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''C. cayetanensis'' oocysts have also been isolated from non gastrointestinal sites, namely from sputum of immunocompromised patients with HIV and concomitant TB.  This leads to hypothesis that ''C. cayetanensis'' may be an opportunistic pathogen.<ref name="pmid10810327">{{cite journal| author=Di Gliullo AB, Cribari MS, Bava AJ, Cicconetti JS, Collazos R| title=Cyclospora cayetanensis in sputum and stool samples. | journal=Rev Inst Med Trop Sao Paulo | year= 2000 | volume= 42 | issue= 2 | pages= 115-7 | pmid=10810327 | doi= | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=10810327  }} </ref>
''C. cayetanensis'' oocysts have also been isolated from non gastrointestinal sites, namely from sputum of immunocompromised patients with HIV and concomitant TB.  This leads to hypothesis that ''C. cayetanensis'' may be an opportunistic pathogen.<ref name="pmid10810327">{{cite journal| author=Di Gliullo AB, Cribari MS, Bava AJ, Cicconetti JS, Collazos R| title=Cyclospora cayetanensis in sputum and stool samples. | journal=Rev Inst Med Trop Sao Paulo | year= 2000 | volume= 42 | issue= 2 | pages= 115-7 | pmid=10810327 | doi= | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=10810327  }} </ref>
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Thus far, C. cayetanensis infections have been identified only in humans. The role of other animal species as reservoirs or inter- mediary hosts has been examined, with conflicting results. Cyclo- spora oocysts have been found in feces of chickens (37, 62, 70), ducks (62, 197), and dogs (27, 37, 62, 194) collected in countries where Cyclospora is endemic (27, 62, 63). However, attempts to experimentally infect a variety of animals (63) and humans (5) have been unsuccessful. The presence of Cyclospora in stools from animals could be explained by eating or coprophagic habits of the surveyed animals. Nonetheless, it cannot yet be ruled out that animals may play a role in the dissemination of Cyclospora by contaminating water and food products. Two reports indicate that Cyclospora can be propagated in guinea pigs (191) and albino mice (162). These studies could not be reproduced, and further analyses are needed to determine the susceptibility of these ani- mals to infection by Cyclospora and their suitability as hosts or reservoirs of C. cayetanensis.
Insects, rotifers, and free-living nematodes could also play a role in the dissemination of oocysts, a phenomenon that has been described for Cryptosporidium (67, 74, 75, 90, 179) and other food-borne pathogens. The nematode Caenorhabditis elegans can ingest and excrete infectious bacteria (23, 98, 99) as well as Cryptosporidium parvum oocysts. Although the oocysts of Cyclospora are larger and may not be ingested by C. elegans, other, larger species of free-living nematodes could have a significant role in Cyclospora oocyst dissemination. Therefore, the role of free-living nematodes and other mechanical vectors in the contamination of produce and other food crops needs to be examined further (90).
Travel to rural areas and ingestion of contami- nated foods could be modes of infection. Accidental inhalation of oocysts has also been suggested (93)
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[[Image:Cyclosporiasis.gif|thumb|center|400 px|Life cycle of Cyclosporiasis<SMALL><SMALL>''[http://www.cdc.gov  - Center for Disease Control and Prevention(CDC)]''<ref name="CDC">{{Cite web | title = Center for Disease Control and Prevention (CDC) | url =  http://www.cdc.gov}}</ref></SMALL></SMALL>]]
[[Image:Cyclosporiasis.gif|thumb|center|400 px|Life cycle of Cyclosporiasis<SMALL><SMALL>''[http://www.cdc.gov  - Center for Disease Control and Prevention(CDC)]''<ref name="CDC">{{Cite web | title = Center for Disease Control and Prevention (CDC) | url =  http://www.cdc.gov}}</ref></SMALL></SMALL>]]

Revision as of 18:27, 18 September 2014

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: João André Alves Silva, M.D. [2]

Overview

Fresh produce and water can serve as vehicles for transmission and the sporulated oocysts are ingested (in contaminated food or water). The oocysts excyst in the gastrointestinal tract, freeing the sporozoites which invade the epithelial cells of the small intestine.

Pathogenesis

Life Cycle

Unsporulated oocysts of Cyclospora cayetanensis are excreted from infected persons. When freshly passed in stool, the oocyst is not infective (thus, direct fecal-oral transmission cannot occur, which differentiates Cyclospora from another important coccidian parasite, Cryptosporidium). Under adequate temperatures (23-32ºC), these take about 7-15 days to sporulate, in order to become infectious. After being ingested, from contaminated water and food, oocysts excyst to release elongated sporozoites. Sporozoites will then infect epithelial cells of the gastrointestinal tract, particularly those of the duodenum and jejunum. The sporozoites undergo asexual reproduction, originating meronts type I and II, which will then differentiate into gametocytes. These last will be fertilized to produce a zygote.[1][2] Inside the cells, zygotes undergo asexual multiplication and sexual development to mature into oocysts, which will be shed in stool.[3]

C. cayetanensis oocysts have also been isolated from non gastrointestinal sites, namely from sputum of immunocompromised patients with HIV and concomitant TB. This leads to hypothesis that C. cayetanensis may be an opportunistic pathogen.[4]

Life cycle of Cyclosporiasis- Center for Disease Control and Prevention(CDC)[3]

Transmission

The protozoan lives out its lifecycle intracellularly within the host’s epithelial cells and gastrointestinal tract. Infection is transmitted through the oral-fecal route, and begins when a person ingests oocysts in fecally contaminated food or water.

  • Fresh produce and water can serve as vehicles for transmission and the sporulated oocysts are ingested (in contaminated food or water).

Microscopic Pathology

References

  1. Eberhard ML, Ortega YR, Hanes DE, Nace EK, Do RQ, Robl MG; et al. (2000). "Attempts to establish experimental Cyclospora cayetanensis infection in laboratory animals". J Parasitol. 86 (3): 577–82. doi:10.1645/0022-3395(2000)086[0577:ATEECC]2.0.CO;2. PMID 10864257.
  2. Ortega YR, Sanchez R (2010). "Update on Cyclospora cayetanensis, a food-borne and waterborne parasite". Clin Microbiol Rev. 23 (1): 218–34. doi:10.1128/CMR.00026-09. PMC 2806662. PMID 20065331.
  3. 3.0 3.1 "Cyclosporiasis".
  4. Di Gliullo AB, Cribari MS, Bava AJ, Cicconetti JS, Collazos R (2000). "Cyclospora cayetanensis in sputum and stool samples". Rev Inst Med Trop Sao Paulo. 42 (2): 115–7. PMID 10810327.

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