True or False: Schistosomes invade tissue.

Schistosomes, a type of trematode (flatworm), are known for their ability to invade tissues in their host organisms. The adult forms of schistosomes reside in blood vessels, particularly the mesenteric veins or the venous system around the bladder, depending on the species. As they mature and migrate through the host, schistosomes can cause significant tissue damage and inflammation.

This invasive behavior is a crucial part of their life cycle and pathogenicity. The eggs produced by these worms can lodge in tissues, leading to granulomatous reactions and eventual fibrosis in affected organs. The disruption they cause directly results from their tissue invasion, confirming that the statement is true.

Other options suggest varying circumstances under which tissue invasion might occur, but schistosomes are generally recognized for their capability to invade tissues consistently throughout their life cycle, not limited to certain stages or severity of conditions. This consistent ability to invade and affect host tissues underscores the importance of understanding schistosomiasis and its public health implications.