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GLOBAL WATER PATHOGEN PROJECTPART THREE. SPECIFIC EXCRETED PATHOGENS: ENVIRONMENTAL ANDEPIDEMIOLOGY ASPECTS
Leonor Chacin-BonillaUniversidad del Zulia: InicioMaracaibo, Venezuela
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Citation:Chacin-Bonilla, L. 2017. Cyclospora Cayetanensis. In: J.B. Rose and B. Jimnez-Cisneros, (eds) Global WaterPathogens Project. http://www.waterpathogens.org (R.Fayer and W. Jakubowski, (eds) Part 3Protists) http://www.waterpathogens.org/book/cyclospora-cayetanensis Michigan State University, E. Lansing,MI, UNESCO.Acknowledgements: K.R.L. Young, Project Design editor; Website Design (http://www.agroknow.com)
Published: January 15, 2015, 11:58 am, Updated: July 27, 2017, 10:28 am
Cyclospora cayetanensis is recognized as an emergingprotist that causes diarrheal illness and significantlycontributes to the burden of gastroenteritis worldwide. Thischapter summarizes the current status of knowledge ofthe parasite focusing on its public health impact andcontrol strategies. Challenges and limitations forcontrolling the parasite are discussed.
Cyclospora cayetanensis is an apicomplexan coccidium inthe family Eimeriidae closely related to Eimeria species.The parasite is endemic in tropical areas but reportedworldwide. Humans are the only hosts known. Cyclosporais responsible for significant morbidity in children and AIDSpatients and an important cause of foodborne outbreaks.Young children, older adults, and the immunocompromisedare more susceptible to disease.
Globalization of the food supply and increased world travelhave contributed to the spread of the parasite to non-endemic areas. Most of the cases have been linked withtravelers or foodborne outbreaks. Berries and leafy greenvegetables have been implicated as food sources.Consumption of fruits and raw vegetables, drinkinguntreated water, swimming in rivers, contact with soil oranimals, agricultural occupation, and no hand washing havebeen associated with infection. Cyclospora has beenisolated from fruits, vegetables, shellfish, drinking water,swimming pools, lakes, rivers, wastewater, sewage water,and soil. The oocysts are highly resistant to environmentalconditions, pesticides, and disinfectants.
Cyclospora oocysts can be identified using microscopy, andmolecular methods. Techniques for fingerprinting analysisand genotype discrimination are not available. The lack ofan animal model and limited DNA sequence data havehampered efforts to develop detection methods. Thecomplete apicoplast and mitochondrial genomes of C.cayetanensis were recently obtained which could facilitatethe development of genotyping tools.
Prevention and control measures include improvement ofpersonal hygiene, efficient sanitation, and improved waterquality management. Food safety training worldwide isnecessary. Quantifying risk and controlling Cyclospora inthe environment are complicated by the low infectiousdose, the highly resistant oocysts, and the longersporulation and pre-patent periods.
Cyclospora cayetanensis is the only known species ofthe genus Cyclospora to infect humans. Infection results inenteric disease, primarily diarrhea, but asymptomaticinfection has been observed. This protozoan parasite is afecal-oral pathogen in which the oocyst from excreta mustmature in the environment (eg sewage, water or soil) tobecome infectious. About 40% of oocysts sporulate and
become infectious within 14 days at temperatures between23 and 32C (Ortega et al., 1994) To date no animalreservoir hosts are known. Transmission appears to beprimarily foodborne through fresh fruits and vegetablesalthough contact with human fecally contaminatedirrigation water, drinking water, recreational water,sewage, and soil has been documented. Exposure to C.cayetanensis in non- endemic locations has increased inparallel with the globalization of the food supply, increasedconsumption of fresh foods, human migration, andincreased world travel. The opening of new markets forfresh fruits and vegetables from endemic areas where cropsare grown has transformed food consumption patternsresulting in consumption of raw or undercooked foodspotentially exposing consumers to pathogenic contaminantsincluding C. cayetanensis. Seasonal variation in theprevalence of cyclosporiasis may be influenced by factorssuch as rainfall, temperature, and humidity. Climatechange is likely to influence the exposure to the parasite.
Water sanitation is essential to control the transmissionof cyclosporiasis in both developed and developingcountries as well as improved hygiene associated with foodsafety. A better global understanding of this parasite andthe hazard analysis and critical control points (HACCP)arrangements could play a significant role in the control ofCyclospora (Buisson et al., 2008). In industrializedcountries, surveillance of foodborne diseases has become afundamental component of food safety systems(Gervelmayer et al., 2008).
1.0 Epidemiology of the Disease and Pathogen
1.1 Global Burden of Disease
1.1.1 Global distribution
Cyclospora cayetanensis infection has been foundworldwide, in developed and developing countries and inurban and rural areas but is most common in tropical andsubtropical areas (Ortega, 1998). The first documentedcases were found in Papua, New Guinea in 1977 and 1978(Ashford, 1979).
In endemic countries, large-scale surveillance studies ofapparently immunocompetent individuals have reportedCyclospora infection rates from 0 to 41.6% (Table1). Inimmunocompromised patients, mostly HIV/AIDS patientswith diarrhea, the percentages of Cyclospora infectionshave ranged from 0 to 36% (Chacin-Bonilla et al., 2001,2006, 2010). In Colombia, Saudi Arabia, Malaysia,Tanzania, and Cameroon, infection rates of 2.6, 5.9, 4.9,1.2, and 3.6%, respectively, have been found (Arzuza et al.,2003; Al-Megrin, 2010; Asma et al., 2011; Cegielski et al.1999; Nsagha et al., 2016).Variations in prevalence ofinfection may be influenced by study design, geographicarea, age, and immunologic status of the populationstudied, seasonal variability of the parasite, methods ofdetection used, and expertise of the microscopist.
Table 1. Selected reports of Cyclospora prevalence in immunocompetent individuals from developing countries
Area Population Infected Percentage(# of samples) Reference
Bangladesh 2 to 5 yr 0%(0/289) Haque et al., 2003
Brazil All ages 10.8%(9/83) Das-Borges et al., 2009
China All ages 5.6%(10/178) Wang et al., 2002
China Children 0%(0/252)a Liu et al., 2014
Cuba 0 to 7 yr 4.4%(5/113) Nuez et al., 2003
Egypt All ages 9.2%(12/130) Nassef et al., 1998
Guatemala All ages 2.3%(126/5,552) Bern et al., 1999
Guatemala Farm familiesb 3.3%(6/182) Bern et al., 1999
Haiti All ages 6.0%(24/402) Lpez et al., 2003
Honduras All ages 2%(96/4,698) Kaminsky, 2002
India All ages 10.6%(33/310) Gupta, 2011
Indonesia School children 0.6%(2/348) Fryauff et al., 1999
Jordan All ages 6%(12/200) Nimri, 2003
Lao PDR All ages 0.1%(1/686) Kimura et al., 2005
Mexico Children 3.3%(9/272) Daz et al., 2003
Mexico Children 0.6%(60/8,877) Orozco-Mosqueda, 2014
Morocco School children 3.3%(22/673) El Fatni, 2014
Nepal All ages 9.2%(128/1,397) Kimura et al., 2005
Nepal School children 1.6%(23/1,392) Tandukar et al., 2013
Nepal School children 3.9%(20/507) Bhandari et al., 2015
Nigeria All ages 1%(11/1,109) Alakpa et al., 2003
Peru 0 to 2.6 yr 10.9%(41/377)