Medical Microbiology

564 10 Helminths

Taeniasolium(PorkTapeworm)

CausativeagentofT.soliumtaeniosisandcysticercosis

Occurrence.T.soliumismainlyendemicinpoorlydevelopedregionsof

CentralandSouthAmerica,Africa,andAsia,withsporadicoccurrence

intheUSAaswellaswestern,eastern,andsouthernEurope.InMexico,

0. 1 – 7 %oftheruralpopulationarecarriersoftheadulttapewormandup
   to 25 %ofthepigscarrythecysticerciofT.solium.Importedhumancases
   ofcysticercosisarebeingdiagnosedinincreasingnumbersinnonendemic
   regions(e.g.,centralEurope,USA).
   Parasiteandlifecycle.T.solium(solium:fromtheArabicwordsosl:chain)
   is 3 – 4 mlongandisthussmallerthanT.saginata.ThescolexofT.soliumhas
   arostellumarmedwithtworowsofhooksinadditiontothefoursuckers
   (Fig. 1 0. 8 ).Insidethegravidsegments,thenumberoflateraluterusbranches
   isusually 7 – 1 3,i.e.,lessthaninT.saginata(usually> 1 5).
   ThelifecycleissimilartothatofT.saginata,exceptthatT.soliumusesthe
   pigasintermediatehost,inwhichthemetacestode(Cysticercuscellulosae)
   developstoinfectivitywithintwotothreemonths.
   Pathogenesisandclinicalmanifestations.T.soliumintheintestinecausesno
   oronlymildsymptoms,similartoinfectionswithT.saginata.
   Diagnosis,therapy,prevention,andcontrol.Therecommendationsmade
   fordiagnosisandtherapyofT.saginataapplyhereaswell.Infectionswith
   T.soliumcanbepreventedbycookingordeep-freezingthepork(–20 8 C
   foratleast 24 hours).Controlmeasuresinendemicareasincludemasstreat-
   mentofthepopulationwithpraziquantel,improvementofhygieneand
   slaughteranimalinspection.

Cysticercosis

Causativeagentandepidemiology.ThemetacestodesofT.solium,knownas

Cysticercuscellulosae,cancolonizevarioushumanorgans(Fig. 1 0. 8 )and

causetheclinicalpictureofcysticercosis.Infectionsoccurunderunhygienic

conditionsduetoperoralingestionofeggsstemmingfromthefecesof

tapewormcarriers(exogenousautoinfectionoralloinfection).Itisassumed

thatoncosphereshatchingfromeggsreleasedfromgravidproglottidsin

thehumandigestivetractmayalsocauseaninfection(endogenousauto-

infection).InsomecountriesofLatinAmerica,Asia,andAfrica,humancysti-

cercosisisapublichealthproblem.InLatinAmericancountries,seropreva-

lencesupto 10 %andabovehavebeenfound,andcysticerciweredetectedin

0. 1 – 6 %oftheautopsycases.
   Clinicalmanifestations.Cysticercosisofthecentralnervoussystem(neuro-
   cysticercosis)oroftheeye(ocularcysticercosis)isamongthemoresevere

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Kayser, Medical Microbiology © 2005 Thieme