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Liver Flukes: Everything You Need to Know About This Cancer-Causing Parasite

Liver Flukes: Everything You Need to Know About This Cancer-Causing Parasite

One may not typically associate parasitic worms with cancer, but the link between liver flukes and bile duct cancer, also known as cholangiocarcinoma (CCA), is becoming increasingly clear. Though rare, CCA is particularly concerning for military personnel and veterans who served in Southeast Asia, where liver fluke infection is a major risk factor for CCA. The rise in cases among veterans signals a need for urgent attention and increased awareness of this health issue.

What Is A Liver Fluke?

Liver flukes are parasitic flatworms that mainly infest the bile ducts in the liver. The infection, known as liver fluke disease, occurs primarily through consuming raw or undercooked fish, a common practice in several Asian countries. 

What Do Liver Flukes Look Like?

Liver flukes are flat, leaf-shaped parasitic worms typically a few centimeters long. The most common species that infect humans are Clonorchis sinensis, Fasciola hepatica, and Opisthorchis viverrini.

Here’s a general description:

  1. Clonorchis sinensis, also known as the Chinese liver fluke, is a small liver fluke with a length typically around 15-20 mm (0.39-0.98 in). Its body is elongated and flat, with an oral sucker at the anterior end, around which the body curves. It is also estimated to be the world’s third most prevalent parasitic worm.
  2. Fasciola hepatica, or the common liver fluke, is much larger than Clonorchis sinensis, typically measuring 30mm (~1 in) long and up to 13mm(~0.5 in) wide. It has an oval shape, and its body is covered in a rough, spine-covered cuticle. This species is more common in livestock but can also infect humans.
  3. Opisthorchis viverrini, the Southeast Asian liver fluke, is small, typically around 7 mm (0.27 in) long. Like the Chinese liver fluke, it has an elongated, flat body and an oral sucker. This liver fluke species is the most prominent in Thailand, Laos, Vietnam, and Cambodia.

The actual color, shape, and size of liver flukes can vary somewhat between individual flukes and different life cycle stages. For example, younger flukes (larval stage) are much smaller than the adults, and the eggs are microscopic and thus not visible to the naked eye.

Infections and Illness

The infection liver flukes cause is known as liver fluke disease or fascioliasis. It can cause serious damage to the liver and bile ducts and requires medical attention.

Upon entering the human body, liver flukes inhabit the bile ducts and begin to feed on the cells of the bile duct lining, causing chronic inflammation and irritation. The symptoms of liver fluke infection can range from mild, including abdominal pain and jaundice, to severe. However, its long-term implications are even more threatening. 

Chronic liver fluke infection can progress to bile duct cancer, or cholangiocarcinoma, a rare but highly lethal form of cancer. As the body constantly tries to heal and replace these damaged cells, it can inadvertently increase the risk of errors in cell replication, potentially leading to cancerous changes, a process known as oncogenesis.

In addition, the chronic inflammation triggered by the liver flukes can stimulate the production of reactive oxygen species and other inflammatory substances, which can cause DNA damage and contribute to the development of cholangiocarcinoma, a type of bile duct cancer. 

Symptoms of Bile Duct Cancer

Bile duct cancer may not cause symptoms in its early stages. As it progresses, however, symptoms can begin to appear. Common symptoms include:

  1. Jaundice: This is often one of the first symptoms. It is characterized by yellowing of the skin and whites of the eyes and dark urine. 
  2. Abdominal pain: Particularly in the upper right portion of the abdomen or in the center of the abdomen. The pain may be dull rather than sharp.
  3. Weight loss: This may be unexplained and progressive.
  4. Itching: Excessive itching, or pruritus, is often mistaken as an allergic reaction and treated as such.
  5. Fever: A person might experience fevers.
  6. Changes in stool or urine color: Stools may be light-colored or gray, and urine may be darker than usual.
  7. Nausea and vomiting: These symptoms can be associated with a wide range of conditions and diseases, but combined with the above symptoms, it could indicate bile duct cancer.

These symptoms may be misdiagnosed because of the rarity of bile duct cancer. Medical professionals may even assume the cause is something else, such as hepatitis, gallstones, or other liver and biliary diseases. If you or someone else has these symptoms, especially if they’re persistent or worsening, it’s important for veterans to see a healthcare professional for an accurate diagnosis. Providing information, such as where you were stationed, can help a doctor give a proper diagnosis. 

The sneaky nature of this cancer means that symptoms often remain subtle until it has advanced, making treatment increasingly difficult. Like all cancers, early detection of bile duct cancer can improve the chances of successful treatment. Veterans, especially those who served in regions where liver flukes are endemic, need to be informed about their risk and urged to undergo regular screenings.

An Overlooked Risk Among Vietnam Veterans

In addition to liver fluke exposure, Vietnam Veterans were also exposed to dioxin, an Agent Orange ingredient that has been linked to many other types of cancer. CCA may not be detected until several decades after a veteran leaves service, making it difficult to establish a service connection. 

Though there are commonalities between veterans diagnosed with CCA, the rare nature of this cancer makes it more difficult to establish a direct causal relationship. The VA’s current stance is that no definitive proof links liver fluke infection with cancer. Because of this, bile duct cancer is not on the presumptive illnesses list. Filing a claim will require much more work on the veteran’s end to prove that an in-service event caused their condition. 

The link between liver flukes and cancer serves as a potent reminder of the long-lasting health impacts of military service. 

Reach Out to An Experienced VA Attorney

If you feel you’ve been wrongly denied for your claim, partner with an experienced attorney to file your appeal. Schedule a free consultation with Cameron Firm, PC by calling (800) 861-7262 or submitting a form. Use our experience and resources to get the benefits you deserve.

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