Fascioloides magnaFascioloides magna “Giant Deer Fluke” “Giant Deer Fluke”

• Different behavior and Different behavior and pathology in different pathology in different hosts.hosts.

Fascioloides magnaFascioloides magna “Giant Deer Fluke” “Giant Deer Fluke”

• Deer and Elk (normal Deer and Elk (normal hosts)—Liver hosts)—Liver migration, then migration, then matures in thin-walled matures in thin-walled fibrous cysts fibrous cysts connected with bile connected with bile ducts. (Well tolerated; ducts. (Well tolerated; eggs shed in feces). eggs shed in feces).

Fascioloides magnaFascioloides magna “Giant Deer Fluke” “Giant Deer Fluke”

• Cattle, bison and Cattle, bison and swine—Liver swine—Liver migration, then migration, then encapsulation in thick-encapsulation in thick-walled, closed cysts walled, closed cysts and no eggs are shed!and no eggs are shed!

Fascioloides magnaFascioloides magna “Giant Deer Fluke” “Giant Deer Fluke”

• Sheep and goats: Sheep and goats: extensive, extensive, uninterrupted hepatic uninterrupted hepatic migration with out migration with out encapsulation; usually encapsulation; usually fatal; 1 fluke can kill a fatal; 1 fluke can kill a sheep or goat!sheep or goat!

PathologyPathology

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

TreatmentTreatment

• Preziquantel (except for Preziquantel (except for F. hepaticaF. hepatica).).

• Rafoxanide: is the drug of choice for Rafoxanide: is the drug of choice for F. F. hepaticahepatica!!

DiagnosisDiagnosis

• 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 VegetationAquatic Vegetation

Water Chestnuts

Pickled FishPickled Fish

Digestive Tract TrematodesDigestive Tract Trematodes

Fasciolopsis buskiFasciolopsis buski

• Order: Order: EchinostomatiformesEchinostomatiformes

• Humans, pigsHumans, pigs

• OrientOrient

• Large (7.5 cm)Large (7.5 cm)

• Life cycle similar to Life cycle similar to FasciolaFasciola

Pathology and SymptomsPathology and Symptoms• Severity depends on worm burdenSeverity depends on worm burden• Irritation Irritation • Excess mucous secretionExcess mucous secretion• Ulceration, hemorrhage, Abscess Ulceration, hemorrhage, Abscess • Obstruction Obstruction • Chronic diarrheaChronic diarrhea• Sensitization to worm metabolitesSensitization to worm metabolites

– LeukocytosisLeukocytosis– AnemiaAnemia– EosinophiliaEosinophilia– Nausea/diarrheaNausea/diarrhea– Edema of face and intestinal wallEdema of face and intestinal wall– DeathDeath

TreatmentTreatment

• PraziquantelPraziquantel

EpidemiologyEpidemiology

• Who gets infected?Who gets infected?• Rural to semi-urban areasRural to semi-urban areas• School age childrenSchool age children

– PrevalencePrevalence• 57% China57% China

• 25% Taiwan25% Taiwan

• 50% Bangladesh50% Bangladesh

• 60% India60% India

• 10% Thailand10% Thailand

EpidemiologyEpidemiology

• How do you get fasciolopsiasis?How do you get fasciolopsiasis?• Ingest metacercariaeIngest metacercariae• Commercially raised aquatic plants Commercially raised aquatic plants

Water chestnutWater chestnut– Water caltropWater caltrop

– Water hyacinthWater hyacinth

– Water lotusWater lotus

– Water lilyWater lily

– WatercressWatercress

EpidemiologyEpidemiology

• Lack of regulation on food industryLack of regulation on food industry

• Food preparationFood preparation

• Sanitation (sewage)Sanitation (sewage)

• Night soilNight soil

• PigsPigs– HabitatHabitat– FoodFood

Digestive Tract TrematodesDigestive 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 Morphology of Adult Echinostoma Echinostoma revolutumrevolutum

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 Morphology of Adult Echinostoma Echinostoma revolutumrevolutum

Vitellaria Testes Mehlis’ gland Ovary

uterus

Collar of spines around oral sucker

Life Cycle ofLife Cycle of Echinostoma Echinostoma revolutumrevolutum

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 ofLife Cycle of Echinostoma Echinostoma revolutumrevolutum

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 maturein small intestine. 

Order PlagiorchiformesOrder Plagiorchiformes

• Family Troglotrematidae: these are oval Family Troglotrematidae: these are oval thick flukes with a spiny tegument and thick flukes with a spiny tegument and dense vitellaria.dense vitellaria.

• Parasites of lungs, intestine, nasal passages, Parasites of lungs, intestine, nasal passages, cranial cavities, and various ectopic cranial cavities, and various ectopic locations.locations.

Nanophyetus salmincolaNanophyetus salmincola

Fish Eating Mammal(Birds)

Freshwater Snail

Salmonid fish

Nanophyetus salmincolaNanophyetus 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 98% prevalence in Siberian

villagesvillages

• Pathology Pathology

Nanophyetus salmincolaNanophyetus salmincola

• Salmon poisoningSalmon poisoning• Highly pathogenicHighly pathogenic• Neorickettsia helminthoecaNeorickettsia helminthoeca

– RickettsiaRickettsia– Intracellular bacteriumIntracellular bacterium– TyphusTyphus

• Nanophyetus salmincolaNanophyetus salmincola is a is a vector for vector for Neorickettsia Neorickettsia helminthoecahelminthoeca..

Nanophyetus salmincolaNanophyetus salmincola

• DiseaseDisease– High FeverHigh Fever– Edema of faceEdema of face– VomitingVomiting– DiarrheaDiarrhea– Death in 10 days to 2 weeks.Death in 10 days to 2 weeks.

Lung FlukesLung Flukes• ParagonimusParagonimus• bronchiolar lumen bronchiolar lumen

and peribronchial and peribronchial tissues tissues

• AntigenicAntigenic• Become Become

encapsulatedencapsulated– granulomagranuloma

ParagonimiasisParagonimiasis

• ParagonimusParagonimus

• 7 species in Asia, Sub-7 species in Asia, Sub-Saharan Africa, Central Saharan Africa, Central and South Americaand South America

• Paragonimus westermaniParagonimus westermani

Life cycle of Life cycle of ParagonimusParagonimus

ParagonimusParagonimus cercaria cercaria

• 11stst Int. Host Int. Host– Freshwater snailsFreshwater snails– StreamsStreams– Rice paddiesRice paddies

Paragonimus westermaniParagonimus westermani

Melanoides tuberculata

Paragonimus westermaniParagonimus westermani

• 22ndnd Int. Hosts: Int. Hosts:– PotamonPotamon

• Rice PaddiesRice Paddies

– EriocheirEriocheir• StreamsStreams

• Larvae develop Larvae develop in brackish in brackish waterwater

Paragonimus kellicottiParagonimus kellicotti• Crayfish serve as Crayfish serve as

22ndnd IH in North IH in North America. America.

• Metacercariae Metacercariae are found in the are found in the heart.heart.

ParagonimusParagonimus

• A number of birds and A number of birds and mammals are know to mammals are know to serve as PH!serve as PH!

• Guinea pigs are known Guinea pigs are known to serve as to serve as PARATENIC HOSTS PARATENIC HOSTS for for ParaganimusParaganimus spp. spp. in South America!in South America!