From: Anchorage Dispatch News

Tapeworm from Asian waters identified in Southcentral Alaska salmon

Scientists have found a parasite from Asian salmon in North American fish, according to a newly released study on samples taken from Southcentral Alaska conducted with help from state officials.

The study, appearing in February’s issue of the journal Emerging Infectious Diseases published by the U.S. Centers for Disease Control and Prevention, reports on the discovery of Japanese broad tapeworm in Alaska salmon. Its authors say the results could mean Japanese broad tapeworms infecting humans have been mistaken for fish tapeworm, a species known by the CDC to affect North American fish. …

The authors of the study, conducted with support from the Czech Science Foundation, examined 64 Alaska-caught wild salmon in July 2013, including 31 sockeyes, 23 pinks, eight rainbow trout and one each of king and coho salmon. Several tapeworms were found, including one larva taken from a pink salmon caught in Resurrection Creek near Hope that was a 99 percent match for Japanese broad tapeworm based on a genetic database. …

Ferguson said Alaska fish already carry several species of tapeworm — creatures with a “complex life cycle,” beginning when tapeworm-infected birds and mammals excrete tapeworm eggs into water. Those eggs produce larvae, which are then eaten by and infect small crustaceans known as copepods; fish are infected when they eat those copepods, and mammals acquire tapeworms by eating infected fish. …

“There’s just more and more evidence of this worm infecting people outside of Asia,” Ferguson said. “This worm has always been here, and we’re just getting better at identifying it.”

Ferguson echoed DEC’s view regarding the study Thursday, saying there’s no significant difference between Japanese broad tapeworm and fish tapeworm. He also noted that nothing in the study merited a public warning about Alaska salmon during its gradual peer review process. …

Fish and Game has posted an online booklet about fish diseases, which recommends cooking fish to at least 140 degrees Fahrenheit for at least five minutes or freezing it to 4 degrees below zero for at least 60 hours to kill any parasitic worms. Tapeworms are covered on pages 60 and 61.

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