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Life Cycle of Hammondia hammondi (Apicomplexa: Sarcocystidae) in Cats

Jitender P Dubey1, David J P Ferguson

  • 1Animal Parasitic Diseases Laboratory, Beltsville Agricultural Research Center, Agricultural Research Service, United States Department of Agriculture, Beltsville, Maryland, 20705-2350, USA.

The Journal of Eukaryotic Microbiology
|October 15, 2014
PubMed

Insights

Hammondia hammondi and Toxoplasma gondii are related feline coccidians. This study details Hammondia hammondi multiplication in cats, revealing similarities and ultrastructural differences in its asexual and sexual development compared to Toxoplasma gondii.

Area of Science:

  • Veterinary Parasitology
  • Cell Biology
  • Feline Infectious Diseases

Background:

  • Hammondia hammondi and Toxoplasma gondii are related feline coccidians.
  • Both parasites undergo asexual and sexual reproduction in feline intestinal enterocytes.
  • T. gondii infects extra-intestinal tissues, while H. hammondi is confined to enterocytes.

Purpose of the Study:

  • To investigate the multiplication and development of H. hammondi within the feline intestine.
  • To compare the life cycle of H. hammondi with that of T. gondii in cats.
  • To provide detailed ultrastructural analysis of H. hammondi development.

Main Methods:

  • Oral inoculation of parasite-free cats with H. hammondi tissue cysts and bradyzoites.
  • Histological examination of feline small intestine at various time points post-inoculation (1, 3, 4, 6, and 7 days).
  • Ultrastructural analysis of parasitic development within enterocytes.

Main Results:

  • Intracellular bradyzoites were observed at 1 and 3 days post-inoculation.
  • Schizonts were identified at 4 days post-inoculation, located above the host cell nucleus.
  • Schizonts and gamonts were present at 6 and 7 days post-inoculation.
  • Ultrastructurally, H. hammondi development resembled T. gondii, but merozoites showed longer rhoptries with more micronemes.

Conclusions:

  • Hammondia hammondi undergoes asexual and sexual development within feline enterocytes.
  • The developmental stages and cellular locations are comparable to Toxoplasma gondii.
  • Distinct ultrastructural features in H. hammondi merozoites differentiate it from T. gondii.

Keywords:
Gamontsschizontsultrastructure

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