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Pathogenicity of axenically cultivated Entamoeba histolytica, strain 200:NIH, in the hamster
Abstract:
Entamoeba histolytica strain 200:NIH cultured axenically for about 15 years produced lesions and abscesses in inbred adult hamsters following intrahepatic, intraperitoneal, and intradermal inoculation. These amebae, even in much higher doses, inoculated into the ceca of adult and young hamsters failed to produce lesions or to become established there. On the other hand, 200:NIH axenic amebae passaged through hamster liver (substrain 200:NIH-L) were able to become established and to produce lesions in the ceca of very young hamsters (1- and 3-week-old), the degree of pathogenicity appearing to be inversely proportional to age of the hamster.
Insights
Entamoeba histolytica strain 200:NIH caused disease in hamsters after liver passage. Young hamsters were more susceptible to cecal infections, indicating age-dependent pathogenicity of this parasite.
Area of Science:
- Medical Parasitology
- Infectious Diseases
- Microbiology
Background:
- Entamoeba histolytica is an important human pathogen.
- Axenic culture of Entamoeba histolytica can alter its virulence.
- Understanding factors influencing Entamoeba histolytica pathogenicity is crucial for disease control.
Purpose of the Study:
- To investigate the pathogenicity of axenically cultured Entamoeba histolytica strain 200:NIH in hamsters.
- To determine the effect of liver passage on the virulence of Entamoeba histolytica.
- To assess the role of host age in susceptibility to Entamoeba histolytica infection.
Main Methods:
- Axenic culture of Entamoeba histolytica strain 200:NIH.
- Inoculation of hamsters via intrahepatic, intraperitoneal, intradermal, and cecal routes.
- Passage of Entamoeba histolytica through hamster liver to create substrain 200:NIH-L.
- Evaluation of lesion development and parasite establishment in hamsters of different ages.
Main Results:
- Entamoeba histolytica strain 200:NIH produced lesions and abscesses in adult hamsters after inoculation into the liver, peritoneum, and dermis.
- The same strain failed to establish infection or cause lesions in the ceca of adult and young hamsters.
- Substrain 200:NIH-L, derived from liver passage, successfully established infection and caused cecal lesions in very young hamsters (1- and 3-week-old).
- Pathogenicity was inversely proportional to hamster age.
Conclusions:
- Liver passage significantly enhanced the virulence of Entamoeba histolytica strain 200:NIH.
- Young hamsters are highly susceptible to cecal infection by virulent Entamoeba histolytica.
- Host age is a critical factor in determining the outcome of Entamoeba histolytica infections.