There are multiple opportunities to detect tapeworm cysts and larvae before the sushi makes it to our plate. Epicurrence
Australians love their sushi and consume more than 115 million servings of seaweed-wrapped rolls and sashimi (slices of raw fish) per year.
But a story doing the rounds this week is enough to scare anyone off their raw salmon lunch. A Californian man presented to his local emergency department with abdominal cramps and bloody diarrhoea – caused by a 1.5-metre tapeworm. He seems to have contracted the parasite from raw sushi, which he ate most days.
Tapeworms are flat, segmented worms that live in the intestines of animals and humans.
The tapeworm the Californian man contracted was most likely fish tapeworm, or Diphyllobothrium latum. It is the longest tapeworm found in humans – it can reach 10 metres in length and live for up to 20 years.
The life cycle of the fish tapeworm is complex. Eggs from infected animals and humans are passed from faeces into water, where they hatch. This first stage of larvae is ingested by crustaceans.