What are the main phases
and clinical manifestations of
schistosomiasis?
Schistosomiasis is an infectious disease that is acquired when people come in contact with fresh water containing infectious larval forms, cercariae of blood flukes that live as a parasite in our body. These blood flukes are called schistosomes. The adult form of these worms lives in veins and intake host nutrition from urinary tract and intestine.
There are three main stages of schistosomiasis, early-stage, intermediate and chronic stage.
Early-stage: In this stage, cercariae which is the larval stage of a fluke, enters the skin and results in hypersensitivity and skin rashes.
Intermediate stage: In this stage, the organism after penetrating in the body, enters the bloodstream and migrates to the lungs, then to heart and finally reaches the liver where it matures. After 4 to 8 weeks of exposure, acute illness occurs along with fever, cough, diarrhoea, and eosinophilia. In cases of severe acute infection due to Schistosoma mansoni, diarrhoea accompanied by blood appears.
Chronic schistosomiasis: In chronic infection, the retained eggs in the body cause the production of eosinophilic granulomas, scarring and fibrosis. The extent of infection depends upon the worm load in the person's body. A low worm load may not cause any symptom, but an obstruction to blood flow can be seen.
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