
Originally Posted by
Doc Alan
There are more than 100 parasitic worm (helminth) infections of humans. 1 billion people, give or take a few million, are hosts to nematodes (roundworms). Many live with us quite peacefully, others cause bowel problems and anaemia. Trematodes (flatworms, flukes) are also common - schistosomiasis affects 10% of the population in the tropics and middle east, and cause bladder, bowel, or liver disease. Filarial infection causes "river blindness" in several million people, especially Africa and South America. Cestodes (tapeworms) first affect the gut and may or may not cause serious disease. Threadworms deserve their own thread !
Worms are certainly not vital to human health - at best we can co-exist with them and at worst they cause serious disease or death.