Medical Microbiology

586 10 Helminths

everydayuseoraredisseminatedwithdust.Intheintestinaltract,larvae

hatchfromtheingestedeggs,moltrepeatedly,anddevelopintosexuallyma-

turepinwormsinfivetosixweeks.“Retroinfection”isalsoconceivable,

wherebyinfectivelarvaewouldbereleasedattheanustomigrateback

intotheintestine.

Pathogenesisandclinicalmanifestations.Thepinwormslivingonthelarge

intestinemucosaarefairlyharmless.Occasionally,differentstagesofthepin-

wormpenetrateintothewallofthelargeintestineandtheappendixormi-

grateintothevagina,uterus,fallopiantubes,andtheabdominalcavity,where

theycauseinflammatoryreactions.

ThefemalesofEnterobiusproduceinparticularaverystrongpruritusthat

mayresultinnervousdisorders,developmentalretardation,lossofweight

andappetite,andothernonspecificsymptoms.Scratchlesionsandeczema-

touschangesareproducedintheanalareaandcanevenspreadtocoverthe

entireskin.

Diagnosis.Atentativediagnosisbasedonclinicalsymptomscanbecon-

firmedbydetectionofpinwormsspontaneouslyexcretedwithfecesand

eggsadheringtotheperianalskin(Fig. 1 0. 1 ).Standardstoolexamination

techniquesarenotsufficienttofindtheeggs.Eggdetectionbythe“adhesive

tapemethod”hasprovedmostefficient(p.622).

Therapyandprevention.Thefollowingdrugsareeffective:albendazole,me-

bendazole,andpyrantel.Reinfectionsarefrequent,sothattreatmentusually

shouldberepeatedonceormoretimes,extendedtoincludeallpotential

parasite carriers (e.g., family members, kindergarten members), and

combinedwithmeasures,thepurposeofwhichistopreventeggdissemina-

tion:washingtheperianalskin(especiallyinthemorning),coveringitwith

ointments,washingthehands,hotlaunderingofunderwear,andcleaning

contaminatedobjectswithhotwater.

10

Kayser, Medical Microbiology © 2005 Thieme