Sequential histopathology of cavitary liver abscess. Formation induced by axenically grown Entamoeba histolytica

Area of Science:

• Medical Parasitology
• Infectious Diseases
• Pathogenesis Research

Background:

• Entamoeba histolytica is a protozoan parasite responsible for amebiasis.
• Experimental models are crucial for understanding amebiasis pathogenesis and developing treatments.
• The development of amebic abscesses, particularly in the liver, is a severe manifestation of infection.

Purpose of the Study:

• To investigate the effect of serial liver passage on the virulence of Entamoeba histolytica in a hamster model.
• To characterize the pathological changes associated with increased virulence.
• To compare experimental abscesses with human amebic abscesses.

Main Methods:

• Serial liver passage of Entamoeba histolytica trophozoites in hamsters.
• Intervening recovery periods in axenic culture between passages.
• Macroscopic and microscopic examination of induced lesions at various time points post-inoculation.

Main Results:

• Multiple liver passages significantly increased Entamoeba histolytica virulence, leading to larger and persistent lesions.
• Early lesions (6 days post-inoculation) showed granulomas, lymphocytes, and trophozoites.
• Later lesions (1-6 weeks post-inoculation) in highly passaged strains evolved into large, fluid-filled abscesses with fibrous walls, resembling human amebic abscesses.

Conclusions:

• Serial liver passage enhances Entamoeba histolytica virulence in hamsters.
• The hamster model can recapitulate the evolution of granulomatous lesions into cavitary abscesses, similar to human amebic abscesses.
• This finding provides valuable insights into the experimental pathogenesis of amebiasis.