Cyclophyllidea Taenia saginataTaenia saginata Taenia soliumTaenia solium Echinococcus granulosusEchinococcus granulosus Echinococcus multilocularisEchinococcus multilocularis Hymenolepis diminutaHymenolepis diminuta Hymenolepis nanaHymenolepis nana Dipylidium caninumDipylidium caninum

Taenia saginata Beef tapewormBeef tapeworm Get infected by eating beefGet infected by eating beef 3-5 meters (20 meters)3-5 meters (20 meters)

Bovid eats egg. Oncosphere hatches, penetrate mucosa and enter blood stream. Go to muscle and develop into a cysticercus Adults in intestine. Gravid proglottids shed in feces. Proglottid degrades and eggs released Human eats cysticerci with muscle. Scolex evaginates and attaches to small intestine

Taenia saginata Pathogenesis Not very pathogenicNot very pathogenic Worm produces antigens = allergic reactionWorm produces antigens = allergic reaction Abdominal discomfortAbdominal discomfort DiarrheaDiarrhea NauseaNausea Abdominal PainAbdominal Pain DizzinessDizziness Loss of apetiteLoss of apetite Obstruction of intestine if intensity is highObstruction of intestine if intensity is high

Taenia saginata Diagnosis and Treatment Look for _____________ in feces.Look for _____________ in feces. ELISAELISA PraziquantelPraziquantel

Epidemiology How do you get infected?How do you get infected? How do bovids get infected?How do bovids get infected?

Taenia solium

Pork tape wormPork tape worm Most dangerous cestode?Most dangerous cestode? –Humans are Definitive hostsDefinitive hosts Intermediate hostsIntermediate hosts CosmopolitanCosmopolitan –Mexico –Central America –South America –India –China –Asia

Taenia solium

Pig eats egg. Oncosphere hatches, penetrate mucosa and enter blood stream. Go to muscle and develop into a ____________ Adults in intestine. Gravid proglottids shed in feces. Proglottid degrades and eggs released Human eats cysticerci with muscle. Scolex evaginates and attaches to small intestine.

Adults in intestine. Gravid proglottids shed in feces. Proglottid degrades and eggs released Human eats egg. Oncosphere hatches, penetrate mucosa and enter blood stream. Go to muscle and develop into a ____________ Dead End

Pathogenesis AdultsAdults –Not serious CysticerciCysticerci –Cysticercosis –Establish in many tissues Connective tissuesConnective tissues BrainBrain EyeEye MusclesMuscles HeartHeart LiverLiver LungsLungs

Human muscular cysticercosis

Human Neurocysticercosis and Ophtalmocysticercosis

Cysticercosis Seriousness depends onSeriousness depends on –Location –Number –Immune response FibrosisFibrosis Damage to eyeDamage to eye BrainBrain –Epilepsy –Nervous system malfunction –Blindness –Paralysis –Disorientation Mechanical PressureMechanical Pressure Cysticerci begin to degenerateCysticerci begin to degenerate Inflammatory responseInflammatory response –Brain –eye

Diagnosis Look for _____________ in feces.Look for _____________ in feces. ELISAELISA MRIMRI X-raysX-rays

Eggs with well developed hexacanth and striated embryophore; x µm.Eggs with well developed hexacanth and striated embryophore; x µm. Eggs

Treatment and Prognosis NiclosamideNiclosamide –Only acts on adults PraziquantelPraziquantel –Can kill cysticerci –Death elicits immune response –Brain: Seizures –Is this worse than natural progression? –Steroids SurgerySurgery

Epidemiology How does a human get infected with adults?How does a human get infected with adults? How does a human get infected with cysticerci?How does a human get infected with cysticerci? AutoinfectionAutoinfection

Santo Domingo, a rural community in the state of Yucatan.

Pigs acquire cysticercosis because….

Swine cysticercosis

Differential Diagnosis Taenia solium and Taenia saginataTaenia solium and Taenia saginata Importance?Importance?

Statistics EpilepsyEpilepsy –1.7% Ecuador –2.1% Columbia –3.7% Nigeria 6 times higher than developed nations6 times higher than developed nations MexicoMexico –12% neurological hospital beds

Economic Cost $15 million Mexico for hospital admission$15 million Mexico for hospital admission Pork industry MexicoPork industry Mexico –$43 million in meat loss

Taenia solium Emerging Infectious Diseases March 2004Emerging Infectious Diseases March 2004 OregonCalifornia Years # Cases 43? # Deaths 6124 Born in Mexico 72%72.6% % from US 18%14% Age at death