Each redia then forms several ____

in the generalized trematode life cycle

1. Form a cyst like metacercaria on aquatic plants

2. Penetrate a second IH and form a cyst like metacercaria in tissue of IH

3. Penetrate a second IH and form an active migrating mesocercaria in tissues of IH or paratenic host

4. Directly penetrate definitve host and mature

What is the size of Alaria?

PPP?

3-10mm

20 days

Eggs in water containing miracidium

Eggs hatch releasing miracidium

Miracidia enter snail

Cercariae develops in tissues of snails

Cercariae penetrate skin of tadpoles and forms mesocercariae

This can be eaten by paratenic host or by dog

Mesocercariae enter the lung of the dog, migrate to instine to become adults and lay eggs

Eggs shed in feces.

Attachment in SI produce mild enteritis

Destruction of lung tissue during migration of mesocercariae

Find large operculated eggs in fecal exam (98-134 x 62-68)

Sedimentation exam

Yes

Humans fatally infected by eating improperly cooked frog's legs

Pulmonary hemorrhage due to migration of mesocercariae

intraocular infection of mesocercariae also reported

Depends on distrubition of snail

SI of dogs, foxes, coyotes, wolves, bears, raccoons and mink

Small (0.5-1.1 mm long)

Eggs operculated, yellowish brown, 45-55 um x 65-80 um

eggs in feces hatch

Miracidium released and penetrates the snail

Metacercaria encysts in snail, multiply, release rediae

these develop into cercariae which penetrate salmonid fish

eaten by dog and develops into adult

Fluke is host to highly pathogenic microorganism (neorickettsia helminthoeca)

ONce in the dog the intracytoplasmic pleomorphic rickettsia is found in reticularendothelial cells of lymphoid tissues of infected animals

Hemorrhagic inflammation of intestine

Flukes and fluke eggs found in large numbers

ileocecal, mesenteric, portal and internal iliac lymphadenopathy

enlarged spleen

INcubation period 5-7 days

Fever 104 then back to normal

conjunctival discharge

anorexia

wt loss

diarrhea, vomiting

lymphadenopathy

death within 7-10 days not uncommon without treatment

History, geographic region

clinical signs

Fluke eggs appear in feces 5-7 days PI

sedimentation exam

aspirate lymph node

Fluids

Antibiotics (doxycycline)

Praziquantel for flukes

Don't let dogs eat fish

freeze fish to kill organisms

Dogs that recover from infection are usually immune for life

Dogs, wild canids, raccoon, nutria, & mink

NC down to FL over to Texas then north to KS

Adults 9-17 mm

Female spends life in gynecophoric groove of the male

occur in mesenteric veins

88 um x 74 um

Contain a miracidium

Eggs laid in mesenteric veins

Eggs penetrate through wall of vessel and enter lumen of intestine (many eggs get trapped w/in wall of mesenteric veins or intestine with formation of granulomas)

eggs shed in feces, if eggs are deposited in water miracidium hatches and tries to penetrate a snail

Once in snail miracidia develop into sporocysts and daughter sporocysts and motile cercariae (infective stage)

penetrate skin of host, develop into schistosomula and migrate to lungs, then liver, to mesenteric veins and mature

Eggs in wall of intestine elicit intense inflammatory reaction with formation of granulomas

Many eggs trapped in intestinal wall

eggs go in venous circulation to various organs where they lodge in small vessels and elicit granulomatous reactions

Coughing

chronic mucoid to hemorrhagic diarrhea

anorexia

anemia

eosinophilia

hypercalcemia

Clinical signs

geographic region

recovery of eggs in fecal sedimentation

observation of eggs in histopath sections

Fenbendazole

praziquantel

Morphology of Platynosomum fastosum

morphology of eggs

4-8 mm long, 1.6mm wide

eggs 41-45 um x 23.3

large operculum

Snails are the first IH (eggs ingested by land snails and develop to redia and then to cecariae)

Second IH are lizards (metacecariae encysted in IH)

Cats become infected by eating lizards

Flukes in bile ducts may cause thickening and cirrhosis

blockage of bile ducts

Find fluke egg in feces (difficult since few are produced)

Sedimentation exam

Praziquantel

Fenbendazole