infectious diseases
Pinworm Infestation
Pathophysiology of Pinworm Infestation
Pinworm ova become infective within a few hours of reaching the perineum. Infestation usually results from transfer of ova from the perianal area to fomites (clothing, bedding, furniture, rugs, toys, toilet seats), from which the ova are picked up by the new host, transmitted to the mouth, and swallowed. Thumb sucking is a risk factor. Reinfestation (autoinfestation) easily occurs through finger transfer of ova from the perianal area to the mouth. Pinworm infections have also been attributed to anilingus among adults. Pinworms reach maturity in the lower gastrointestinal tract within 2 to 6 weeks. The female worm migrates out of the anus to the perianal region (usually at night) to deposit ova. The sticky, gelatinous substance in which the ova are deposited and the movements of the female worm cause perianal pruritus. The ova can survive on fomites as long as 3 weeks at normal room temperature. 