Parasitology lab notes

3,727 views
3,234 views

Published on

0 Comments
0 Likes
Statistics
Notes
  • Be the first to comment

  • Be the first to like this

No Downloads
Views
Total views
3,727
On SlideShare
0
From Embeds
0
Number of Embeds
7
Actions
Shares
0
Downloads
114
Comments
0
Likes
0
Embeds 0
No embeds

No notes for slide

Parasitology lab notes

  1. 1. Lab 5: Trematodes! Flukes
  2. 2. Trematodes: General Info <ul><li>Phylum: Platyhelminthes – the flatworms </li></ul><ul><li>Unsegmented, leaf-like bodies </li></ul><ul><li>2 subclasses: Monogenea (monogenetic trematodes) & Digenea (digenetic trematodes) </li></ul><ul><li>Monogenetics usually parasitize fish, reptiles & amphibians </li></ul><ul><li>Digenetic trematodes parasitize wild & domestic animals & humans </li></ul>
  3. 3. Trematodes: Morphological Features <ul><li>Mouth connects to pharynx, leads to esophagus, bifurcates into 2 ceca </li></ul><ul><li>No anus: releases cecal contents back through mouth into tissue it infects </li></ul><ul><li>Cecal contents can be seen in histopathologic section and are colloquially referred to as “fluke puke” </li></ul><ul><li>Also possess and acetabulum, or ventral sucker – holdfast organ not associated with feeding </li></ul><ul><li>Near anterior end, mouth </li></ul><ul><li>is surrounded by muscular </li></ul><ul><li>oral sucker </li></ul>
  4. 4. Trematodes: Reproduction <ul><li>With exception of schistosomes (blood flukes) all flukes are hermaphroditic </li></ul><ul><li>Each fluke possesses both sex organs </li></ul><ul><li>Self-fertilization usually takes place, but cross-fertalization can also occur </li></ul>
  5. 5. Flukes: General Life Cycle Part 1 <ul><li>Operculated eggs pass in feces </li></ul><ul><li>Egg comes in contact w/ water – hatches and becomes motile miracidium </li></ul><ul><li>Miracidium seeks out and penetrates skin of aquatic snail (1 st intermediate host) </li></ul><ul><li>In snail, develops into sporocyst – sack in which next stage redia develops </li></ul><ul><li>Each sporocyst contains many redia, each redia many cercaria </li></ul><ul><li>Cercarial stage usually has a tail and will emerge from snail & swim in water. </li></ul>
  6. 6. Flukes: General Life Cycle Part 2 <ul><li>Cercarial stage takes 1 of 3 paths: </li></ul><ul><ul><li>Cercaria may directly penetrate the skin of definitive host </li></ul></ul><ul><ul><li>Cercaria may attach to vegetation, lose its tail, secrete a thick cyst wall around itself and develop into a metacercaria . Vegetation w/ attached metacercaria is ingested by definitive host </li></ul></ul><ul><ul><li>Cercaria may lose its tail, penetrate the 2 nd intermediate host, secrete thick cyst wall & become metacercaria in 2 nd intermediate host. In this case, the 2 nd intermediate host w/ encysted metacercaria is ingested by primary host </li></ul></ul>
  7. 7. Fluke: Life Cycle
  8. 8. Identification of Trematode Ova <ul><li>Singly operculated oval shaped eggs </li></ul><ul><li>Very distinctive </li></ul>
  9. 9. Dicrocoelium dendriticum : Lancet Fluke <ul><li>Definitive hosts: sheep, goats & cattle </li></ul><ul><li>Tiny ~ 6-10mm long </li></ul><ul><li>Live in the fine braches of bile duct – can produce biliary hyperplasia </li></ul><ul><li>Produces brown, embryonated, operculated ova </li></ul><ul><li>Intermediate hosts: snail then ant </li></ul><ul><li>Can be zoonotic if eat chocolate covered ants! </li></ul><ul><li>Found on fecal sedimentation or in bile ducts at necropsy </li></ul>
  10. 10. Fasciola hepatica : Liver Fluke <ul><li>Definitive hosts: ruminants, cattle </li></ul><ul><li>Most pathogenic fluke of cattle in US, very common </li></ul><ul><li>Lives in liver & bile ducts, causes liver rot </li></ul><ul><li>Eggs are large & heavy, should use fecal sedimentation to find </li></ul><ul><li>Intermediate host: snail – develops into metacercaria on vegetation </li></ul><ul><li>Can be zoonotic if eat fress watercress </li></ul><ul><li>Can be found as spurious eggs in dog & cat feces (coprophagy) </li></ul>
  11. 11. Fascioloides magna: Deer Liver Fluke <ul><li>Definitive host: White-tailed deer </li></ul><ul><li>May also use sheep, cattle & pigs as incidental hosts </li></ul><ul><li>Adults found in liver parenchyma </li></ul><ul><li>Adults are Unique in appearance </li></ul><ul><li>Eggs may be found on fecal flotation of deer feces, but not incidental hosts feces </li></ul>
  12. 12. Platynosomum fastosum: Lizard-poisoning Fluke <ul><li>Definitive host: cats </li></ul><ul><li>Intermediate hosts: snail then lizard </li></ul><ul><li>Seen frequently in Southeastern US (FL) </li></ul><ul><li>Adults found in liver, gall bladder, bile ducts </li></ul><ul><li>Signs: v/d, icterus, & anorexia, fever, death </li></ul>
  13. 13. Nanophyetus salmincola: Salmon-poisoning fluke <ul><li>Definitive hosts: dogs, cats, wild carnivores </li></ul><ul><li>Intermediate host: snail then fish (trout & salmon) </li></ul><ul><li>Signs begin 5-7 days after ingestion </li></ul><ul><li>Fluke causes minimal damage, severity is due to rickettsial parasite carried on fluke – causes damage to capillaries, rash, fever, fatal enteritis in dogs </li></ul><ul><li>Zoonotic potential if eat undercooked fish </li></ul>
  14. 14. Paragonimus kellicotti: Lung fluke <ul><li>Definitive hosts: dogs & cats </li></ul><ul><li>Intermediate host: snail, crayfish </li></ul><ul><li>#1 most common small animal fluke </li></ul><ul><li>Can be found in float of feces or sputum </li></ul><ul><li>Adults live in lung parenchyma but are known for getting “off track” – can end up in brain, other organs </li></ul><ul><li>Immature flukes encyst and penetrate intestinal wall, migrate to diaphragm & penetrate into pleural cavity – mature in lungs </li></ul>
  15. 15. Schistosomes of wild birds: Swimmer’s Itch <ul><li>Swimmer’s Itch or schistosome cercarial dermatitis caused by cercarial stage of schistosomes of migrating aquatic birds </li></ul><ul><li>Cercaria penetrate skin of human, causing severe pruritic dermatitis. </li></ul><ul><li>Only true zoonotic degenetic fluke </li></ul>

×