Trematodes

flukes

• generally hermaphroditic
• complex life cycles
• all require changes in the intermediate host with some intermediates capable of asexual reproduction
• flat land can contribute to trematode problem

yes

• egg
• egg hatch to Miracidium with cilia and swims
• Miracidium penetrates body of snail
• in the snail Miracidium morphs to Sporocyst
• sporocyst (asexually) divides into 10 Rediae
• 10 Rediae (asexually) divide into 100 Cercariae
• Cercariae leave the snail, swim to grass where they are consumed by ruminant
• metamorphoses occurs and they are capable of sexual reproduction

if weather is in-climate, Cercariae become Metacercariae remaining valiable until warm weather

Cercariae

• Fascioliasis gigantica- giant liver fluke
• Fascioliasis magna- large liver fluke
• Fascioliasis hepatica- common liver fluke
• Dicrocoeliasis lanceatum-lesser liver fluke

bile ducts

• toxin produced by Clostridium novyi
• (moves from dormant state to vegetative state to produce toxin that kills)

as flukes migrate through out liver parenchyma, they disturb and activate dormant spores which will activate to vegetative form releasing toxin that will kill in a matter of hrs/days

• Paragonimus kellicotti
• Nanophytes salmincola

Paragonimus kellicotti

crayfish

toxin from Neorickettsia helminthoeca, which is a rickettsial organism carried by the fluke Nanophyetus salmincola


dog eats salmon=eating Nanophyetus salmincola that carries Neorickettsia helminthoeca causing enteritis in dog

Nanophyetus salmincola

Alaria canis

(non-pathogenic)

Platynosomum concinnum (formerly called Amphimerus felineus)

• inhabits bile ducts
• cats infected following ingestion of lizards or amphibians containing larvae

• Easter
• 4th of July
• Thanksgiving

• identified liver flukes to be one of the top 10 quality issues facing beef industry
• identified in 26 states
• can effect bull fertility

reduced pregnancy rates, weaning weights, rate of gain, and bull fertility