Cyclophyllidea Taenia saginata Taenia solium Echinococcus granulosus Echinococcus multilocularis Hymenolepis diminuta Hymenolepis nana Dipylidium caninum

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

Adults in intestine. Gravid proglottids shed in feces 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 Bovid eats egg. Oncosphere hatches, penetrate mucosa and enter blood stream. Go to muscle and develop into a cysticercus

Taenia saginata Pathogenesis Not very pathogenic Worm produces antigens = allergic reaction Abdominal discomfort Diarrhea Nausea Abdominal Pain Dizziness Loss of apetite Obstruction of intestine if intensity is high

Taenia saginata Diagnosis and Treatment Look for _____________ in feces. ELISA Praziquantel

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

Taenia solium

Taenia solium Pork tape worm Most dangerous cestode? Cosmopolitan Humans are Definitive hosts Intermediate hosts Cosmopolitan Mexico Central America South America India China Asia

Taenia solium

Adults in intestine. Gravid proglottids shed in feces 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. 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 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 Adults Cysticerci Not serious Cysticercosis Establish in many tissues Connective tissues Brain Eye Muscles Heart Liver Lungs

Human muscular cysticercosis

Human Neurocysticercosis and Ophtalmocysticercosis

Cysticercosis Seriousness depends on Fibrosis Damage to eye Brain Location Number Immune response Fibrosis Damage to eye Brain Epilepsy Nervous system malfunction Blindness Paralysis Disorientation Mechanical Pressure Cysticerci begin to degenerate Inflammatory response eye

Diagnosis Look for _____________ in feces. ELISA MRI X-rays

Eggs Eggs with well developed hexacanth and striated embryophore; 35-40 x 30-32 µm.

Treatment and Prognosis Niclosamide Only acts on adults Praziquantel Can kill cysticerci Death elicits immune response Brain: Seizures Is this worse than natural progression? Steroids Surgery

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

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

Pigs acquire cysticercosis because….

Pigs acquire cysticercosis because….

Pigs acquire cysticercosis because….

Swine cysticercosis

Differential Diagnosis Taenia solium and Taenia saginata Importance? 7-13 15-20

Statistics Epilepsy 6 times higher than developed nations Mexico 1.7% Ecuador 2.1% Columbia 3.7% Nigeria 6 times higher than developed nations Mexico 12% neurological hospital beds

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

Taenia solium Emerging Infectious Diseases March 2004 Oregon California Years 1995-2000 1989-2000 # Cases 43 ? # Deaths 6 124 Born in Mexico 72% 72.6% % from US 18% 14% Age at death 33 39.9