Seafood Lovers, Pay Attention: Eating Soft Shell Turtles May Spread Cholera

A new Chinese study warns that consuming soft shell turtles may put you at the risk of contracting cholera. According to researchers from Chinese Centre for Disease Control and Prevention, a pathogen called Vibrio cholerae can settle on the surface as well as the intestines of soft shelled turtles which, when consumed, can be harmful for human health increasing the risk of cholera. Soft shells turtles are considered to be a delicacy in China and are now being blamed for spreading this highly infectious disease. This new study, published in the journal Applied and Environmental Microbiology, shows how the consumption of soft shell turtles may be linked to the deadly cholera outbreaks in China.

Cholera is a bacterial infection that causes severe diarrhoea and dehydration. It spreads to contaminated food and water. The symptoms may start appearing as soon a few hours or within five days of being infected. The first few signs of cholera are mild such as watery diarrhoea, excessive thirst, vomiting and muscle cramps. Cholera is treatable with the help of antibiotics and oral or intravenous solutions. However, it can be fatal and may even lead to seizures if not treated right away. Traditionally, water was recognised as the primary vehicle for the spread of cholera but new studies are hinting at the fact that contaminated food may also play an important role in the transmission of the disease.

For the study, the team infected the turtles by dipping them in a phosphate buffered saline solution containing the bio luminescent bacteria, serogroup 0139. Over the next four days, the researchers examined the turtles at 24 hour intervals. They first detected light signals were observed after 24 hours. After 96 hours, the entire dorsal side of the turtles' shells was emitting bio luminescence. The latter was also easily detected on the dorsal side of the turtles' limbs and necks, and in the calipash, the gelatinous protoplasm, served as a delicacy, that lies directly beneath the shells' surface.

To determine intestinal colonisation, the turtles were inoculated intra-gastrically with the bio luminescent V cholerae. Since digestion takes about 34 to 56 hours in turtles, the investigators euthanized and dissected them after 72 hours, and examined all their internal organs. Bio-luminscence was only detected in the intestines of the turtles. The team also identified different colonisation factors such as the molecular machinery on the surface of V cholerae that enabled the bacteria to stick to the turtles' dorsal surfaces and intestines.

Although the study only pertains to soft shell turtles, it has been seen that other seafood delicacies such as zooplankton, shellfish egg masses of midges, waterfowl and crustaceans may be equally risky and contribute to the spread of cholera.
 
With inputs from Press Trust of India