ORGANISM 8: Dirofilaria immitis
GENERAL CHARACTERISTICS
COMMON NAME: Dog heartworm.
GEOGRAPHICAL DISTRIBUTION: Worldwide, prevalent in tropics and subtropics.
PATHOGENESIS: In dogs: chronic endocarditis; in humans: granulomas and
pneumonitis.
HABITAT: Heart and lungs.
VECTOR: Mosquitoes.
RESERVOIR HOST: Dogs, which are the definitive hosts.
INFECTIVE FORM: Filariform larva.
MODE OF INFECTION: Inoculation.
PERIODICITY: None.
SPECIMEN OF CHOICE: Blood.
SPECIMEN PROCESSING: Giemsa's or Hematoxylin/Eosin stains.
MICROFILARIA
SIZE: 285 to 315 mcm.
SHEATH: Absent.
TAIL: Slender and pointed.
TERMINAL NUCLEI: Do not extend to the tip of the tail.
MD0842
4-47