4. Paragonimidae, Dicrocoelidae, Opistorchiidae

lemon-shaped flukes resembling small coffee beans occurring in lungs of carnivores and man

Family Paragonimidae

densely-covered w/ scale-like spines

teguments

cirrus and cirrus sac

absent

lung flukes

Family Paragonimidae

1st IH

FW snails (Brotia asperata)

2nd IH

Crustaceans (Sundathelphusa philippina)

only genus of Family Paragonimidae

Paragonimus

In Asia and Oceania:

P. westermani (most widely distributed), P. skjrabini, P. miyazaki, P. heterotremus

In Western, Sub-Saharan Africa:

P. africanus, P. uterobilateralis

In South and Central America:

P. mexicanus

In North America:

P. kellicotti

usually live in pairs in cysts in lungs; either triploid or diploid

P. westermani

snail IH of P. westermani

Family Thieridae

P. westermani stages

sporocysts, rediae, cercariae (microcercous)

what facilitates excystation in the duodenum of the DH?

cysteine protease produced by juveniles

route of excystation of Paragonimus:

duodenum > abdominal wall > coelom > diaphragm and pleura > mate or wait > lungs (where they form a cyst together)

source of infective eggs:

completely raw crab or shellfish, contamination during food prep

occurence of flukes in the brain causes:

cerebral cysticercosis

occurence of flukes in the spinal cord causes:

partial or total paralysis

center of pseudotubercles:

eggs

diagnosis:

examination of sputum, aspirated pleural fluid, feces, surgical findings

differential diagnosis may be:

TB, pneumonia, spirochaetosis

treatment and control:

praziquantel, fenbendazole, albendazole, good hygiene

occurs in a variety of mammals in North America with a month-long prepatent period, IH of this species - Pomatiopsis lapidaria

Paragonimus kellicotti

flattened lanceolate flukes w/ transparent teguments

Family Dicrocoeliidae

1st IH of D. dendriticum

land snails (ex. Zebrina detrita)

2nd IH D. dendriticum

arthropods (ex. ants)

lancet fluke, occuring in bile ducts of sheep, cattle, goats, pigs, cervids, and man, DOES NOT occur in Australia

Dicrocoelium dendriticum

egg description of D. dendriticum:

very small, oval, dark brown, and operculate

infective stage of D. dendriticum

metacercariae

typical effects of D. dendriticum infection

general biliary dysfunction, bile duct inflamation and fibrosis, hepatocyte degeneration

treatment for D. dendriticum infection

flukecides, praziquantel for humans

pancreas flukes

Eurytrema spp.

1st IH of Eurytrema spp.

land snails (ex. Cathaica ravida sieboldtiana)

2nd IH of Eurytrema spp.

orthopteran insects (ex. grasshoppers)

Eurytrema species in pancreatic and bile ducts, occassionally duodenum of ruminants, camel, and man

E. pancreaticum

No redial stage

E. pancreaticum

Associated w/ adenocarcinoma in humans

E. pancreaticum

Treatment for E. pancreaticum

praziquantel

lanceolate fluke in bile and pancreatic ducts of CATS

Platynosomum fastosum

1st IH of P. fastosum

Sublima octona

2nd IH of P. fastosum

isopod crustaceans, lizard (Anolis cristatellus), toad

Prepatent period of P. fastosum DH

8-12 weeks

Treatment for P. fastosum

praziquantel, surgical removal of flukes

"carcinogenic flukes" infecting approx. 30 million humans, with "shoulders" and abopercular knob

Family Opisthorchiidae

Chinese or oriental liver flukes in bile ducts of man, dog, cat, pig, rat, and camel

Opisthorchis sinensis

O. sinensis egg production

up to 4000 eggs/ day for 6 months

1st IH of O. sinensis

Parafossalurus manchouricus, Bulinus, Bythinia, Melania, Vivipara

2nd IH of O. sinensis

cyprinoid fishes (cercaria attach to the skin and encyst under scales or in muscles)

O. sinensis stages in snail:

miracidium, sporocyst, redia, cercaria (5-50 per redia)

route of excystation in O. sinensis:

duodenum > common bile duct > liver

prepatent period of O. sinensis

~ 1 month

life cycle of O. sinensis

completed in 3 months, longevity in humans lasts for at least 8 years

disease caused by family opisthorchiidae

Opisthorchiosis, jaundice, hepatic insufficiency due to obstruction

associated with advanced opisthorchiosis:

cholangiocarcinoma (cancer of bile ducts)

Treatment for Opistorchis infection

praziquantel