Allaa Hassan

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 Phylum: Platyhelminthes  Class: Trematoda  Order: Plagiorchiida  Family: Dicrocoeliidae  Genus: Dicrocoelium  Species: Dicrocoelium dendriticum  Liver fluke that is a parasite fluke.  Lives in the liver of its hosts  3 host life cycle  Adult worm chills inside sheep/cow  Lays eggs  Sheds into environment with host’s poo

 Europe  North Asia  North America and Australia  North Africa  Found in areas favoring intermediate hosts ▪ Fields with dry and chalky soils.

 Cows  Sheep ▪ Any ‘grazer’  Although rare, humans, herbivorous, and carnivorous mammals can also serve as definitive hosts  through ingestion of infected ants.  No known vector

 1 st  Land snail  2 nd  Ant

 Sheep  Cows  Land snails  Ants  Goats  Pigs  Llamas  Alpacas

 Captain Higgins  ns ns

 Cows/sheep spread D. dendricitum eggs via poo.  Snails ingest poo along with eggs.  Eggs hatch in snail intestine, parasite crosses the wall of snail gut, settles in digestive gland, matures into fluke.  Fluke produces cercariae, snail’s defense system wraps cercariae in balls of slime.  Slime is coughed up by snail.  Ants ingest slime balls along with cercariae.  Parasite enters ant’s body, wanders, finds its way to a cluster of nerves that control ant’s motor skill.  Most lancet flukes go back to abdomen to form cysts.  1 or 2 stay behind in ants head…

 Once they have control over ant’s motor skills…zombie mode begins.  When the sun goes down, and the temperature is a bit cooler, the infected ant leaves its colony and is driven to the top of a blade of grass.  The ant is driven to clamp its jaws on the blade of grass until the sun rises once again.  (if ant is not eaten) once dawn comes, the ant resumes it daily activities with the colony, as if nothing happened.  This continues night after night until the ant is eaten with blades of grass, by grazers.

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 The flukes shoot out of the ants head and head straight for the liver.  They chill there until they’re adults.  Continue their lifecycle; they stay there, get married, have baby eggs.  Eggs are released into the  bile duct  Intestines  Poo

 Why does the ant come out at night and then head back to the colony after dawn?  Why not stay out during daylight?

 Humans  examine bile/ duodenal fluid for eggs  Animals  stool examination  post-mortem examination of the liver.

 Rare in humans  Most infections are asymptomatic and light  In heavier infections:  Cholecystitis ▪ Inflamed gallbladder  Liver abscesses  Upper abdominal pain.

 Drug of choice  Praziquantel

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