Beware: US salmon may be crawling with Japanese tapeworm, say scientists


Image: Beware: US salmon may be crawling with Japanese tapeworm, say scientists

A recently published study in the journal Emerging Infectious Diseases says wild caught Alaskan salmon may harbor a species of tapeworm previously known to infect only Asian fish. Researchers warn that based on their findings, any salmon caught along the North American Pacific coast may have the parasite. The concern is that if you eat the fish undercooked or raw, you could become a host to this gruesome organism.

CNN reports that the tapeworm newly discovered in Alaskan salmon is named Diphyllobothrium nihonkaiense, also known as the Japanese broad tapeworm. This species accounts for the most infections in humans, in contradiction to the previous belief that the dubious distinction went to the most common fish tapeworm, Diphyllobothrium latum. A team of scientists found four species of Pacific salmon known to carry the Japanese tapeworm: chum salmon, masu salmon, pink salmon and sockeye salmon. These fish are caught and then shipped worldwide, so the infection may occur in humans anywhere on the planet. (RELATED: Stay informed about the health risks of food ingredients at

Tapeworms, including the Japanese version can grow to 30 feet inside a human digestive tract. Infestation often goes undetected, because symptoms may often be mild, with symptoms largely attributed to other conditions by medical practitioners. When fish are commercially caught worldwide, they are placed on ice for the journey to port. But this does not freeze the fish, it only refrigerates them. To kill the possibly present parasite worms, the fish need to be frozen. Salmon sushi at a restaurant or store can be assumed to be an unsafe commodity unless you know it has been frozen or you freeze it yourself. Additionally, the fish can be sufficiently cooked for assurance of safety against parasitic infection.

Get CLEAN FOOD and help support our mission to keep you informed: The Health Ranger Store lab verifies everything we sell with accredited testing for heavy metals, microbiology and food safety. Certified organic facility, ISO-accredited on-site laboratory, no GMOs or synthetic ingredients. The world’s #1 source of lab-verified clean foods and superfoods for nutritional healing. 600+ products available. Explore now.

Jayde Ferguson, a scientist at the Alaska Department of Fish and Game believes, “The tapeworm itself is probably not new — it’s just that more skilled parasitologist started looking for it. Identifying these parasites is challenging. This was simply a more detailed evaluation of the Diphyllobothrium that has occurred here for over a millennium.”

Professor of preventive medicine at Vanderbilt University School of Medicine Dr. William Schaffner stated, “Because we do things that we haven’t done before, now, we have these fresh caught fish that can be transported anywhere and eaten raw. … I am sure we will be on the lookout for this kind of tapeworm going forward.”

Parasitic worms – an under-recognized epidemic

Naturopath Marijah McCain is a widely experienced healer who apprenticed with a parasitologist and knows firsthand about these disgusting critters and how to rid the body of the menace. Though rare, various helminths (worms) such as the tapeworm can find a home in your brain with grave consequences. Quoting Marijah:

“Myself and a handful of others, like Dr. Hulda Clark, have spent years trying to bring the parasite issue to the forefront of preventative & curative medicine. The good news is the medical field is slowly training their doctors once again on the health risks of parasites… Most Americans carry parasites and this is currently a serious health issue. Parasites are not meant to kill you, they just sit inside you and steal your nutrition. But, when a person gets weakened from another ailment the parasites can take hold and become life threatening. This is why EVERYONE with any health disorder should do an anti-parasite program at least once a year. Twice a year if you live with animals. People interested in maintaining good health should also do routine parasite cleansing…”

Marijah says that symptoms caused by parasites include gas, diarrhea, chronic constipation, bloating, fatigue, skin rashes, mood swings, insomnia, nail biting, dry skin, weight gain, bad breath, brittle hair, hair loss, and muscle cramping. Because parasites can invade any tissue in the body, symptoms can occur anywhere. Dr. McCain states that parasites are a contributing factor in conditions such as Crohn’s disease, ulcerative colitis, diabetes, some heart disease, arthritis, asthma, as well as others. She points out that in the US, the medical system is in denial about the health risks of parasitic infections, and doctors make a huge blunder when they fail to recognize the role that parasites play in disease. “Parasites are the cause of hundreds of misdiagnosed ailments,” she claims, and recommends natural anti-parasite formulas in lieu of conventional toxic allopathic medications.

The tapeworm that turned into a tumour.

Bizarre case study reports how cancerous cells came from a tapeworm infection.

Eggs of the dwarf tapeworm (Hymenolepsi nana).

A tapeworm that infected a Colombian man deposited malignant cells inside his body that spread much like an aggressive cancer, researchers have reported in a bizarre, but not unprecedented, case.

“We have a situation where a foreign organism is developing as a tumour rather than developing as an organism,” says Peter Olson, a developmental parasitologist at the Natural History Museum in London. He is part of a team that describes the case in a 4 November report in the New England Journal of Medicine1.

