Page 79 - Medical Parasitology_ A Textbook ( PDFDrive )

72 8 Microsporidia

Fig. 8.1 Microsporidia
spores (band is seen
across the microsporidia
spore stained with Gram
Chromotrope Kinyoun)

Life Cycle (Fig. 8.2)

(1) Infection in host is acquired by ingestion or inhalation of spores. (2–3) In the
duodenum, the spore with its nuclear material is injected through the polar tubule
into the host cell. (4–5) Inside the cell, the microsporidia multiply by repeated
binary fission and produce large number of spores. (6) The spores are then liberated
free from the host cell and infect other cells.

Pathogenesis and Clinical Features

Microsporidia can cause a wide range of illness in patients with HIV, organ trans-
plant recipient, and other immunocompromised diseases. In patients with AIDS,
Enterocytozoon bieneusi and Encephalitozoon intestinalis cause protracted and
debilitating diarrhoea. E. intestinalis may also cause sinusitis, cholangitis and bron-
chiolitis. Modes of transmission are foodborne, waterborne and zoonosis.

Diagnosis

1. Microscopic examination
Diagnosis is made by detection of spores in stool or small intestine biopsy
specimen. The spores can be stained with modified trichrome stain or Gram-
chromotrope kinyoun. Although spores can be visualized by light microscopy,
electron microscopy is the gold standard.
2. Immunofluorescent method using monoclonal antibody
Detection of microsporidia in clinical samples.
3. Molecular diagnosis
PCR on stool specimen.