A 6-year old child who presented with perianal pruritus, excoriation of skin and nocturnal enuresis was found to be infected with a parasite causing auto infection. The causative agent is -
Enterobius vermicularis (threadworm) This helminth is common worldwide and affects mainly children.After the ova are swallowed, development takes place in thesmall intestine but the adult worms are found chiefly in the colon. Clinical features The female lays ova around the anus, causing intense itching, especially at night. The ova are often carried to the mouth on the fingers and so reinfection or human-to-human infection occurs . In females, the genitalia may be involved. The adult worms may be seen moving on the buttocks or in the stool. Investigations Ova are detected in stool samples or by applying the adhesive surface of cellophane tape to the perianal skin in the morning. This is then examined on a glass slide under the microscope. A perianal swab, moistened with saline, also allows diagnosis. Management A single dose of mebendazole (100 mg), albendazole (400 mg), pyrantel pamoate (11 mg/kg) or piperazine (4 g) treats infection and is repeated after 2 weeks to control auto-reinfection. If infection recurs in a family, each member should be treated. All nightclothes and bed linen are laundered during treatment. Fingernails must be kept sho and hands washed carefully before meals. Subsequent therapy is reserved for family members with recurrent infection. Ref Harrison20th edition pg 1077
Trichinella spiralis
Giardialamblia
Enterobius vermicularis
Wuchereria bancrofti
Infection