1. Fascioloides magna “Giant Deer Fluke”
Different behavior and pathology in different hosts.

2. Fascioloides magna “Giant Deer Fluke”
Deer and Elk (normal hosts)—Liver migration, then matures in thin-walled fibrous cysts connected with bile ducts. (Well tolerated; eggs shed in feces).

3. Fascioloides magna “Giant Deer Fluke”
Cattle, bison and swine—Liver migration, then encapsulation in thick-walled, closed cysts and no eggs are shed!

4. Fascioloides magna “Giant Deer Fluke”
Sheep and goats: extensive, uninterrupted hepatic migration with out encapsulation; usually fatal; 1 fluke can kill a sheep or goat!

5. Pathology
Pathology in C. sinensis and D. dendriticum: distended bile ducts and erosion of epithelium lining, but no secondary pathology like in F. hepatica!

6. Treatment Preziquantel (except for F. hepatica).
Rafoxanide: is the drug of choice for F. hepatica!

7. Diagnosis Look for eggs in feces! But hard to diagnose (why?).
SPURIOUS INFECTIONS!

8. Aquatic Vegetation
Water Chestnuts

9. Pickled Fish

10. Digestive Tract Trematodes

11. Fasciolopsis buski Order: Echinostomatiformes Humans, pigs Orient
Large (7.5 cm)
Life cycle similar to Fasciola

13. Pathology and Symptoms
Severity depends on worm burden
Irritation
Excess mucous secretion
Ulceration, hemorrhage, Abscess
Obstruction
Chronic diarrhea
Sensitization to worm metabolites
Leukocytosis
Anemia
Eosinophilia
Nausea/diarrhea
Edema of face and intestinal wall
Death

14. Treatment
Praziquantel

15. Epidemiology Who gets infected? Rural to semi-urban areas
School age children
Prevalence
57% China
25% Taiwan
50% Bangladesh
60% India
10% Thailand

16. Epidemiology How do you get fasciolopsiasis? Ingest metacercariae
Commercially raised aquatic plants
Water chestnut
Water caltrop
Water hyacinth
Water lotus
Water lily
Watercress

17. Epidemiology Lack of regulation on food industry Food preparation
Sanitation (sewage)
Night soil
Pigs
Habitat
Food

18. Digestive Tract Trematodes
FAMILY ECHINOSTOMATIDAE - intestinal parasites recognized by their anterior collar of spines.
Echinostoma revolutum - Cosmopolitan parasite of birds and mammals– shows low host specificity
Human cases?

19. Morphology of Adult Echinostoma revolutum
Adults are elongate, up to an inch in length.
Characteristic structure is: their circumoral collar of spines arranged in two rows.
37 spines in E. revolutum.
Internal organs are distinct and easy to identify.

20. Morphology of Adult Echinostoma revolutum
Collar of spines around oral sucker
uterus
Vitellaria Testes Mehlis’ gland Ovary

21. Life Cycle of Echinostoma revolutum
Parasite shows low host specificity throughout cycle
1. Adults occur in birds and mammals.
2. Eggs are released via the feces into an aquatic habitat.
3. Miracidia hatch, swim to snail, and penetrate.

22. Life Cycle of Echinostoma revolutum
4. Sporocysts and rediae occur within snail. Cercariae are released.
5. Cercariae penetrate (2nd intermediate hosts) and encyst as metacercariae.
6. Definitive host is infected by ingesting 2nd intermediate
host, metacercariae excyst in stomach, and adults mature
in small intestine.

23. Order Plagiorchiformes
Family Troglotrematidae: these are oval thick flukes with a spiny tegument and dense vitellaria.
Parasites of lungs, intestine, nasal passages, cranial cavities, and various ectopic locations.

24. Nanophyetus salmincola
Fish Eating
Mammal
(Birds)
Freshwater
Snail
Salmonid fish

25. Nanophyetus salmincola
Northwest N. America
Northeast Asia
Crypts of the small intestine
Human infections
98% prevalence in Siberian villages
Pathology

26. Nanophyetus salmincola
Salmon poisoning
Highly pathogenic
Neorickettsia helminthoeca
Rickettsia
Intracellular bacterium
Typhus
Nanophyetus salmincola is a vector for Neorickettsia helminthoeca.

27. Nanophyetus salmincola
Disease
High Fever
Edema of face
Vomiting
Diarrhea
Death in 10 days to 2 weeks.

28. Lung Flukes Paragonimus bronchiolar lumen and peribronchial tissues
Antigenic
Become encapsulated
granuloma

29. Paragonimiasis Paragonimus
7 species in Asia, Sub-Saharan Africa, Central and South America
Paragonimus westermani

30. Life cycle of Paragonimus

31. Paragonimus cercaria

32. Paragonimus westermani
1st Int. Host
Freshwater snails
Streams
Rice paddies
Melanoides tuberculata

33. Paragonimus westermani
2nd Int. Hosts:
Potamon
Rice Paddies
Eriocheir
Streams
Larvae develop in brackish water

34. Paragonimus kellicotti
Crayfish serve as 2nd IH in North America.
Metacercariae are found in the heart.

35. Paragonimus A number of birds and mammals are know to serve as PH!
Guinea pigs are known to serve as PARATENIC HOSTS for Paraganimus spp. in South America!