Cyclospora cayetanensis: Difference between revisions
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Revision as of 18:42, 30 July 2015
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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
Cyclospora cayetanensis is a protozoan that causes disease in humans, and possibly in other primates. It has also been isolated from the feces of other animals such as ducks and chickens. Due to the spherical shape of C. cayetanensis sporocytes, it was placed in the Cyclospora genus. It has a double layered wall that gives it resistance against disinfectants and adhesins which are responsible for its adherence characteristics. The bacteria show tropism for epithelial cells of the small intestine, especially of the duodenum and jejunum.
Taxonomy
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Eukaryota; Alveolata; Apicomplexa; Conoidasida; Coccidia; Eucoccidiorida; Eimeriorina; Eimeriidae; Cyclospora[3]
Biology
Cyclospora cayetanensis is an obligate intracellular apicomplexan, cyst-forming coccidian protozoan, of the family of Eimeriidae, which commonly causes self-limiting diarrhea. Morphologically C. cayetanensis has spherical oocysts that are between 7.5 and 10 micrometers in diameter that also have a 50 nanometer thick bilayered wall with an outer threadlike coat that has been called a wrinkle by some researchers.[4][5][6]
According to a phylogenetic analysis performed with the 18S rRNA gene, in the Cyclospora species isolated from a group of baboons, this species, although different, was proved to be similar to the C. cayetanensis that infects humans. These two species were then documented was belonging to the same clade of the Eimeria species.[7] Other three species of Cyclospora were also identified in non-human primates and characterized with the SSU rRNA analysis, later that year. Because there are morphologically similar, there can not be differentiated by light microscopy.[8] These species: C. cercopitheci, C. colobi and C. papionis were identified in green monkeys, colobus monkeys, and baboons, respectively. C. cayetanensis and these three other species of Cyclospora all share the characteristic of being host-specific.[5][5]
It is not known the exact conditions and location required for the sporulation of oocysts in the natural environment, however, these data would help to understand and predict the distribution and seasonality of C. cayetanensis. Due to its double-layered wall it is highly resistant, particularly to disinfectants used during food processing. This resistance along with its binding affinity to certain produce, explains the risks associated with contaminated foods. The adhesive properties of C. cayetanensis are stronger than those of the oocysts of Giardia or Cryptosporidium, however, the responsible adhesins are yet to be identified.[5]
Tropism
Cyclospora cayetanensis shows tropism for epithelial cells of the small intestine, especially for the jejunum.[5]
Natural Reservoir
C. cayetanensis is an host specific parasite that is able to infect humans. Cyclospora oocysts have also been isolated from the feces of several animals, such as ducks, chickens and dogs.[9][10][11] Attempts to identify and to infect different animals with C. cayetanensis have failed.[12] Certain shellfish may acquire C. cayetanensis from contaminated waters, and concentrate its oocyst for several days.[13]
Treatment
Antimicrobial Regimen
- Cyclospora cayetanensis[14]
- Preferred regimen: Trimethoprim-sulfamethoxazole one double-strength tablet PO bid for 7-10 days
- Alternative regimen(1): Ciprofloxacin 500 mg PO bid for 7 days
- Alternative regimen(2): Nitazoxanide 500 mg PO bid for 7 days
- Note(1): One double-strength tablet (160 mg TMP/800 mg SMX) .
- Note(2): Treatment is continued for 7 days in immunocompetent hosts and for 7 to 10 days in patients with HIV infection.
References
- ↑ "http://phil.cdc.gov/phil/details.asp". External link in
|title=(help) - ↑ "http://phil.cdc.gov/phil/details.asp". External link in
|title=(help) - ↑ "Cyclospora cayetanensis".
- ↑ "Cyclosporiasis".
- ↑ 5.0 5.1 5.2 5.3 5.4 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.
- ↑ Ortega YR, Gilman RH, Sterling CR (1994). "A new coccidian parasite (Apicomplexa: Eimeriidae) from humans". J Parasitol. 80 (4): 625–9. PMID 8064531.
- ↑ Lopez FA, Manglicmot J, Schmidt TM, Yeh C, Smith HV, Relman DA (1999). "Molecular characterization of Cyclospora-like organisms from baboons". J Infect Dis. 179 (3): 670–6. doi:10.1086/314645. PMID 9952374.
- ↑ Eberhard ML, da Silva AJ, Lilley BG, Pieniazek NJ (1999). "Morphologic and molecular characterization of new Cyclospora species from Ethiopian monkeys: C. cercopitheci sp.n., C. colobi sp.n., and C. papionis sp.n." Emerg Infect Dis. 5 (5): 651–8. doi:10.3201/eid0505.990506. PMC 2627716. PMID 10511521.
- ↑ García-López HL, Rodríguez-Tovar LE, Medina-De la Garza CE (1996). "Identification of Cyclospora in poultry". Emerg Infect Dis. 2 (4): 356–7. doi:10.3201/eid0204.960414. PMC 2639917. PMID 8969254.
- ↑ Zerpa R, Uchima N, Huicho L (1995). "Cyclospora cayetanensis associated with watery diarrhoea in Peruvian patients". J Trop Med Hyg. 98 (5): 325–9. PMID 7563260.
- ↑ Yai LE, Bauab AR, Hirschfeld MP, de Oliveira ML, Damaceno JT (1997). "The first two cases of Cyclospora in dogs, São Paulo, Brazil". Rev Inst Med Trop Sao Paulo. 39 (3): 177–9. PMID 9460261.
- ↑ 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.
- ↑ Graczyk TK, Ortega YR, Conn DB (1998). "Recovery of waterborne oocysts of Cyclospora cayetanensis by Asian freshwater clams (Corbicula fluminea)". Am J Trop Med Hyg. 59 (6): 928–32. PMID 9886202.
- ↑ Bennett, John (2015). Mandell, Douglas, and Bennett's principles and practice of infectious diseases. Philadelphia, PA: Elsevier/Saunders. ISBN 978-1455748013.