ORGANISM 5--Hymenolepis nana
GENERAL CHARACTERISTICS
COMMON NAME: Dwarf tapeworm.
GEOGRAPHICAL DISTRIBUTION: Worldwide.
PATHOGENESIS: Often asymptomatic, variable enteritis, secondary anemia,
eosinophilia.
HABITAT--Small intestines.
INTERMEDIATE HOST: Insects or none (autoinfective).
RESERVOIR HOST: Rodents.
INFECTIVE FORM: Cysticercoid larva.
MODE OF INFECTION: Ingestion.
SPECIMEN OF CHOICE: Feces.
Figure 3-46. Life cycle of Hymenolepis nana.
OVA
SIZE: 35 x 45 mcm (medium).
SHAPE: Round to ovoid.
COLOR: Hyaline.
OPERCULUM: Absent.
CONTENTS: Hexacanth oncosphere.
MISCELLANEOUS: 4 to 8 bipolar filaments.
MD0842
3-54