The most common internal parasites in pets that can be transmitted to people are roundworms, tapeworms and hookworms. Children in particular are more at risk because they are not always careful of hygiene. Soil or sandboxes can become contaminated with fecal matter. Children become infected by playing in contaminated sand or dirt and then putting their hands or contaminated objects in their mouths. Hookworm larvae can also penetrate the skin.
Internal parasite eggs and larvae are virtually everywhere in the environment and can survive in the soil for years waiting to infect pets or people. Some species thrive in warm climates while others proliferate in colder regions. This is why routine deworming and preventive steps are so important.