TOKYO, May 12 (Xinhua) -- Rising numbers of people are being infected with a parasitic worm known as anisakis after eating seafood that hasn't been frozen or heated properly, local media reported Friday.
Reported cases of anisakis infection surged to 124 in 2016 from six in 2007, according to figures from the health ministry, with the results leading to the ministry urging consumers to heat or freeze properly seafood before consuming it and to carry out visual inspections for the existence of the parasitic worm.
The worm itself can grow to be as long as 2 to 3 cm long, the ministry said. Its larvae infect the intestines of such fish as mackerel, bonito, salmon, squid and saury, before moving into the fish's muscles when they die.
The affects of anisakis infection can manifest as acute abdominal pain as anisakis invades the host's digestive system.
But the larva die when cooked properly or frozen for more than a day at minus 20 degrees Celsius, the health ministry said.
A spokesperson from the the National Institute of Infectious Diseases said that an increase in raw seafood being transported across Japan rather than being transported in a frozen state, was likely the cause of the spike in cases of anisakis infection.
The spokesperson said that around 7,000 people were likely being infected with anisakis a year, based on medical bills examined from between 2005 and 2011.
