schistosomóza

Schistosomóza, also known as snail fever or bilharzia, is a parasitic disease caused by flatworms of the genus Schistosoma. These parasites infect people through skin contact with contaminated freshwater in which certain types of freshwater snails that harbor the larval forms of the parasite live.

The life cycle of the Schistosoma parasite is complex, involving both freshwater snails and humans. Adult worms live in blood vessels of the body. Females lay eggs, and some of these eggs are passed out of the body in urine or feces, contaminating water. If the eggs reach water, they hatch into tiny free-swimming larvae called miracidia, which then infect freshwater snails. Inside the snail, the parasite undergoes further development, and eventually, a different larval form, cercariae, is released into the water. These cercariae can penetrate the skin of humans who enter the water, starting a new infection.

Symptoms of schistosomóza vary depending on the species of Schistosoma involved and the duration of the infection. Acute schistosomóza can manifest as fever, chills, muscle aches, and a rash. Chronic schistosomóza can lead to a range of health problems affecting organs such as the liver, intestines, lungs, and bladder. For example, intestinal schistosomóza can cause abdominal pain, diarrhea, and blood in the stool, while urinary schistosomóza can result in blood in the urine, painful urination, and increased risk of bladder cancer.

Diagnosis typically involves identifying parasite eggs in urine or stool samples. Treatment is usually with antiparasitic drugs, most commonly praziquantel. Prevention strategies include avoiding contact with contaminated freshwater, improving sanitation and access to clean water, and targeted drug administration programs in endemic areas.