Trichinella spiralis, parasitic worm of the phylum Nematoda that causes trichinosis, a serious disease in humans and other mammals, including pigs, cats, ...TrichinellaspiralisSections&MediaArticleIntroduction&QuickFactsMediaImagesAdditionalInfoMoreArticlesOnThisTopicContributorsArticleHistoryHomeScienceBugs,Mollusks&OtherInvertebratesTrichinellaspiralisnematodePrintCiteverifiedCiteWhileeveryefforthasbeenmadetofollowcitationstylerules,theremaybesomediscrepancies.Pleaserefertotheappropriatestylemanualorothersourcesifyouhaveanyquestions.SelectCitationStyleMLAAPAChicagoManualofStyleCopyCitationShareShareSharetosocialmediaFacebookTwitterURLhttps://www.britannica.com/animal/trichinaMoreGiveFeedbackExternalWebsitesFeedbackCorrections?Updates?Omissions?Letusknowifyouhavesuggestionstoimprovethisarticle(requireslogin).FeedbackTypeSelectatype(Required)FactualCorrectionSpelling/GrammarCorrectionLinkCorrectionAdditionalInformationOtherYourFeedbackSubmitFeedbackThankyouforyourfeedbackOureditorswillreviewwhatyou’vesubmittedanddeterminewhethertorevisethearticle.JoinBritannica'sPublishingPartnerProgramandourcommunityofexpertstogainaglobalaudienceforyourwork!ExternalWebsitesMolecularExpressions-TrichinaWormMedicineNet.com-TrichinaSpiralisByTheEditorsofEncyclopaediaBritannicaViewEditHistoryTrichinellaSpiralisSeeallmediaRelatedTopics:FoodborneillnessTrichinosisEndoparasitism...(Showmore)FullArticleTrichinellaspiralis,parasiticwormofthephylumNematodathatcausestrichinosis,aseriousdiseaseinhumansandothermammals,includingpigs,cats,dogs,bears,foxes,andrats.Thewormoccursworldwide.Itrangesinlengthfrom1.5to4mm(0.06to0.2inch),malesbeingsmallerthanfemales.Matingtakesplaceinthehost’ssmallintestine,afterwhichthefertilizedfemalesburrowintotheintestinalwallandreleasetheirlarvae.Thelarvae,inturn,aretransportedbythebloodstreamtoallpartsofthebody.Thewormgrowswithinmuscletissue,requiringapproximately16daystomature.Acystdevelopsaroundthelarva’sbody.Furtherdevelopmentoccursifthemuscletissuecontainingthee