Microsporidia - Clinical Manifestation, Prognosis, Epidemiology, Reservoir, Lab diagnosis, Treatment

Clinical manifestation of Microsporidia

Microsporidia is an opportunistic parasite that usually affects immunocompromised individuals while infection in immunocompromised individuals is uncommon. The clinical manifestation of Microsporidia includes

• intestinal microsporidiasis

• disseminated microsporidiosis

• ocular infection

• musculoskeletal infection

Intestinal microsporidiasis

• Enterocytozoon bieneusi causes 90% of intestinal microsporidiosis

• Encephalitozoon intestinalis is responsible for 10% of cases

• intestinal microsporidiasis is usually seen in patients with AIDS (CD4 <100mm3)

• characteristics include protracted debilitating chronic diarrhea (lasts several months), malabsorption, and wasting

• the mortality rate is high as 56% in individuals with diarrhea

Disseminated microsporidiosis

• Encephalitozoon intestinalis causes the dissemination of microsporidiosis

  dissemination can involve ocular, genitourinary, and respiratory tracts

  in advanced cases, ocular infections, respiratory infections, and renal failure occurs

• Enterocytozoon bieneusi causes acalculous cholecystitis

• Encephalitozoon hellem and Encephalitozoon cuniculi can produce clinical manifestations such as keratoconjunctivitis, respiratory tract infection, genitourinary tract infection as well as disseminated infections

Ocular infection

• Vittaforma corneae, Nosema connori, and Nosema ocularum cause ocular infection

• this condition manifests as a foreign body sensation, eye redness, excessive lacrimation, and blurred or decreased vision

• cornea infection is caused by Microsporidium ceylonensis and Microsporidium africanum

Musculoskeletal infection

• clinical syndromes include myalgia, fever, generalized muscle weakness

• musculoskeletal infection is caused by Pleistophora and Trachipleistophora hominis

Prognosis of Microsporidia

In severely immunocompromised individuals and in cases of disseminated microsporidiosis, the prognosis is poor.

Epidemiology of Microsporidia

Epidemiologically, Microsporidia is cosmopolitan in distribution. Human infections have been reported in both developed and underdeveloped nations- in immunocompromised as well as immunocompetent individuals.

Reservoir, Source, Transmission of Microsporidia

Spores are the infectious stage of Microsporidia.

Transmission occurs via inhalation or ingestion of spores.

Laboratory Diagnosis of Microsporidia

The laboratory diagnosis of Microsporidia is based on the demonstration of spores in the specimen.

Sample

• stool

• urine

• mucous smears

• biopsy/autopsy tissue

Microscopy

• stains including modified trichrome stains (chromotrope 2R), fluorochrome stains (calcofluor white, Uvitex 2B) can be used for microscopy

• if a modified trichrome stain is used the parasite appears small, oval, refractile spores with bright pinkish-red walls

  a belt-like stripe, stained pink, may also be visible in the middle of the spore

  the spore retains dark violet and the belt-like stripe is enhanced by the rapid Gram chronotrope method

• other stains such as Warthin-Starry silver stain, Brown Brenn Gram stain, Giemsa stain, and trichrome clue can be used to detect spores microscopically in biopsy or autopsy tissue samples

• use of monoclonal and/or polyclonal antibodies in a direct fluorescent method can demonstrate spores as well as extruded polar tubules

• Transmission electron microscopy is the gold standard for the diagnosis and identification of Microsporidia but is expensive and time-consuming

Serodiagnosis

There are no serological tests for laboratory diagnosis of Microsporidia.

Molecular diagnosis

PCR can be used for the molecular diagnosis and species identification of Microsporidia.

Treatment of Microsporidia

• Albendazole can be administered for the treatment of intestinal, disseminated, and ocular microsporidiosis