In the province of Kalasin, villagers wait in line to be screened for a cancer-causing parasite. They were singled out as having high-risk factors—particularly those aged 40 and above, with a history of eating raw fish, and had family members with liver cancer.

Most of these come from one of the poorest provinces in northeast Isaan region where koi pla, a relatively cheap and tasty raw fish dish has become a signature dish in their lunch menu. The region is reported to have a high incidence of the cholangiocarcinoma (CCA) — bile duct cancer — in the world.

While a third of those screened showed abnormal liver symptoms and four were suspected to have cancer, 48-year-old Thanin Wongseeda is one of the lucky ones screened negative for the liver fluke.

“I’ve never been checked before, so I think I will probably have it because I’ve been eating (koi pla) since I was little,” said Thanin, expressing relief.

But for Dr Narong Khuntikeo’s parents, the dish was lethal. Made of raw fish flavoured with spices and lime, it was a regular meal for his parents as well as many Thais across the rural region.

Witnessing the tragic death of his parents in the hands of the fluke, and seeing scores of hopeless late-stage patients lying in the operating theatre, Dr Narong, a liver surgeon, is tasked on a mission – to track the ‘silent killer’. He has mobilised scientists, doctors and anthropologists in an initiative, called CASCAP (Cholangiocarcinoma Screening and Care Program), which started as research at Khon Kaen university and is now on the country’s national agenda.

Over the past four years, his team has trucked ultrasound machines across the Isaan provinces to examine the livers of villagers, who otherwise would not have access to public hospitals, and to warn them of consuming the carcinogenic koi pla and other risky fermented fish dishes. They have also developed urine tests to detect the presence of the parasite.

Parasite has infected up to 80% of Isaan communities

The parasitic flatworm or fluke, native to the Mekong region and found in many freshwater fish, is identified as one of the major causes of CCA. Without surgery, the disease has one of the lowest survival rates of all cancers, according to cholangiocarcinoma charities, and is said to kill 20,000 Thais annually.

According to the World Health Organisation (WHO), the worms, once eaten, can embed undetected in the bile ducts for years – causing inflammation that can, over time, trigger the aggressive cancer.

“It’s a very big health burden around here… It effects families, education and socioeconomic development,” said Dr Narong.

“But nobody knows about this because they die quietly, like leaves falling from a tree.”

Changing eating habits – pinning hopes on the younger ones

For Thanin, it is a wake-up call. “I don’t think I will eat (koi pla) raw anymore.” But as for his neighbours, he feels, “They will not quit it easily.”

Though many villagers expressed shock when they heard of the lethal effects of their favourite age-old dish, many are still reluctant to abandon the routine of whipping up an easy meal from fish caught in the ponds. After all, giving up a staple dish which has graced the menu for generations is always a challenge, more so for the older folks.

“I used to come here and just catch the fish in the pond… It’s so easy to eat raw,” expressed Boonliang Konghakot, a farmer from Khon Kaen province, licking his lips as he sprinkled seasonings into a bowl of the finely-chopped fish’s pink flesh.

But ever since he heard news of its carcinogenic potential, Boonliang has started frying the fish to kill off the parasite, which is also a method that doctors recommend.

However, many villagers claim cooking the pink flesh gives it a sour flavour. Meanwhile, there are others who seek solace in fate, believing that happenings are pre-destined – a common Buddhist belief embraced by a majority of the Thai population.

“They’ll say, ‘Oh well, there are many ways to die’,” lamented Dr Narong. “But I cannot accept this answer.”

Hence, for the elderly who are not likely to be swayed, the target is to catch infections – before the fish catches their lives.

The hope lies in the next generation as health officials are now targeting the younger population by incorporating healthy eating habits in the new school curriculum where cartoons are used to spin lessons on the risks of eating raw food. MIMS

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