the gelatinous protoplasm, locally regarded as a delicacy that lies directly beneath the shells' surface.

The turtles were inoculated intragastrically with the bioluminescent V. cholerae.

Knowing that the digestion takes roughly 34 to 56 hours in 150 gram turtles, the team euthanised and dissected the turtles at 72 hours and checked all their internal organs.

Bioluminscence could be detected only in the intestines.

They also identified the different colonisation factors--molecular machinery on the surface of V. cholerae--that enabled the bacteria to stick to the turtles' dorsal surfaces and intestines.

Through surveillance of the disease in China, corresponding author Biao Kan said that cholera is a life-threatening diarrheal disease and consumption of cholera-carrying soft shelled turtles had caused outbreaks of the disease,

He also noted that the O139 serogroup, the major strain spread by the turtles, is an emerging disease in China.

A side benefit of the study is that the soft shelled turtle could serve as a new animal model for studying how V. cholerae interacts with aquatic hosts.

The research is published in journal of Applied and Environmental Microbiology.