Trematodes

Question 1

Trematode life cycle

Answer 1

Operculated eggs pass, miracidium hatches if in water, penetrates an aquatic snail, forms sporocysts which produce rediae which produce cercariae that exit snail. They can either form a metacercaria on aquatic plants or enter a 2 IH and form metacercaria in the tissue, or enter a 2 IH and form an active mesocercaria or directly penetrate host and mature

Question 2

Alaria spp.

Answer 2

Forms mesocercaria and penetrates trachea to get to intestine. Clinical signs associated with migration through lungs.

Question 3

Is Alaria spp. zoonotic?

Answer 3

YES by undercooked frog’s legs. Can cause intraocular infection

Question 4

Nanophyetus salmincola

Answer 4

Disease is NOT caused by this, instead caused by Neorickettsia bacteria IN THE parasite. Lives in small intestine and disease apparent only in dogs. PPP is 5-8 days. Penetrates intestine and releases N. helminthoeca, spreads to lymph nodes and somatic viscera which leads to hemorrhagic enteritis. MOST dogs will die within 2 weeks if not treated. Do sedimentation for eggs.

Question 5

What is the treatment for N. salmincola and associated disease?

Answer 5

Prazi, Doxy, supportive care and IV fluids, NOT ZOONOTIC

Question 6

Heterobilharzia americana

Answer 6

Female lives in gynephoric groove of male, occurs in mesenteric veins. Eggs penetrate intestine and if shed in feces, miracidium will hatch in water. They can develop into sporocysts and then into cercariae in IH. Eaten by DH, migrate to lungs and liver.

Question 7

Signs of H. americana

Answer 7

Eggs can block circulation, can form granulomas, coughing, PU/PD, recover non-operculated eggs in sedimentation exam. NOT zoonotic

Question 8

Platynosomum fastosum

Answer 8

Mostly cats, eggs ingested by land snail and then the development occurs and penetrates 2 IH which is lizard. Can cause bile duct thickening, do sedimentation exam, not zoonotic