Parasitic worms are every where in nature. The two most common types are Flatworms and Roundworms

Flatworms

Tapeworms, hookworms and blood flukes are all examples of flat worms.

The tapeworm is one of the most common types of flatworms. They are an endo-parasite which inhabit the guts of animals.

Their head attaches to the wall of the gut. The neck area is the growth area. They can often grown up to 10 meters long. They grown in segments which contain male and female reproductive organs. Each segment matures into a sac of eggs, which breaks of and is excreted via faeces.

Liver flukes also live within various organisms. In its larval stage, it lives within a snail, it then progresses to an ant and finally into a herbivore.

The liver fluke, is capable of brain washing the ants into presenting themselves to approaching herbivores. For more information click here.

Round worms/Nematodes

Nematodes or Roundworms, are present in large numbers in the environment. Although there are both free-living and parasitic nematodes ranging in size (from microscopic to 20 cm) their basic body structure is very similar.

Elephantiasis is caused by a nematode from the Wuchereria bancrofti species. Its causes extreme swelling in body parts (as seen in the image).

This parasite is carried via mosquitoes in its larvae form, and gradually matures. Once the mosquito bites an animal, the parasite burrows into the skin near the bite. It travels in the lymph and matures into an adult.

The parasites multiple and block the flow of lymph, causing massive swelling.

Pinworms are a form of nematodes which live within the intestines of humans. You can become infected by them by inhaling or swallowing their eggs.  

Female pinworms exit the anus at night to lay their eggs, and then re-enter.

The video to the right is a colonoscopy of an individual infected with nematodes.