Some of its main cause of worms -
1. Eating of contaminated food which results into roundworms. Like this thread worms enter our body from dirty food and fingers.
2. When any person walks on infected earth with bare foot then there are chances that the hook worm may enter our body. Like this tapeworms are transmitted into our body through foods contaminated by dogs and also through undercooked flesh foods.
3. Sometimes the faulty living style may also cause intestinal worms.