As the name suggests, Capillaria philippinensis is endemic in the Philippines and epidemics have occurred in the Northern Luzon region. The parasite is also ...SkipdirectlytositecontentSkipdirectlytopageoptionsSkipdirectlytoA-ZlinkParasites-Capillariasis(alsoknownasCapillariaInfection)SectionNavigationCDCHomeFacebookTwitterLinkedInSyndicateBiology-LifeCycleofCapillariaphilippinensisMinusRelatedPagesCausalAgentThenematode(roundworm)Capillaria(=Paracapillaria)philippinensiscauseshumanintestinalcapillariasis.UnlikeC.hepatica,humansaremostlikelythemaindefinitivehost.Transmissionoccursprimarilythrougheatingundercookedfish.LifeCycleViewLargerTypically,unembryonated,thick-shelledeggsarepassedinthehumanstoolandbecomeembryonatedintheexternalenvironmentin5—10days;afteringestionbyfreshwaterfish,larvaehatch,penetratetheintestine,andmigratetothetissues.Ingestionofraworundercookedfishresultsininfectionofthehumanhost.TheadultsofCapillariaphilippinensisareverysmall(males:2.3to3.2mm;females:2.5to4.3mm)andresideinthehumansmallintestine,wheretheyburrowinthemucosa.Inadditiontotheunembryonated,shelledeggswhichpassintotheenvironment,thefemalescanalsoproduceeggslackingshells(possessingonlyavitellinemembrane),whichbecomeembryonatedwithinthefemale’suterusorintheintestine.Thereleasedlarvaecanre-invadetheintestinalmucosaandcauseinternalautoinfection.Thisprocessmayleadtohyperinfection(amassivenumberofadultworms).HostsWhilepiscivorousbirdshavebeensuggestedasawildlifereservoirofC.philippinensis,thishasnotbeenwellsubstantiatedbasedonfieldobservations.Experimentaltrialshaveestablishedheavypatentinfectionsinseveralbirdspecies(particularlyherons,egrets,andbitterns),butextensivesurveysofwildbirdsinendemicareashavelargelyfailedtodetectinfection.Manyspeciesoffreshwaterfishappearsusceptibletoinfectionandactasintermediatehosts.GeographicDistributionAsthenamesuggests,CapillariaphilippinensisisendemicinthePhilippinesandepidemicshaveoccurredintheNorthernLuzonregion.TheparasiteisalsoendemicinThailand,andspor