I'm am not lame like derrick
1. Roundworms are parasites.
2. They are common in many species and each species has a roundworm that is specific to them including humans. There are thousands of different types of roundworms.
3. Because each worm can produce thousands of eggs per day, the environment can be contaminated with millions of eggs over a short period of time. The eggs can survive for months or even years in the environment.
4. Elephantiasis is a type of roundworm we can 'catch' from mosquitoes.
5. Hookworms which are a type of roundworm cause a really itchy skin condition
With thousands of roundworms there's plenty of info but I'm playing by the rules :-).