Heavy parasitic loads can cause stress and suppress the immune system - opening the door to a wide variety of infectious bacteria. Heavy infections can also affect the fertility level of eggs and thus reproduction. The worms reproduce in the host, and the eggs are excreted in the feces. Most occur in the intestine and stomach though some larva can migrate into the lungs and throat. Those most commonly found are 'roundworms' which have an indirect life cycle.
Hookworms have a direct life cycle and huge loads can build up in the system in a very short time.
Pinworms also have a direct life cycle and commonly cause an obstruction in the intestinal canal. Strongyloides have a direct life cycle, and these can cause severe diarrhoea, mucous in droppings, and sometimes respiratory distress owing to larva invading the lungs. The responsible tortoise keeper should have droppings from animals in his care checked twice yearly. This test is simple and can be performed by any veterinarian or competent animal keeper with a microscope. Certainly, before any tortoise is added to your collection it should be tested for parasites repeatedly during the quarantine period.