VMP 920 Infection & Immunity II Veterinary Parasitology Trematoda

Fasciola hepatica Large, leaf-like, liver/bile duct flukes Small anterior suckers Dendritic Intestines, Testes & Ovary

Life Cycle -- Aquatic Definitive Hosts Ova Miracidia Cattle, Sheep, Goats Camelids Ova Miracidia Snail 1st Intermediate Host Pond / Puddle snails (aquatic) Sporocysts and Redia Cercaria 2nd Intermediate Host (or Environment) Metacercaria Aquatic or Semi-aquatic Vegetation Young Flukes Young flukes migrate from intestine via peritoneal cavity to the liver Young flukes migrate through liver parenchyma before maturing in bile ducts Prepatent period: about 2 months Entire Life Cycle: 3-6 months

Geographic Distribution Gulf Coast States, especially Florida Pacific Northwest Not endemic in North Carolina (WHY?)

Pathology Acute Chronic Due to migration of young flukes through liver Severe liver damage, hemorrhage, inflammation Usually results in sudden death, especially in sheep Chronic Due to adults in bile ducts Loss of condition, weakness, hemolytic anemia (proline-induced), hypoproteinemia Liver fibrosis, cholangiohepatitis Calcification & Stenosis of Bile Ducts Usually results in liver condemnation

Diagnosis Fecal Sedimentation Clinical Signs: Liver Enzyme Analysis Acute: abdominal pain, unwilling to move, sudden death Chronic: Loss of condition, weakness, signs of anemia, edema & ”bottle-jaw“. Liver Enzyme Analysis Necropsy Herd History

Treatment Clorsulon (Curatrem) Albendazole Not licensed for breeding dairy cattle 8 day pre-slaughter withdrawal time Albendazole 27 day pre-slaughter withdrawal time

Control = break the life cycle

Control Snail Control Grazing Control Strategic Drug Control molluscicides adequate drainage of pastures Grazing Control Restrict access to wet areas Strategic Drug Control Ivermectin + Clorsulon (Ivomec Plus) Early fall in Southern US

Zoonosis Human Fascioliasis Halzoun Europe, Africa, Cuba, South America Potentially (US Gulf Coast, Florida, Pacific NW) Halzoun Ingestion of raw liver Adults attach to naso-pharynx Middle East

Dicrocoelium dendriticum Lancet Fluke Translucent, lancet-shaped bile duct flukes. Ventral sucker in anterior half of body. Glodular Tandem Testes Posterior to the Ventral sucker, Globular Ovary posterior to testes.

Life Cycle -- Terrestrial Definitive Hosts Ruminants (Sheep, Goats, Cows) Other Hosts (pigs, deer, woodchucks, rabbits, humans => zoonotic) Ova passed in feces. Miracidium remains in egg Snail 1st Intermediate Host (ingests fluke egg) Terrestrial Snail Sporocysts Cercaria in snail slime balls 2nd Intermediate Host (Ingests slime ball w/ larval fluke) Metacercaria Ants Young Flukes Young flukes migrate from intestine via peritoneal cavity to the liver Young flukes migrate to the bile ducts & mature. Prepatent period: 50 days Adults can live 6 years or longer

Dicrocoelium dendriticum

Pathology & Diagnosis Pathology (mainly in small ruminants) Diagnosis Non-pathogenic in younger animals Bile duct hyperplasia, hepatic cirrhosis Slow chronic progressive disease causing decreased productivity in older animals (ewes) Diagnosis Edema, emaciation in older stock Ova in sedimentation Geography: Widely Distributed around the World Northeast US & Canada (Why not NC?)

Treatment & Control Treatment Control Albendazole in high doses Eradicate Ant hills & Snails May not be feasible