The Experts below are selected from a list of 2925 Experts worldwide ranked by ideXlab platform
Ynés R. Ortega - One of the best experts on this subject based on the ideXlab platform.
-
Introduction to Cyclospora cayetanensis : The Parasite and the Disease
SpringerBriefs in Food Health and Nutrition, 2017Co-Authors: Ynés R. Ortega, Lucy J. RobertsonAbstract:Cyclospora cayetanensis is a coccidian parasite that infects humans and causes gastrointestinal illness. Initially considered an agent of travelers’ diarrhea, it has now been identified in individuals residing in non-endemic locations and without travel history. These individuals had often consumed fresh fruits and/or other fresh produce that had been imported from endemic locations. Cyclospora has different characteristics than those of other intestinal protozoan parasites that infect humans. Unlike the protozoan parasites Cryptosporidium and Giardia, which are immediately infectious upon excretion, Cyclospora requires a prolonged sporulation time to fully differentiate and become infectious. Additionally, C. cayetanensis seems to be host-specific and exclusively infectious to humans. The infection occurs in endemic populations at specific months of the year; the environmental conditions required for this seasonality have not been determined. Finally, as with many parasites, Cyclospora seems to be highly resistant to chemical disinfection, although it can effectively killed by heating and prolonged freezing. Throughout this chapter we will review the basic biological characteristics of Cyclospora, and mention some other challenges associated with this parasite that are expanded upon in the other chapters.
-
doi:10.4269/ajtmh.13-0535 Copyright © 2014 by The American Society of Tropical Medicine and Hygiene Cyclospora cayetanensis in a Pediatric Hospital in Morelia, México
2016Co-Authors: Guadalupe E. Orozco-mosqueda, O A. Martı́nez-loya, Ynés R. OrtegaAbstract:Abstract. Cyclospora cayetanensis, a coccidian parasite, can cause gastrointestinal illness in humans and is characterized by watery and persistent diarrhea and abdominal pain. Cyclosporiasis has been associated with traveler’s diarrhea. The infection is acquired through food and waterborne transmission, particularly by consumption of contaminated fresh fruits and vegetables. In the present study, stool samples from 8,877 children were examined for ova and parasites at the Pediatric Hospital of Morelia in Michoacán, Mexico, during 2000–2009. Sixty children (0.67%) had Cyclospora in their stools. Diarrhea (45.8%), abdominal pain (39.6%), and vomiting (18.8%) were the most frequent symptoms of cases with cyclosporiasis. Most of the cases (93.3%) were observed during June–August, the rainy season. In 45 children, Cyclospora was the only parasitic pathogen detected (75%); 15 children were co-infected with commensal, pathogenic, or both groups of parasites. Our findings suggest that C. cayetanensis is endemic to Michoacán and shows characteristically temporal patterns
-
Cyclospora cayetanensis in a Pediatric Hospital in Morelia, Mexico
The American journal of tropical medicine and hygiene, 2014Co-Authors: Guadalupe E. Orozco-mosqueda, Orlando A. Martínez-loya, Ynés R. OrtegaAbstract:Cyclospora cayetanensis, a coccidian parasite, can cause gastrointestinal illness in humans and is characterized by watery and persistent diarrhea and abdominal pain. Cyclosporiasis has been associated with traveler's diarrhea. The infection is acquired through food and waterborne transmission, particularly by consumption of contaminated fresh fruits and vegetables. In the present study, stool samples from 8,877 children were examined for ova and parasites at the Pediatric Hospital of Morelia in Michoacán, Mexico, during 2000-2009. Sixty children (0.67%) had Cyclospora in their stools. Diarrhea (45.8%), abdominal pain (39.6%), and vomiting (18.8%) were the most frequent symptoms of cases with cyclosporiasis. Most of the cases (93.3%) were observed during June-August, the rainy season. In 45 children, Cyclospora was the only parasitic pathogen detected (75%); 15 children were co-infected with commensal, pathogenic, or both groups of parasites. Our findings suggest that C. cayetanensis is endemic to Michoacán and shows characteristically temporal patterns.
-
Synopses Cyclospora: An Enigma Worth Unraveling
2013Co-Authors: Charles R. Sterling, Ynés R. OrtegaAbstract:In part, Cyclospora cayetanensis owes its recognition as an emerging pathogen to the increased use of staining methods for detecting enteric parasites such as Cryptosporidium. First reported in patients in New Guinea in 1977 but thought to be a coccidian parasite of the genus Isospora, C. cayetanensis received little attention until it was again described in 1985 in New York and Peru. In the early 1990s, human infection associated with waterborne transmission of C. cayetanensis was suspected; foodborne transmission was likewise suggested in early studies. The parasite was associated with several disease outbreaks in the United States during 1996 and 1997. This article reviews current knowledge about C. cayetanensis (including its association with waterborne and foodborne transmission), unresolved issues, and research needs. Cyclospora Overview Cyclospora cayetanensis is a protozoan parasite (subphylum Apicomplexa, subclass Coccidiasina, order Eucoccidiorida, family Eimeriidae). The organism’s link to the Eimeriida
-
Update on Cyclospora cayetanensis, a Food-Borne and Waterborne Parasite
Clinical microbiology reviews, 2010Co-Authors: Ynés R. Ortega, Roxana SanchezAbstract:The coccidian parasite Cyclospora cayetanensis is recognized as an emerging pathogen that causes protracted diarrhea in humans. The first cases of Cyclospora infection were reported in the late 1970s and were observed among expatriates and travelers in regions where infections are endemic. Since then, Cyclospora has been considered a cause of traveler's diarrhea. Epidemiological investigations were reported and examined in areas of endemicity even before the true identity of Cyclospora was elucidated. Cyclospora was fully characterized in the early 1990s, but it was not until the 1995 Cyclospora outbreak in the United States and Canada that it caught the attention of the public and physicians. The biology, clinical presentation, epidemiology, diagnosis, treatment, and control of cyclosporiasis are reviewed, with a focus on diagnostic assays currently being used for clinical and environmental samples. Challenges and limitations in working with Cyclospora are also discussed.
