Medical Microbiology

602 10 Helminths

LarvaMigransExternaor

CutaneousLarvaMigrans(CLM)

(“CreepingEruption”)

Parasites.CLMdesignatesasyndromecausedbymigrationoflarvalpara-

sitesintheskinofaccidentalhosts.Hookwormspeciesofdogsandcats

(e.g.,Ancylostomabraziliense,Ancylostomacaninum)andStrongyloidesspe-

ciesofvarioushosts(mammaliananimals,humans)aremainlyresponsible

forhumanCLM.Otherpotentialcausativeorganismsincludeinsectlarvae

(Hypoderma,Gasterophilus,etc.).

Clinicalmanifestations.Theinfectivelarvaeoftheabove-mentionedhook-

wormspeciescanpenetratehumanskin(feet,hands,otherbodyregions)

uponcontactwithcontaminatedsoil(e.g.,onbathingbeaches)andmigrate

throughthedermis.Thisresultsinpapules,twistedandinflamedworm

burrows,andpruritus(Fig. 1 0. 16 f).Theselarvaerarelypenetratefurther

intothebodyandnormallydonotreachsexualmaturityinthehost

(however,seealsop.580).Thelarvaepersistintheskinforseveralweeks

tomonths,andthentheydie(seep. 617 forcausativeinsectlarvae).

Diagnosisandtherapy.Theclinicalpresentationwithmany 1 – 2 mmwide

andcentimeter-longwormburrowsusuallysufficesforadiagnosis.Recom-

mendedtreatmentsincludetopicalapplicationofthiabendazoleointment

(1 5 %),wettingwithivermectinsolution,spray-freezingwithethylchloride

andperoraltherapywithalbendazoleorivermectin.

LarvaMigransInternaor

VisceralLarvaMigrans(VLM)

Parasites.Themaincausativeagentsofthisdiseasearethelarvaeofvarious

roundwormspeciesfromdomesticandwildanimals,forinstanceToxocara

canisfromdogsandfoxes,T.mystaxfromcats,Baylisascarisprocyonisfrom

raccoonsaswellasroundwormspecies(Anisakidae)frommarinemammals.

Toxocarosisandanisakiosisarediscussedhereasexamplesfromthisgroup.

Angiostrongyliosisanddirofilariosiscanalsobeincludedinthisdisease

category.

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Kayser, Medical Microbiology © 2005 Thieme