ORGANISM 4 Trichostrongylus species
GENERAL CHARACTERISTICS
COMMON NAME: None.
GEOGRAPHICAL DISTRIBUTION: Worldwide.
PATHOGENESIS: Inflammation of the intestinal mucosa and gallbladder in heavy
infections; secondary anemia, transient eosinophilia;
usually asymptomatic.
HABITAT: Small intestines.
INTERMEDIATE HOST: None.
RESERVOIR HOST: Dependant on the species.
INFECTIVE FORM: Semi-filariform larva.
MODE OF INFECTION: Ingestion.
SPECIMEN OF CHOICE: Feces.
Figure 4-9. Life cycle of Trichostrongylus species.
OVA
SIZE: 40 x 90 mcm.
SHAPE: Ellipsoidal, slightly pointed ends.
COLOR: Hyaline.
OPERCULUM: Absent.
CONTENT: Yolk mass.
SHELL WALL: Thin, double.
MD0842
4-13