Worms in Asian Fish Tied to Liver Cancer
Pastor Dale Morgan
Worms in Asian Fish Tied to Liver Cancer*
By MARGIE MASON
The Associated Press
Thursday, July 12, 2007; 2:38 PM
HANOI, Vietnam -- Worms found in freshwater fish in Southeast Asia can
lead to a rare type of liver cancer in people who eat raw fish, with one
province in Thailand logging the world's highest rate of new cases, a
study found.
An estimated 6 million people are infected with the parasite in
Thailand. High rates also have been observed in neighboring Laos, where
a traditional dish is made from raw fish, according to the study in the
online journal PLoS Medicine.
The worm, endemic in the Mekong River countries of Thailand, Laos,
Vietnam and Cambodia, is ingested through the fish and attaches to the
liver. Over several decades, the infection can create ulcers and
inflammation leading to tumors and cholangiocarcinoma, or cancer of the
bile ducts. Most patients typically develop cancer in their 40s or 50s.
"It is quite slow growing. But when it turns out to be cancer, it is
very rapid," said lead author Banchob Sripa of Khon Kaen University's
Pathology Department in Thailand. "If you start out getting diagnosed
today, maybe in the next six months you will die."
The disease is rare, making up less than 1 percent of all cancers
worldwide in 2002. But it is much more common in Khon Kaen province,
where liver cancer strikes nearly one in 1,000 men _ nearly all cases
bile duct cancer. Women are three times less likely to develop the
disease, Banchob said.
Koi-pla, the Thai name for a dish of minced raw fish mixed with hot
chilies and local spices, is a staple in Khon Kaen. The fish are
typically caught in rivers or ponds that are often contaminated by
untreated sewage.
The worm can be eliminated from humans with praziquantel, a drug that is
cheap and easily available. But another recent study showed that even
though about half of those surveyed in Khon Kaen province had taken the
pill at some point, the parasite was still present in about 30 percent,
said Banchob.
In southern Laos, where people share the same culture and ethnic
background as those in northeastern Thailand, villagers eat a similar
raw fish dish and liver parasite infection is also a problem.
"It would be good to make them change their habits and attitudes in
terms of eating raw, but it's very difficult," said Peter Odermatt of
the Basel-based Swiss Tropical Institute, who has also done research on
the parasite but did not participate in this study.
Little research has been conducted in Cambodia and Vietnam on the
parasite, but raw fish dishes typically are not as popular in those
countries.
Asia is home to about three-quarters of the world's liver cancers,
caused largely by hepatitis B infections.
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On the Net:
PLos Medicine: http://medicine.plosjournals.org