Microsporidiosis

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Microsporidiosis
Other names: Microsporidiasis[1]
  • Top:Map of microsporidia infection in HIV-infected people worldwide[2]
  • Bottom:1-6)Life cycle of the various organisms that cause microsporidiosis.
SpecialtyInfectious disease
SymptomsDiarrhea, encephalitis,ocular infection[3]
CausesDifferent species of microsporidia[4]
Risk factorsIntravenous drug use, HIV[4]
Diagnostic methodStool exam[4]
Differential diagnosisGiardiasis, bacterial gastroenteritis, Cystoisosporiasis, Cytomegalovirus,Inflammatory bowel disease[4]
Treatmentalbendazole , fumagillin[4]
FrequencyOverall global prevalence is 10.2%[5]

Microsporidiosis is an opportunistic intestinal infection that causes diarrhea and wasting in immunocompromised individuals (HIV, for example). It results from different species of microsporidia, a group of microbial (unicellular) fungi.[6][7]

In HIV infected individuals, microsporidiosis generally occurs when CD4+ T cell counts fall below 150.[8]

Microsporidia have emerged with significant mortality risk in immunocompromised individuals. These are small, single-celled, obligately intracellular parasites linked to water sources as well as wild, and domestic animals.[9] They were once considered protozoans or protists, but are now known to be fungi,[10] or a sister group to fungi; the most common causes of microsporidiosis is Enterocytozoon bieneusi and Encephalitozoon intestinalis.[11][4]

Signs and symptoms

The clinical presentation of this infection is as follows:[3]

Cause

Enterocytozoon bieneusi [12]

The primary causes are Enterocytozoon bieneusi and Encephalitozoon intestinalis.[13] At least 15 microsporidian species have been recognized[14] as human pathogens, spread across nine genera:

Risk factors

In terms of the risk factors for Microsporidiosis we find the following:[4]

Transmission

Groundwater may be extracted through a water well

As to transmission of Histoplasmosis we find the following:[4]

Mechanism

In terms of the life cycle of Microsporidiosis we find the following :[4][12]

  • The infective form of microsporidia is the resistant spore and it can survive for an extended period of time in the environment.
  • The spore extrudes its polar tubule and infects the host cell.
  • The spore injects the infective sporoplasm into the eukaryotic host cell through the polar tubule.
  • Inside the cell, the sporoplasm undergoes extensive multiplication either by merogony (binary fission) or schizogony (multiple fission).
  • 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.
  • 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.
  • These free mature spores can infect new cells thus continuing the cycle.

Diagnosis

a) Stool smear - microsporidial spores arrow b) stool smear -spores of microsporidia arrow c) PCR product agarose gel electrophoresis

In terms of diagnosis for Microsporidiosis we find that using PCR in one of the available options.[4]

Diagnosis with Microsporidia can be done through gram-positive, acid-fast spores in stool and biopsy material with morphologic demonstration of the organism. Initial detection through light microscopic examination of tissue sections, stools, duodenal aspirates, nasal discharges, bronchoalveolar lavage fluids, and conjunctival smears.[15] Definitive diagnosis can also be achieved through fluorescein-tagged antibody immunofluorescence or electron microscopy.[15][16]

Differential diagnosis

The DDx of Microsporidiosis in an affected individual is as follows:[4]

Classification

Although it is classified as a protozoal disease in ICD-10, their phylogenetic placement has been resolved to be within the Fungi, and some sources classify microsporidiosis as a mycosis,[17] however, they are highly divergent and rapidly evolving.[18][19][20]

Treatment

Fumagillin has been used in the treatment,[13][21] another agent used is albendazole.[22]

Because of its severe mortality risk in immunocompromised individuals, the two main agents used find that the mechanism of action of albendazole, inhibits tubulin, while fumagillin mode of action, inhibits methionine aminopeptidase type two.[23]

  • Fumagillin structure

    Fumagillin structure

  • Albendazole

    Albendazole

Prognosis

In short the prognosis for Microsporidiosis is good. However , in immunocompromised individuals, such as HIV/AIDS, organ transplant recipients, or those on immunosuppressive therapy, the prognosis is not as favorable.[24][4]

