Helminth: Cestodes

Helminth: Cestodes

1. Taenia

   • Overview
     • Human (primary host)
       • T.solium
         • Pig,dogs,cats,sheep
       • T.saginata
         • Cattle
       • Diphyllobothrium
         • Fish
       • Hymenolepis
         • Rodent
       • Echinococcus sp
         • Sheep,cattle,goats
     • Infected
       • Eating raw / undercooked beef
       • drink faeces contaminated water
     • cysticercus activation
       • scolex attach small intestine wall
         • mature weeks later
     • 1 tape worm= 50k eggs/day
       • live up to 25 yrs
   • Lifecycle
     • 1. human poop proglottids + gravid eggs
       • 2. Eggs Mature ----> contaminate farms (animals infected)
         • 3. embryo release in gut, penetrate gutwall into circulation
           • 4. encyst enter muscular tissue
             • 5. 2-3 mo Larvae become infectious (survive months to 35 yrs)
   • Geographical locality
     • T.saginata
       • central asia, M.east, central + eastern africa
     • T.solium
       • S.America, S.East Asia, India, Philippines Africa, E.Europe + China
   • Taeniasis symptoms
     • Asymptomatic
     • GI
       • Worm physical presence
         • abdominal discomfort
         • Epigastric pain
         • Vomitting
     • T.solium - other organs
       • physical mass & inflammation
         • Cyst formation at brain, eye, liver, lung + respective symptoms
   • investigation
     • FBC: marked eosinophilia
     • presence in 3 consecutive stools concentration
     • diff T.solium, T.saginata
       • egg identical
       • examine scolex & gravis proglottid
         • G.p :T.solium 7-13
         • G.p: Tsaginatta
   • Tx
     • praziquantel
       • scolex removal essential
     • Prevention
       • adequate cooking of meat
       • Freezing meat below 10C
       • Personal hygine
       • Proper fecal disposal
   • Cysticercosis
     • Neurocysticercosis symptoms
       • Convulsions
         • cysticerci in brain parenchyma
       • Intercrania hypertension
         • CSF Obstruction
           • headache, nausea,vomitting + vertigo
           • Papilledema
       • Pyschiactric disturbance
     • Dx
       • Stool exam
       • Follow organ
         • CNS
           • CSF immunology
           • neuro-imaging
         • Muscle
           • imaging + biopsy
         • Eye
           • imaging (US)
       • Serology - ELISA
     • Tx
       • Asymptomatic + calcified lesion
         • None
       • Neurological
         • anti-epileptics + anti helminthics
         • albendazole/ praziquantel
         • ++Steroid (reduce imflammatory rxn)
     • Control
       • Survey animals + humans
       • animal tx Oxfendazole
       • test sentinel animal
       • test + tx carrier
       • Latrine + water supply sanitation
         • reduce contamination risk
       • Edu- cook thoroughly

2. Echinococcosus (Hyatid disease )

   • E.granulosus
     • Young age 35y/o
     • Produce cystic lesions
     • locality
       • worldwide
       • rural, sheep raising
       • dog definitive host, human intermediate
     • Hyatid cyst
       • inside
         • daughter cyst
         • Brood capsule
         • Scolices
       • outside
         • host derived fibrous tissue
       • disease
         • compression of organs
           • biliary obstruction
           • bronchial obstruction
           • nal outflow obstruction
           • inc ICP= hydrocephalus
         • rupture
           • massive immune reaction inflammation + anaphylaxis
         • 2nd dary cyst infection
       • dx
         • Serology
           • ELISA 80% sensitive
         • imaging
           • plain film
           • US
           • CT/MRI
             • see daughter cyst
             • diff pyogenic abscess
   • E.multilocularis
     • old age 50y/o
     • invasive solid lesions
     • locality
       • northern hemisphere
       • definitive : fox, dogs, coyote, wolves
       • intermediate: rodents, rare human
     • produce multilocular cyst
     • more resistant to chemo
   • Tx (chemotherapy)
     • Albendazole
       • 400mg bds x4 weeks
         • 2 week rest
           • repeat 3-12 cycle
       • longer for alveolar infxn
     • Mebendazole
     • Praziquantel
     • monitor bone marrow suppression
     • PAIR procedure + albendazole 1-3mo
       • (P)ercutaneous (A)spiration
       • (I)nject hypertonic saline
       • surgical (R)emoval
   • prevention
     • Human
       • Eucation
       • Cook food well
     • Dog
       • dont feed infected vicera
       • prevent dog eating sheep material
       • treat dog w praziquantel 5mg/kg
       • population control
     • Regulation of livestock butchering