Pathogenic Classification & Life
Cycles of Common Parasites
Eggs passed out of body through feces.
Eggs hatch on the ground & are eaten by an animal.
Enter intestine
The larvae penetrate the intestinal wall .
Model Agricultural Core Curriculum: Supplement
University of California, Davis
275.T 1

Pathogenic Classification & Life
Cycles of Common Parasites
Model Agricultural Core Curriculum: Supplement
University of California, Davis
Larvae grow & develop in lungs.
275.T 2
Enter bloodstream
Larvae move through blood to the liver.
Enter lungs

Pathogenic Classification & Life
Cycles of Common Parasites
Larvae mature & reproduce.
Larvae are coughed up, re-swallowed, & return to intestines.
Model Agricultural Core Curriculum: Supplement
University of California, Davis
275.T 3

Pathogenic Classification & Life
Cycles of Common Parasites
Animal ingests intermediate host & receive larvae.
Larvae turn into adult.
Adult lives in small intestine & feeds off of host.
Model Agricultural Core Curriculum: Supplement
University of California, Davis
275.T 4

Pathogenic Classification & Life
Cycles of Common Parasites
Model Agricultural Core Curriculum: Supplement
University of California, Davis
Adult body is made up of egg-filled worm segments.
Egg-filled segments leave body through the feces.
275.T 5

Pathogenic Classification & Life
Cycles of Common Parasites
Larvae develop in intermediate hosts.
Beetles, Mosquitoes,
Crickets, etc. ingest eggs (intermediate host).
Model Agricultural Core Curriculum: Supplement
University of California, Davis
275.T 6

Pathogenic Classification & Life
Cycles of Common Parasites
Adult lays egg directly in the water or on dry surfaces.
Eggs hatch to larval form once they are moistened.
Larvae change to pupa form in water.
Model Agricultural Core Curriculum: Supplement
University of California, Davis
275.T 7

Pathogenic Classification & Life
Cycles of Common Parasites
Carries many diseases:
Encephalitis, malaria, fowl pox, etc.
Model Agricultural Core Curriculum: Supplement
University of California, Davis
Metamorphosis occurs changing larvae to adult.
275.T 8

Pathogenic Classification & Life
Cycles of Common Parasites
Adult fly lay eggs onto horse’s leg.
(up to 500)
Horse licks leg.
Eggs get into mouth.
Model Agricultural Core Curriculum: Supplement
University of California, Davis
275.T 9

Pathogenic Classification & Life
Cycles of Common Parasites
Model Agricultural Core Curriculum: Supplement
University of California, Davis
275.T 10
Eggs hatch in mouth.
Larvae develop in mouth and is swallowed.

Pathogenic Classification & Life
Cycles of Common Parasites
Pupa burrow into the ground until adult fly emerges during warm weather. (4 to 8 weeks)
Larvae change into pupal stage & leave with feces.
Model Agricultural Core Curriculum: Supplement
University of California, Davis
275.T 11
Larvae migrate to stomach and attach to stomach walls for
8 to 10 months.

Pathogenic Classification & Life
Cycles of Common Parasites
Scolex
Proglottids
Model Agricultural Core Curriculum: Supplement
University of California, Davis
275.T 12