Transmission is hand to mouth. Re-infection and autoinfection is common and maintain infection since female worms die after depositing eggs on the perianal skin. Eggs remain infective indoors for 2-3 weeks. Incubation period is 1-2 months or longer after ingestion. Eggs hatch in the duodenum, larvae migrate to the cecum, mate and gravitate to the perianal skin where females deposit eggs.
Diagnosis is accomplished by observing biscuit shaped eggs.
Eggs are not destroyed with therapy. Reinfection is common. Families need to be treated as a group. Infection common with crowded living conditions, and day care centers. Eosinophilia is mild or absent.