Complex sentence: Elephantiasis is caused by chronic infection by filarial worms in the lymph nodes which clogs the lymph nodes and slows the draining of lymph fluid from a portion of the body.
Split into simpler sentences: Elephantiasis is caused by chronic infection by filarial worms in the lymph nodes. This clogs the lymph nodes and slows the draining of lymph fluid from a portion of the body.