DANGERS OF EATING RAW FRESH WATER FISH…may even cause LIVER CANCER
Dear all Raw Fish Lovers,
I hope of you will take great care when eating raw unfrozen fresh water fish as this can be very dangerous to your health. Fresh water fish from the tropics and for that matter, all raw meat, contain a lot of dangerous parasites.
It was recently reported in the journal "PLoS Pathogens" that a chronic infection with a type of flatworm called Opisthorchis viverrini or South East Asian Liver Fluke can cause liver cancer. In fact, the International Agency for Research on Cancer has classified Opisthorchis viverrini as a Class One carcinogen. If untreated, about 33% of the estimated nine million people infected by this worm from eating raw fresh water fish is expected to develop liver cancer!
Eating raw fresh water fish is extremely dangerous. Over the years I have seen a fair number of patients infected with another fresh water worm called Gnathostomiasis spinigerum especially after my patients eat raw fish during the Chinese New Year. Migration under the skin causes intermittent, migratory, painful itchy swellings (cutaneous larva migrans). Patches of swelling appear after the above symptoms clear. These lesions vary in size and can be accompanied by itching, rash, and stabbing pain. Swellings may last for 1 to 4 weeks in a given area and then reappear in a different location. Initially when the worms migrate to the gallbladder area it may cause so much pain and discomfort that it is mistaken for inflammation of the gallbladder (cholecystitis) and many of the patients have the gallbladder removed because of wrong diagnosis. Migration to other tissues (visceral larva migrans), can result in cough, bloody urine, eye involvement, meningitis, encephalitis and eosinophilia. Eosinophilic myeloencephalitis may also result from invasion of the central nervous system by the larvae.
It has been reported that the worm can live in the body for as long as 11 years, and during that time it will be crawling all over the body and if it gets into the brain or eye and die there, it may cause blindness and epilepsy years later.
The Japanese are much smarter as they eat only salt water fish. However, this is not very safe either because as high as 40% of sea fish like cod and salmon do carry other types of worms like Anisakis simplex and the 30 feet long fish tape worm called Diphyllobotrium latum and many other parasites. Moreover, the Japanese freeze the fish at below minus 20 degrees Centigrade for many days to kill some of these parasites before eating them. Home freezers are not cold enough to kill the parasites. In the USA it is mandatory for fish that is served raw to be frozen to below minus 20 degrees Centigrade for at least 7 days.
To be safe it is best not to eat any fish or other meat raw. Cooking will of course, kill all parasites and render all flesh and meat safe to eat. So when you are in any of the tropical countries and especially when in South East Asia. think twice before going to the Sushi bar.
Dr Looi