The course of infection of Encephalitozoon cuniculi genotype I in mice possess combination of features reported in genotypes II and III

Exp Parasitol. 2021 May;224:108101. doi: 10.1016/j.exppara.2021.108101. Epub 2021 Mar 25.


Out of three genotypes of Encephalitozoon cuniculi (I-III) available for experimental studies, E. cuniculi genotype I remains the less characterized. This study describes for the first time individual phases of microsporidiosis caused by E. cuniculi genotype I and efficacy of albendazole treatment in immunocompetent BALB/c and C57Bl/6 mice and immunodeficient SCID, CD4-/- and CD8-/- mice using molecular detection and quantification methods. We demonstrate asymptomatic infection despite an intense dissemination of microsporidia into most organs within the first weeks post infection, followed by a chronic infection characterized by significant microsporidia persistence in immunocompetent, CD4-/- and CD8-/- mice and a lethal outcome for SCID mice. Albendazole application led to loss E. cuniculi genotype I infection in immunocompetent mouse strains, decreased spore burden by half in CD4-/- and CD8-/- mice, and prolongation of survival of SCID mice. These results showed Encephalitozoon cuniculi genotype I infection extend and albendazole sensitivity was comparable to E. cuniculi genotype II, but the infection onset speed and mortality rate was similar to E. cuniculi genotype III. These imply that differences in the course of infection and the response to treatment depend not only on immunological status of the host, but also on the genotype causing the infection.

Keywords: Encephalitozoon cuniculi genotype I; Experimental infection; Laboratory mice; RT PCR quantification.

MeSH terms

  • Albendazole / administration & dosage
  • Animals
  • Anti-Infective Agents / administration & dosage
  • CD4 Antigens / genetics
  • CD8 Antigens / genetics
  • Encephalitozoon cuniculi / classification*
  • Encephalitozoon cuniculi / genetics
  • Encephalitozoonosis / immunology
  • Encephalitozoonosis / parasitology*
  • Genotype
  • Immunocompetence
  • Mice
  • Mice, Inbred BALB C
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Mice, SCID
  • Polymerase Chain Reaction
  • Real-Time Polymerase Chain Reaction


  • Anti-Infective Agents
  • CD4 Antigens
  • CD8 Antigens
  • Albendazole