Epidemiology

In terms of the epidemiology, we find that prevalence rates vary significantly. Studies indicate the prevalence can go from 0 to 50 percent, influenced by geographic region, and the demographics of population. Higher prevalence rates have been observed in specific groups, such as immunocompromised individuals.[5][25]

  • World geographic prevalence of microsporidia.[5]

    World geographic prevalence of microsporidia.[5]

  • a-d)Summary of global microsporidia prevalence[5]

    a-d)Summary of global microsporidia prevalence[5]

Microsporidiosis is common in 92 countries, with the higher prevalence in the region of Northern Europe and the country of South Africa.[5][25]

History

Microsporidiosis was first described by Félix Balbiani in 1882. He identified microsporidia as a group of spore-forming unicellular parasites. Initially, they were considered protozoa, but later research reclassified them as fungi or a sister group to true fungi.[4]

References

  1. ↑ "Microsporidiosis (Concept Id: C0085407) - MedGen - NCBI". www.ncbi.nlm.nih.gov. Retrieved 10 December 2024.
  2. ↑ Wang, Ze-Dong; Liu, Quan; Liu, Huan-Huan; Li, Shuang; Zhang, Li; Zhao, Yong-Kun; Zhu, Xing-Quan (9 January 2018). "Prevalence of Cryptosporidium, microsporidia and Isospora infection in HIV-infected people: a global systematic review and meta-analysis". Parasites & Vectors. 11 (1): 28. doi:10.1186/s13071-017-2558-x. ISSN 1756-3305. PMC 5759777. PMID 29316950.
  3. ↑ 3.0 3.1 "Microsporidiosis | NIH". clinicalinfo.hiv.gov. Archived from the original on 20 May 2021. Retrieved 23 December 2021. Archived 20 May 2021 at the Wayback Machine
  4. ↑ 4.00 4.01 4.02 4.03 4.04 4.05 4.06 4.07 4.08 4.09 4.10 4.11 4.12 Fadhilah, Araniy; Gabbar, Aishah; Bokhari, Abdullah A. (2024). "Microsporidium". StatPearls. StatPearls Publishing. PMID 30725851. Archived from the original on 2024-02-28. Retrieved 2024-12-09. Archived 2024-02-28 at the Wayback Machine
  5. ↑ 5.0 5.1 5.2 5.3 5.4 Ruan, Yingfei; Xu, Xiaofei; He, Qiang; Li, Li; Guo, Junrui; Bao, Jialing; Pan, Guoqing; Li, Tian; Zhou, Zeyang (1 April 2021). "The largest meta-analysis on the global prevalence of microsporidia in mammals, avian and water provides insights into the epidemic features of these ubiquitous pathogens". Parasites & Vectors. 14 (1): 186. doi:10.1186/s13071-021-04700-x. ISSN 1756-3305. PMID 33794979.
  6. ↑ "Microsporidiosis: Parasitic Infections: Merck Manual Home Health Handbook". Archived from the original on 2015-02-21. Retrieved 2021-09-25. Archived 2015-02-21 at the Wayback Machine
  7. ↑ "Microsporidia Infections (Microsporidiosis)". Red Book: 2024–2027 Report of the Committee on Infectious Diseases. Red Book: 2024–2027 Report of the Committee on Infectious Diseases. 25 April 2024. pp. 601–603. doi:10.1542/9781610027373-S3_012_005. ISBN 978-1-61002-737-3. Retrieved 10 December 2024.
  8. ↑ Justiz Vaillant, Angel A.; Naik, Roopa (2024). "HIV-1–Associated Opportunistic Infections". StatPearls. StatPearls Publishing. PMID 30969609. Archived from the original on 14 July 2023. Retrieved 15 December 2024. Archived 14 July 2023 at the Wayback Machine
  9. ↑ Didier ES, Maddry JA, Brindley PJ, Stovall ME, Didier PJ. Therapeutic strategies for human microsporidia infections. Expert Rev Anti Infect Ther. 2005 Jun;3(3):419-34. doi: 10.1586/14787210.3.3.419. PMID: 15954858.
