Doctors are warning the 1million Americans who visit Thailand every year to avoid a local dish dubbed ‘the world’s deadliest meal.’
Koi pla is made of raw fish ground with spices and lime and ‘just one mouthful’ is enough to cause cancer.
The freshwater fish it is made from are at high risk of being contaminated with parasitic worms known as liver fluke.
Once in the body, these microscopic parasites cause inflammation that damages cells and leads to cholangiocarcinoma (CCA) bile duct cancer.
Boston-based food policy expert and Northeastern University professor, Dr Darin Detwiler, told DailyMail.com: ‘If the fish is harboring the parasite, any consumption of the raw meat can introduce the parasite into the body, leading to infection.
‘It just takes one mouthful.’
Koi pla, made of raw fish ground with spices and lime, is a favourite feast for parasites responsible for deadly liver cancer, doctors warn
Over past decades, there have been extensive efforts to build awareness around the link to raw fish in a bid to curb rates.
Other meals made from raw fish, such as pla som, pla jom and pla ra, can also trigger cancer, as they contain the same species of fish as koi pla.
But despite warnings, a 2023 study found that these dishes are still popular in the northeast part of Thailand, which thankfully is less touristy than the south.
The research, led by Yi-Chen Wang from the National University of Singapore, took surveys in three sub-districts – Ban Kaengt, Na Tan, and Non Phayom – across three provinces in the area.
A total of 820 questionnaires were obtained, with 66 percent of respondents confirming that they eat raw fish despite knowing about the risks.
Close to 70 percent of the participants held the correct understanding that eating raw fish could lead to parasitic infection.
More than a quarter of the participants (28.3 percent) incorrectly believed that other raw foods, such as raw shrimp, raw beef, vegetable and fruit, were also the sources of liver fluke infection.
One of the major causes of bile duct cancer, which kills 20,000 Thais each year, is a parasitic flatworm native to the Mekong region and found in freshwater fish
When quizzed about the best methods to kill the parasite, 10 percent of respondents incorrectly believed that it could be killed by adding other ingredients, such as vinegar, lime juice, alcohol, or red ants.
The best way of killing liver fluke is to thoroughly cook the fish before consuming it.
Fish liver flukes are killed at an internal temperature of at least 145°F or you can freeze fish at -4°F for below for at least seven days.
For consumers in regions outside Thailand, where raw freshwater fish is less common, the risk is much lower, but Dr. Detwiler told DailyMail.com that it still exists with improper food handling.
He said on the matter: ‘This specific parasite (opisthorchis viverrini) is not common in the US.
‘However, foodborne parasites from raw or undercooked fish are still a risk, including tapeworms and other flukes.
‘The parasite that leads to liver cancer in Thailand is predominantly found in Southeast Asia, particularly in regions where raw freshwater fish dishes are popular.
The best way of killing liver fluke (pictured) is to thoroughly cook the fish before consuming it, or by freezing it
‘Cases of opisthorchis viverrini infection have been reported in the US – but they are rare.
‘Infections in the US are typically “imported cases,” meaning the individuals acquired the infection abroad and then developed symptoms later.
‘Cases are generally linked to individuals who have immigrated from or traveled to regions where the parasite is endemic, such as Southeast Asia.
‘Specifically, the majority of these cases have been observed among refugees from Vietnam, Laos, Cambodia, and Thailand, particularly in communities where the consumption of raw or undercooked freshwater fish is common.’
Outside of Thailand, koi pla is not a popular dish and it is very rarely found on restaurant menus.
The recent study calls for greater education around liver fluke and its prevalence in raw fish.
It also highlights the need for effective disease control programs, and the researchers noticed that a resurgence of infection was common, once a program ceased.
They add: ‘The success of a national health control program [in Thailand] greatly depends on community support to implement educational campaigns, promote public awareness, and facilitate individual behavior change.’
