A half a century after serving in Vietnam, hundreds of veterans have a new reason to believe they may be dying from a silent bullet—test results show some men may have been infected by a slow-killing parasite while fighting in the jungles of Southeast Asia. The Department of Veterans Affairs this spring commissioned a small pilot study to look into the link between liver flukes ingested through raw or undercooked fish and a rare bile duct cancer, per the AP. It can take decades for symptoms to appear. By then, patients are often in tremendous pain, with just a few months to live. Of the 50 blood samples submitted, more than 20% came back positive or bordering positive for liver fluke antibodies, said Sung-Tae Hong, the tropical medicine specialist who carried out the tests at Seoul National University in South Korea.
"It was surprising," he said, stressing the preliminary results could include false positives and that the research is ongoing. Though rarely found in Americans, the parasites infect an estimated 25 million people worldwide. Endemic in the rivers of Vietnam, the worms can easily be wiped out with a handful of pills early on, but left untreated they can live for decades without making their hosts sick. Over time, swelling and inflammation of the bile duct can lead to cancer. Jaundice, itchy skin, weight loss, and other symptoms appear only when the disease is in its final stages. The VA study, along with a call by Sen. Chuck Schumer for broader research into liver flukes and vets stricken with the cancer known as cholangiocarcinoma, began after the AP raised the issue last year. About 700 veterans with cholangiocarcinoma have been seen by the VA in the past 15 years.