opisthorchióza

Opisthorchiasis is a food-borne parasitic disease caused by liver flukes of the genus Opisthorchis, primarily Opisthorchis viverrini and Opisthorchis felineus. These flatworms reside in the bile ducts of the liver and gallbladder of humans and other fish-eating mammals. Transmission occurs when humans consume raw or undercooked freshwater fish that contain the infective larval stage, known as metacercariae.

The life cycle involves freshwater snails as the first intermediate host and freshwater fish as the second intermediate host. After ingestion by humans, the metacercariae excyst in the duodenum and migrate to the bile ducts where they mature into adult worms. These adult worms can live for many years, feeding on bile and blood.

The severity of opisthorchiasis depends on the parasite load and duration of infection. Mild infections may be asymptomatic. However, chronic infections can lead to inflammation and damage of the bile ducts, a condition known as opisthorchialiasis. Symptoms can include abdominal pain, indigestion, fatigue, jaundice, and liver enlargement. Long-term complications can include liver fibrosis, gallstones, and cholangiocarcinoma, a type of bile duct cancer.

Diagnosis is typically made by microscopic examination of stool samples for the characteristic operculated eggs of Opisthorchis. Serological tests are also available. Praziquantel is the drug of choice for treatment. Prevention focuses on thorough cooking of freshwater fish to kill the parasitic larvae. Public health interventions aim to raise awareness about the risks associated with consuming raw fish in endemic areas. Opisthorchiasis is endemic in parts of Southeast Asia, particularly Thailand, Laos, Vietnam, and Cambodia, as well as some regions of Eastern Europe and Siberia.