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

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).

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

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!

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

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

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

Aquatic Vegetation Water Chestnuts

Pickled Fish

Digestive Tract Trematodes

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

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

Treatment Praziquantel

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

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

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

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?

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.

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

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.

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.

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.

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

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

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

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

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

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

Life cycle of Paragonimus

Paragonimus cercaria

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

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

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

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!