The apparently cancerous cells were first examined in 2013 by investigators at the US Centers for Disease Control and Prevention (CDC) in Atlanta, Georgia. They came from a 41-year-old Colombian man with HIV, who had been ill for months when he sought medical attention in January 2013. Colombian doctors found that he had a compromised immune system, had been infected by the dwarf tapeworm (Hymenolepis nana), and had small tumour-like growths in his lungs and lymph nodes. They sent tissue samples to the CDC.

Under a microscope, those samples revealed small odd-shaped cells that, like a cancer, appeared to be invading nearby healthy tissue, the CDC team found. Yet the cells tested negative for human proteins. That was a conundrum: although the US investigators knew about the man’s tapeworm infection, the invading cells did not look like they should belong to a complex, multicellular organism such as a tapeworm.

Tragically, in May 2013, the patient experienced kidney failure and died. A team led by CDC pathologist Atis Muehlenbachs examined the DNA of the invading cells and determined that they did belong to a tapeworm. And genome sequencing showed that the tapeworm cells carried particular mutations that, in human cells, are associated with tumours.

Tumours from tapeworms

Tapeworm-derived tumours are extremely rare, says Olson, who has documented a handful of other cases in patients whose immune systems were compromised2, 3.

Olson believes that the tumorous tapeworm cells are rogue larvae that burrowed from the stomach into the lymph nodes of immunocompromised people (a healthy immune system would stop this invasion). The larvae are loaded with regenerative stem cells, so instead of turning into an adult tapeworm, they proliferate. “Those stem cells that would normally give rise to a segmented worm don’t, because they’re in the wrong place and have the wrong environmental cues,” says Olson.

Some of the cases that Olson has worked on involve the dwarf tapeworm, which is unique among the several thousand other known tapeworm species in that it can develop fully in the gut of its mammalian host. Normally, tapeworm eggs are expelled by their host and then mature in an invertebrate, before being transmitted back to a vertebrate host.

Elizabeth Murchison, a molecular geneticist at the University of Cambridge, UK, says that she finds the case astonishing. Although there is no evidence that the proliferative tapeworm cells might be transmitted between humans, Murchison (who studies tumour cells that spread between animals) wonders whether proliferative cells from other parasites could become infectious.

“This paper is tremendously important as it presents the existence of a new type of disease process, which may have previously been overlooked,” she says.

A man has contracted cancer from a tapeworm for the first time ever.

A 41-year-old Colombian man was given cancerous tumours by a tapeworm living inside him, doctors have discovered – the first known report of someone becoming ill from cancer passed on by a parasite. Scientific American reports that the man eventually died from complications relating to HIV, and the weakening of his immune system caused by HIV was likely to be a factor in allowing the tapeworm cancer to spread.

At first, the tumours baffled local doctors: the growths exhibited some of the characteristics of cancer cells, but they were 10 times smaller than the cells you would expect to find in a human and packed very closely together. They turned to the US Centres for Disease Control and Prevention (CDC) for help and it was then that the link to a tapeworm was discovered.

“In the initial months, we wondered if this was a weird human cancer or some unusual, bizarre emerging protozoa-amoeba-like infection,” the CDC’s Atis Muehlenbachs told the Washington Post in an interview. “Discovering these cells had tapeworm DNA was a big surprise – a really big surprise… this is the first time we’ve seen parasite-derived cancer cells spreading within an individual. This is a very unusual, very unique illness.”

Here’s what researchers at the CDC think happened: the Colombian man initially ingested some microscopic tapeworm eggs, probably from food that had been contaminated by mouse droppings, insects or human faeces. Those eggs then multiplied rapidly in the gastrointestinal tract because the man’s immune system had already been compromised by the HIV infection – the cells then spread to other parts of the body.

What’s not clear is whether the cells were already cancerous or whether some kind of biological reaction caused them to develop into tumours. In fact, ‘cancer’ may not even be the correct word here, because this is so different from what we normally use the term for: Muehlenbachs says “an infection with parasite-derived cancer which causes a cancer-like illness” may be the more appropriate (though much more verbose) term.

“Can you say a worm has cancer? That’s a philosophical question how you define this,” he adds.

However scientists end up defining this newly discovered condition, it has some important things to teach us about cancerous cells: up until now, it wasn’t thought possible for parasites to develop cancer, let alone pass them on to humans. What’s more, cancer isn’t considered a transmissible disease, though a few such cases among dogs and Tasmanian Devils have previously been recorded.

The death of this Colombian man has put some of those theories into doubt, and scientists are now calling for more to be done to diagnose the disease and collect data about it in developing nations – if there are more cases like this, we should be able to understand how it is being caused.

%d bloggers like this: