Fascioloides magna “Giant Deer Fluke” Different behavior and pathology in different hosts.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).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!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!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!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).Preziquantel (except for F. hepatica). Rafoxanide: is the drug of choice for F. hepatica!Rafoxanide: is the drug of choice for F. hepatica!

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

Aquatic Vegetation Water Chestnuts

Pickled Fish

Digestive Tract Trematodes

Fasciolopsis buski Order: EchinostomatiformesOrder: Echinostomatiformes Humans, pigsHumans, pigs OrientOrient Large (7.5 cm)Large (7.5 cm) Life cycle similar to FasciolaLife cycle similar to Fasciola

Pathology and Symptoms Severity depends on worm burdenSeverity depends on worm burden IrritationIrritation Excess mucous secretionExcess mucous secretion Ulceration, hemorrhage, AbscessUlceration, hemorrhage, Abscess ObstructionObstruction Chronic diarrheaChronic diarrhea Sensitization to worm metabolitesSensitization to worm metabolites –Leukocytosis –Anemia –Eosinophilia –Nausea/diarrhea –Edema of face and intestinal wall –Death

Treatment PraziquantelPraziquantel

Epidemiology Who gets infected?Who gets infected? Rural to semi-urban areasRural to semi-urban areas School age childrenSchool age children –Prevalence 57% China57% China 25% Taiwan25% Taiwan 50% Bangladesh50% Bangladesh 60% India60% India 10% Thailand10% Thailand

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

Epidemiology Lack of regulation on food industryLack of regulation on food industry Food preparationFood preparation Sanitation (sewage)Sanitation (sewage) Night soilNight soil PigsPigs –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 Vitellaria Testes Mehlis’ gland Ovary uterus Collar of spines around oral sucker

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 (2 nd 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.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.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. AmericaNorthwest N. America Northeast AsiaNortheast Asia Crypts of the small intestineCrypts of the small intestine Human infectionsHuman infections –98% prevalence in Siberian villages PathologyPathology

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

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

Lung Flukes ParagonimusParagonimus bronchiolar lumen and peribronchial tissuesbronchiolar lumen and peribronchial tissues AntigenicAntigenic Become encapsulatedBecome encapsulated –granuloma

Paragonimiasis ParagonimusParagonimus 7 species in Asia, Sub- Saharan Africa, Central and South America7 species in Asia, Sub- Saharan Africa, Central and South America Paragonimus westermaniParagonimus westermani

Life cycle of Paragonimus

Paragonimus cercaria

1 st Int. Host1 st Int. Host –Freshwater snails –Streams –Rice paddies Paragonimus westermani Melanoides tuberculata

Paragonimus westermani 2 nd Int. Hosts:2 nd Int. Hosts: –Potamon Rice PaddiesRice Paddies –Eriocheir StreamsStreams Larvae develop in brackish waterLarvae develop in brackish water

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

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