Characteristics

• Most nematodes are less than 0.2 mm long and lay thousands upon thousands of eggs once they find a suitable host. Common nematodes that affect humans include pinworms and hookworms.
  
  

Transmission

• Nematodes can be transmitted to humans via water, soil or other hosts called "transfer hosts," according to the Center for Disease Control. Nematodes frequently infect aquatic creatures and are transmitted to humans via consumption or handling of water-dwelling creatures and drinking of infested water.
  
  

Dangers

• Nematodes can cause internal problems with humans and other mammals that include urinary and intestinal problems from rapid reproduction. Some nematodes affect the cardiovascular system and literally consume the cardiac tissue.
  
  

Prevention

• Regular testing and cleaning of drinking water and freshwater sources can limit the number of nematodes transmitted to humans. Vaccinate all pets that go outside as they can transmit soil and waterborne nematodes to you.