Microsporidiosis pathophysiology

Microsporidiosis Microchapters
Home
Patient Information
Overview
Historical perspective
Classification
Pathophysiology
Causes
Differentiating Microsporidiosis from other Diseases
Epidemiology and Demographics
Risk Factors
Natural History, Complications and Prognosis
Diagnosis
History and Symptoms
Physical Examination
Laboratory findings
X ray
CT
MRI
Other imaging studies
Other Diagnostic Studies
Treatment
Medical Therapy
Surgery
Primary Prevention
Secondary Prevention
Cost-Effectiveness of Therapy
Future or Investigational Therapies
Case Studies
Case #1
Microsporidiosis pathophysiology On the Web
Most recent articles
Most cited articles
Review articles
CME Programs
Powerpoint slides
Images
American Roentgen Ray Society Images of Microsporidiosis pathophysiology All Images X-rays Echo & Ultrasound CT Images MRI
Ongoing Trials at Clinical Trials.gov
US National Guidelines Clearinghouse
NICE Guidance
FDA on Microsporidiosis pathophysiology
CDC on Microsporidiosis pathophysiology
Microsporidiosis pathophysiology in the news
Blogs on Microsporidiosis pathophysiology
Directions to Hospitals Treating Microsporidiosis
Risk calculators and risk factors for Microsporidiosis pathophysiology

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Pathophysiology

Microbiology

At least 15 microsporidian species have been recognized as human pathogens, spread across eight genera:

• Anncaliia (formerly Brachiola)
  • A. algerae, A. connori, A. vesicularum
• Encephalitozoon
  • E. cuniculi, E. hellem, E. intestinalis (formerly Septata intestinalis)
• Enterocytozoon
  • E. bieneusi
• Microsporidium
  • M. ceylonensis, M. africanum
• Nosema
  • N. ocularum
• Pleistophora sp.
• Trachipleistophora
  • T. hominis, T. anthropophthera
• Vittaforma
  • V. corneae.
• Tubulinosema
  • T. acridophagus

Life Cycle

The infective form of microsporidia is the resistant spore and it can survive for an exteneded period of time in the environment.

1. The spore extrudes its polar tubule and infects the host cell.
2. The spore injects the infective sporoplasm into the eukaryotic host cell through the polar tubule.
3. Inside the cell, the sporoplasm undergoes extensive multiplication either by merogony (binary fission) or schizogony (multiple fission).
4. This development can occur either in direct contact with the host cell cytoplasm (E. bieneusi) or inside a vacuole called a parasitophorous vacuole (E. intestinalis). Either free in the cytoplasm or inside a parasitophorous vacuole, microsporidia develop by sporogony to mature spores.
5. During sporogony, a thick wall is formed around the spore, which provides resistance to adverse environmental conditions. When the spores increase in number and completely fill the host cell cytoplasm, the cell membrane is disrupted and releases the spores to the surroundings.
6. These free mature spores can infect new cells thus continuing the cycle.