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 autoinfection. The infective form of parasite for humans is the -
Filariform larvae
Embryonated egg
Adult female
Adult male
Enterobius vermicularus mainly affects children. The gravid female worm lays ova around the anus ,causing itching especially at night .The ova are often carried to the mouth on the fingers & so re-infection or human to human infection takes place. Reference: Harrison20th edition pg 1120
Infection