  10. ↑ Hibbett, D.S.; et al. (2007). "A higher level phylogenetic classification of the Fungi" (PDF). Mycological Research. 111 (5): 509–47. doi:10.1016/j.mycres.2007.03.004. PMID 17572334. Archived (PDF) from the original on 2016-10-20. Retrieved 2021-09-25. Archived 2016-10-20 at the Wayback Machine
  11. ↑ Silar, Philippe (2016). Protistes Eucaryotes : Origine, Evolution et Biologie des Microbes Eucaryotes. HAL. p. 462. ISBN 978-2-9555841-0-1. Archived from the original on 2019-07-02. Retrieved 2021-09-25. Archived 2019-07-02 at the Wayback Machine
  12. ↑ 12.0 12.1 "CDC - DPDx - Microsporidiosis". www.cdc.gov. 29 May 2019. Archived from the original on 5 June 2021. Retrieved 7 December 2024.
  13. ↑ 13.0 13.1 Lanternier F, Boutboul D, Menotti J, et al. (February 2009). "Microsporidiosis in solid organ transplant recipients: two Enterocytozoon bieneusi cases and review". Transpl Infect Dis. 11 (1): 83–8. doi:10.1111/j.1399-3062.2008.00347.x. PMID 18803616.
  14. ↑ "CDC - DPDx - Microsporidiosis". www.cdc.gov. 2017-12-29. Archived from the original on 2021-06-05. Retrieved 2018-01-04. Archived 2021-06-05 at the Wayback Machine
  15. ↑ 15.0 15.1 Weber R, Bryan RT, Schwartz DA, Owen RL. Human microsporidial infections. Clin Microbiol Rev. 1994 Oct;7(4):426-61. doi: 10.1128/cmr.7.4.426. PMID: 7834600; PMCID: PMC358336.
  16. ↑ Kock NP, Petersen H, Fenner T, Sobottka I, Schmetz C, Deplazes P, Pieniazek NJ, Albrecht H, Schottelius J. Species-specific identification of microsporidia in stool and intestinal biopsy specimens by the polymerase chain reaction. Eur J Clin Microbiol Infect Dis. 1997 May;16(5):369-76. doi: 10.1007/BF01726365. PMID: 9228477.
  17. ↑ Microsporidiosis at the US National Library of Medicine Medical Subject Headings (MeSH)
  18. ↑ Didier ES (April 2005). "Microsporidiosis: an emerging and opportunistic infection in humans and animals". Acta Trop. 94 (1): 61–76. doi:10.1016/j.actatropica.2005.01.010. PMID 15777637.
  19. ↑ Keeling PJ, Luker MA, Palmer JD (January 2000). "Evidence from beta-tubulin phylogeny that microsporidia evolved from within the fungi". Mol. Biol. Evol. 17 (1): 23–31. doi:10.1093/oxfordjournals.molbev.a026235. PMID 10666703.
  20. ↑ Keeling PJ; Madhani, Hiten D. (September 2009). Madhani, Hiten D. (ed.). "Five Questions about Microsporidia". PLOS Pathogens. 5 (9): e1000489. doi:10.1371/journal.ppat.1000489. PMC 2742732. PMID 19779558.
  21. ↑ Molina JM, Tourneur M, Sarfati C, et al. (June 2002). "Fumagillin treatment of intestinal microsporidiosis". N. Engl. J. Med. 346 (25): 1963–9. doi:10.1056/NEJMoa012924. PMID 12075057.
  22. ↑ Didier ES, Maddry JA, Brindley PJ, Stovall ME, Didier PJ (June 2005). "Therapeutic strategies for human microsporidia infections". Expert Rev Anti Infect Ther. 3 (3): 419–34. doi:10.1586/14787210.3.3.419. PMID 15954858.
  23. ↑ Han B, Weiss LM. Therapeutic targets for the treatment of microsporidiosis in humans. Expert Opin Ther Targets. 2018 Nov;22(11):903-915. doi: 10.1080/14728222.2018.1538360. Epub 2018 Nov 1. PMID: 30336698; PMCID: PMC6300147.
  24. ↑ "Microsporidiosis - Infectious Diseases". MSD Manual Professional Edition. Archived from the original on 13 June 2024. Retrieved 16 December 2024. Archived 13 June 2024 at the Wayback Machine
  25. ↑ 25.0 25.1 Han, Bing; Pan, Guoqing; Weiss, Louis M. (30 June 2021). "Microsporidiosis in Humans". Clinical Microbiology Reviews. 34 (4): e00010–20. doi:10.1128/CMR.00010-20. PMC 8404701. PMID 34190570.

External links

Classification
External resources
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