Roundworms, also called nematodes, come in many varieties and cause a variety of illnesses. Children, because of their occasional unsanitary behaviors, develop roundworm infections more often than adults. Some of the most common roundworms include hookworms, pinworms and whipworms. Around 14 percent of Americans have some type of roundworm infection, reports the Centers for Disease Control and Prevention, or CDC. Up to 33 percent of all children in some locations have a pinworm infection, according to the Cleveland Clinic.
Ingesting Feces
Toxocariasis is a roundworm infection caused by worms that infect the intestinal tracts of dogs and cats. The animal passes larvae, which are the immature forms of the worm, in the stool. Children who touch feces in the dirt and then put their hands to their mouths may ingest the larvae. Larvae may travel through the body rather than staying in the intestines, damaging tissues and nerves and, in rare cases, lodging in the eye and causing vision loss. Fever, cough, asthma or pneumonia may also occur, the CDC states. Ascariasis, transmitted by human feces in the soil, may be ingested by children who touch contaminated soil. Cough, abdominal pain, nausea, blood in the stool, weight loss and fatigue may occur.
Contaminated Bare Feet
Hookworms are passed through human feces in areas where people defecate or throw human waste onto the ground. The larvae can move from a cooler area to a more moist area once they grow to an infective stage. Hookworm larvae can pass through bare skin on the feet if a child steps on them, causing an allergic-type rash known as ground itch. Larvae enter the lungs through the bloodstream, traveling up the windpipe. The child then swallows them and they enter the intestine. Diarrhea, abdominal pain, cramps and nausea occur. Children can develop anemia from a heavy infection with hookworms, which attach to the intestine to feed, the Cleveland Clinic warns. Around 25 percent of the world's population has hookworms, according to the University of Maryland Medical Center.
Contaminated Food and Water
Children can become infected with pinworms by ingesting food or drink that's been contaminated by feces containing the worm, the UMMC explains. Pinworms hatch in the small intestine and travel to the large intestine and to the opening of the rectum--the anus--where the female deposits her eggs. Pinworm infections spread rapidly at day care facilities, schools and other large gathering places where good hand-washing techniques aren't always practiced.
Undercooked Pork
Trichinella spiralis roundworm can cause trichinosis, an infection children can get by eating undercooked meat, usually pork, although infections from eating horsemeat, walrus and bear meat have occurred. The larvae, encased in cysts, are released when the child's stomach juices digest the cysts. Larvae pass from the intestine through the bloodstream and can re-encase themselves into cysts in muscle fibers, causing achy joints and muscles.
Fly Bites
The roundworm Onchocerca volvulus infects 20 million people worldwide, most in Africa, the UMMC reports, through day-biting flies, causing an illness called river blindness. River blindness is the leading cause of blindness in the world. Loiasis, another roundworm contracted through day-biting flies, affects between 3 and 13 million people, including children, in Africa.
