MIP 260 Exam 3

Dipylidium caninum

• “double-pored dog tapeworm”

• Cestode

• 2 sets of reproductive organs and a genital pore on each side

• armed rostellum

• found in cats (sporadically seen in humans)

• infects flea then animal → gravid proglottids passed in feces

• egg packets → oncosphere → cystercoid (infective)

Diphyllobothrium latum

• cestode

• “broad fish tapeworm”

• Host: fish-eating mammal

• Order: Pseudophyllidea

• Bothria on scolex

• broad proglottids

• eggs embryonate in water → coracidia infect copepod/crustation → develops into procercoid which fish eats → becomes plerocercoid → big fish (paratenic host) eats small, infected fish → human/fish eater eats fish

Taenia solum

• “pork tapeworm”

• Cestode

• Order: Cyclophyllidea

• Scolex has 4 acetabula suckers and rostellum with 2 rows of hooks

• cysticercus in pork muscle →Human eats pork and hexacanth embryo attaches to small intestine wall → eggs or gravid proglottids shed into feces → pigs eat eggs and become infected

• cysticercosis larvae

Moniezia

• DH: hooved animals, IH: mite in orbatidae family

• up to 6 meters, large

• wide proglottids

• unarmed scolex

• two sets of reproductive organs in each proglottid

• eggs released → eggs ingested by mites → animal eats mite → worm matures in small intestine

Mesocestoids

• medioventral genital pores

• widespread in carnivores

• 4 simple suckers and no rostellum

• complete life cycle unknown

• many infect rodent or reptile as IH

• May undergo Asexual reproduction inside a IH by longitudinal fission at the scolex

• Larval form - tetrathyridium (cysticercoid type)

Echinococcus

• Hyatid disease

• common in sheep raising areas

• small, only 3-6 segments

• eggs are taeniid-like (meaning similar to taenia and echinococcus, they are in the same family)

• Larval tapeworm form - hyatid cyst

• DH: canids

• IH: sheep, cattle, pigs, moose, elk, humans, deer, rabbits, goats, horses

Trematodes

• “Flukes”

• Platyhelminth

• Digenea

• At least 1 IH, usually a snail

• Found in most all bodily organs

• Leaf life

Trematode Life Cycle

Egg → Miracidium → Sporocyst → Daughter sporocyst (+/- Rediae) → Cercaria → Metacercaria (INFECTIVE) → Adult

ENTER SNAIL: Miracidium

EXIT SNAIL: Cercaria

ENTER DH: Metacercaria

Fluke Egg

• Heavier than other eggs

• Operculum

Schistosoma sp.

• “Blood flukes”

• Trematode

• Found in domestic animals and birds

• Diecious (2 sexes)

• Cercaria infective (no metacercaria)

• Males have gynecophorical canal in which females lie

• Eggs in bladder and kidneys cause granulomas and fibrosis

Schistosoma mansoni

• eggs released in feces

• lives in intestine

• lateral spine on egg

Signs of Schistosoma

• Cercarial dermatitis

• Fever, malaise

• Abdominal pain

• Liver/spleen/intestinal tenderness, enlargement

• Diarrhea

• Hematuria (blood in urine); dysuria (painful urination)

• Eosinophilia

Schistosoma haematobium

• eggs released in urine

• found in kidney and bladder

• egg has spine at top

Schistosoma japonicum

• eggs released in feces

• found in GI and liver

• eggs have small bump

Fasciola spp.

• “Liver Fluke”

• Trematode

• common in herbivores

• ventral acetabulum close to oral sucker

• Live in liver then bile ducts

• cercaria leave snail and become metacercaria on vegetation (watercress)

Fasciolosis Signs

Can be found with fluke finder

• Fever

• Abdominal pain, malaise

• Weight loss

• Anemia

• Hepatomegaly

Dicrocoelium dendriticum

• “Lancet fluke” due to bladelike shape

• Trematode

• Lives in bile duct of sheep, cattle, goats, pigs, and cervid

• 1st IH: land snail → 2nd IH: ant

• Land snail covers cercaria in slime balls which ants eat

• Metacercaria develop in ant and move to nervous system, causing the ant to climb to the top of vegetation to be eaten

Clonorchis sinesis

• “Chinese Liver Fluke”

• Trematode

• Leaf like with no spines and weak musculature

• eggs released into water

• 1st IH: snail → 2nd IH: freshwater fish → DH: fish-eating mammal

• IN SNAIL: miracidia→ sporocyst → rediae → cercariae

• Adults live in bile ducts

Clonorchis sinesis Signs

Eggs found in stool samples

• Upper abdominal pain, nausea; anorexia

• Diarrhea

• Gallbladder inflammation, granulomas

• Hepatomegaly, jaundice

• Pancreatitis

Heterophyes heterophyes

• Trematode

• Lives in small intestine of fish-eating birds and mammals

• Small, tear shaped flukes

• cercaria swim towards surface of water and penetrate fish musculature

• 1st IH: aquatic snail → 2nd IH: fish → DH: fish-eater → egg passed in feces

Nanophyetus salmincola

• Trematode

• causes rickettsial disease: hyperparasitism

• large oral sucker

• Lives in small intestine of birds and bird eating mammals

• Snail host inhibit fast moving stream

• unembryonated eggs pass down stream and hatch

• rediae inhabit all areas of snail

• metacercariae common in fins, muscle, and kidneys

• 1st IH: snail → 2nd IH: fish (often salmanoid) → DH: fish eater (commonly skunks and racoons)

Paramphistomum cervi

• “rumen fluke”

• Trematode

• amphistome

• large, pigmented cercariae with eye spots

• NO 2nd IH, metacercariae develop on vegetation

• penetrates gut, migrates to lumen, migrates to rumen

• often kills host, no adequate treatment

Cestodes

• “Tapeworms”

• platyhelminths

• segmented worms

• flattened dorsoventrally (top to bottom)

• Scolex with 3 types of suckers:

  

• Scolex may bear a rostellum with hooks

Monenzia benedeni

square egg

Monezia exoansa

triangle egg

Cysticercus

Procercoid

Hydatid Cyst

Cysticercoid