A tropical parasite may be slowly killing hundreds of U.S. veterans of the Vietnam War.
Early this year, the Department of Veterans Affairs commissioned a small pilot study to investigate the link between liver flukes ingested through raw or undercooked fish and a rare bile duct cancer called cholangiocarcinoma, the Associated Press reported.
Symptoms can take decades to appear and by the time they do, many patients are in extreme pain and only a few months to live.
"It was surprising," said Sung-Tae Hong, the tropical medicine specialist who conducted the tests at Seoul National University in South Korea.
He noted that these are preliminary findings that could include false positives and that the research is continuing, the AP reported.
The blood samples were collected at the Northport VA Medical Center in New York. Everyone who tested positive was notified, said center spokesman Christopher Goodman.
The parasites are rarely found in Americans, but infect an estimated 25 million people worldwide. Early treatment with medication kills the parasites. Left untreated, the parasites can survive for decades in a person without causing any symptoms.
Last year, the AP reported that about 700 veterans with cholangiocarcinoma have been seen by the VA in the past 15 years.
A warning posted on the VA website this year says veterans who ate raw or undercooked freshwater fish while in Vietnam might be at risk. But it did not advise them to get tested because there is currently no evidence that Vietnam vets had higher infection rates than the general population, the AP reported.
"We are taking this seriously," said Curt Cashour, a spokesman with the Department of Veterans Affairs. "But until further research, a recommendation cannot be made either way."