Salmon infestation with tapeworm is on the rise. It has tripled from an average of .32 per 100,000 people to at least 1 case per 100,000 per year in kyoto ,Japan. As the craze for sushi and sashimi increased, so too has the worm spreads. Tapeworm can grow up to 25 feet inside your intestinal tract and will feast on your body’s nutrition, exhaust your body’s vitamin B12 causing severe anemia and weakening your body’s defenses by suppressing your immune system. In 2006, a Chicago man sued a restaurant claiming he had acquired a 15 foot tapeworm from eating an undercooked salmon salad.
Incidence of tapeworm and anisakis infection use to be restricted only to people of Scandinavian decent, as they are high consumers of gravlax, a lightly marinated salmon ( marinating salmon does not kill the tapeworm or anisakis larvae) and to Jewish woman who use fresh water fishes like pike,carp and white fish in preparing a traditional dish called gefilte fish. During the preparation, the woman taste the raw fish mixture to determine if the seasoning is adequate before cooking the dish. Lox is solely made from salmon,and is cured with salt and should be safe to eat, but is now another subject of study . Incidence of tapeworm and anisakis infestation has been found in South American ceviche and raw or green herring, a dish popular in the Netherland. Last Fall, CDC (Center for Disease Control) was prompted by an outbreak of fish tapeworm in California. Four individuals were affected. This individuals ate sushi which included salmon.
In the US, the salmon used in sushi bars are frozen and from salt water. The health department mandates that all seafood and fish used for preparing sushi and sashimi must be frozen before use to -10 deg F for 24 -48 hours before it is sold in the fish market. Avoid fresh water fish including wild salmon and striped bass, because they spend part of there life in fresh water. Also avoid pacific rock cod,also known as pacific red snapper ,as this fish eats the feces of sea lions and other marine mammals., so it can pick up parasites adopted to mammalian bodies. Halibut from the West has been found to have parasites. Fresh atlantic salmon is safe because all of these salmon are raised in salt water. The mackerels used in salad bars are marinated in vinegar , squid is purchased frozen, which kills the parasite . All Bonito fish is infested and is rarely served in US sushi bar except when serving Japanese clientile. In my research of articles regarding eating raw fishes, I have not encountered any mentioning tuna as a worm carrier.
Food and Drug Administration, sampled fish sold in Seattle, and found them to have no tapeworm but contain anisakis simplex. Anisakis is a herring worm. It is a round worm that is carried and transmitted by salt water fishes such as flounder,cod,haddock, yellow tail ( hamachi) and ling (a type of cod). It happens when the large fish eats the little fishes. When anisakis is swallowed it results in a disease called anisakis. This will make your stomach chum. Sometimes when ingested, and before it reaches your stomack, the worm will tickle your throat prompting you to cough it out or vomit the worm, if you are lucky. Anisakis can bore in your stomack or gut lining causing mild to severe abdominal pain and inflammation, often within an hour of eating the worm. The only way to get rid of the worm out of your body is by endoscopy or surgery . In addition, it can also cause mild to severe allergic reaction to some people. There is no cure for anisakis. The larvae can travel to the muscle tissue in the body. In severe cases of anisakis infestation, the body’s (WBC) white blood corpuscles will gather around the worm to fight off the infection and form a mass or granuloma often misdiagnosed as a tumor.
Anisakis is visible to the naked eye as a whitish thread or fleck in the fish tissue and should not be confused by the veins and sineus that they resemble. If the flesh of the fish looks mealy,it is a sign that it may be infested with the anisakis worm. Segments of the fish tissue that may indicate the prescense of tapeworm larvae is a whitish cyst in the fleshy tissue. If this is the case, inform the sushi chef if you are eating in a sushi bar about it and stop eating from that sushi bar. Chances are they are not buying quality fish product . If you like to make your own, make sure you know where to purchase safe fish for sushi. Since your health is at stake, the rule is not to buy cheap fish to make sushi, but rather, buy the best and safest fish to make sushi. Keep it on ice on your way home and until you prepare and eat it. If you have freshly caught fish, gut it immediately after you catch it, but do not eat it raw. Icing does not kill the anisakis and tapeworm larvae. This fish is best cooked and well done.
Tape worm can be cured by a drug known as Yomesan,a drug classified as niclosamide and legally available only from CDC (Center for Disease Control) . According to Sandy Fork,Director of the Parasitic Disease Drug, the number of request for Yomesan has increase from 41 in 1968 to 3,414 in 1980. Request for the drug came mainly from eating raw fishes by American travelers returning from various parts of the world and to the South East Asian refuges who arrived in the the US with tapeworm.
If you like to go fishing and enjoy eating raw fish, gut your fish immediately after you catch it and before freezing . This will reduce anisakis and tapeworm infestation. Marinating the fish will not kill the larvae, freezing following FDA mandate will, but will diminish the taste. Commercial fishing vessels that catch fishes for the Japanese market guard there investment by equiping their vessels with a blast freezer to immediately blast freeze the fish they catch, and a holding freezer to hold the blast frozen fishes to -10 deg F until they reach shore and unto the fish market for the big auction.
Inspite of the risk that one encounters when eating raw fish, affecionados continue to eat sushi and sashimi . In the US, sushi and shashimi eating use to be limited to the highbrow. Lately sushi bars are now found everywhere and sushi and shashimi are consumed by people of all level of income.
Be careful when eating raw fish!