Mark L. Eberhard - One of the best experts on this subject based on the ideXlab platform.
-
Cyclospora spp. in drills, Bioko Island, Equatorial Guinea.
Emerging infectious diseases, 2014Co-Authors: Mark L. Eberhard, Jacob R. Owens, Henry S. Bishop, Marcos De Almeida, Alex J. Da SilvaAbstract:To the Editor: More than a decade has passed since major outbreaks of Cyclospora cayetanensis infection in the United States and Canada drew attention to this newly emerging infection (1, 2). Awareness of these infections was highlighted again by large outbreaks in the summer of 2013 (3). However, many questions remain unanswered regarding this organism, including aspects of its life cycle, geographic distribution, and range of related species. In 1999, three new distinct Cyclospora species noted for their close similarity with C. cayetanensis from humans were isolated from monkeys in Ethiopia (4). A survey of primates in Kenya increased awareness of the extended distribution of these 3 species in eastern Africa and provided confirmation of their marked host specificity, even where the ranges of host species overlapped (5). Most recently, C. colobi–like organisms were identified in snub-nosed golden colobus monkeys in northwestern China (6). We report the characterization of Cyclospora spp. recovered from drills (Mandrillus leucophaeus poensis) on Bioko Island, Equatorial Guinea. During January–February 2011 and 2012, fecal samples from free-ranging animals were collected and placed in 10% formalin (2011) or potassium dichromate (2012). Because samples were collected opportunistically from unidentified animals of undetermined age and sex, whether any samples were collected from the same animals in either year was not known. Fecal samples were concentrated by using the formyl ethyl acetate method, and sediment was examined by using fluorescent microscopy to detect oocysts (4). Three (9%) of 26 samples from 2011 and 8 (31%) of 25 samples from 2012 were positive for Cyclospora oocysts that were spherical, measured 8–10 µm in diameter, and showed autofluorescence. The oocysts collected in potassium dichromate had sporulated by the time of examination, which facilitated and confirmed identification as Cyclospora spp. Representative samples from 4 animals in the second collection were submitted for molecular analysis. The entire 18S rRNA gene (1,796 bp) was obtained from 2 DNA fragments amplified by PCR from DNA extracted from 3 fecal specimens by using procedures and primers for genetic analysis of coccidian parasites (4,7,8). Six distinct full-length 18S rRNA sequences were obtained and compared with sequences in GenBank. Although our sequences showed high similarity with 18S rRNA genes for all Cyclospora species, the sequences were most similar to the C. papionis 18S rRNA gene (GenBank accession no. {"type":"entrez-nucleotide","attrs":{"text":"AF111187","term_id":"4406389","term_text":"AF111187"}}AF111187), even though 3 T→C transitions at nucleotides positions 680, 1054, and 1694 were observed. Analyses of these 6 sequences showed intravariation caused mainly by T→C and A→G transitions. Further studies on different species should be performed to verify whether this is a common feature in Cyclospora spp. 18S rRNA genes. This report extends our knowledge of the range of Cyclospora spp. in monkeys to include western Africa and their host range to include an additional distinct primate species. Results of molecular analysis indicate that this Cyclospora sp. isolate from drills on Bioko Island is most similar to C. papionis from baboons in eastern Africa, an observation that is unexpected and somewhat difficult to explain. Previous studies have suggested that different primate hosts harbor distinctly different Cyclospora species (4–6). Baboons are not found on Bioko Island or in mainland Equatorial Guinea near Bioko Island and are allopatric with drills on the mainland. In addition, drills on Bioko Island have been separated from contact with drills on the mainland for 10,000–12,000 years (9), further isolating the ecology of this host–parasite relationship and confusing how C. papionis was established in drills on Bioko Island. Drills are now considered to have closer phylogenetic affinity with mangabeys (Cercocebus spp.) than with baboons (10), although the phylogeny of these primates is not completely resolved. This finding further confuses an explanation of why the parasite isolated from drills would be similar to that recovered from baboons. It could be speculated that C. papionis arrived on Bioko Island from the mainland through some third host, such as collared (red-capped) mangabeys (C. torquatus), which has close phylogenetic relationships and overlapping ranges with drills and baboons. Any such explanation would mean that Cyclospora spp. infected drills before Bioko Island and the mainland separated. Another possibility is that Cyclospora spp. exhibit host–niche specificity. Colobus monkeys, the host for C. colobi, are arboreal folivores, many of which consume relatively difficult-to-digest foods and have large specialized guts. Vervets, hosts for C. cercopitheci, are also arboreal, but have a frugivorous–insectivorous diet and consume little leaf matter. Baboons and drills, hosts for C. papionis, are predominantly terrestrial and have generalist–omnivorous diets and unspecialized guts. These different ecologic and physiologic differences among the 3 species may affect the observed Cyclospora spp. host specificity. Observations in the present study extend our knowledge of the geographic and host range for cyclosporiasis. However, these observations leave several unanswered questions about our understanding of the parasite in nonhuman primates; the evolutionary relationship between human C. cayetanensis and these closely related species in monkeys; what additional monkey host species, especially on Bioko Island, may harbor Cyclospora spp.; and what other as yet unrecognized species of Cyclospora may be infecting primates.
-
Human challenge pilot study with Cyclospora cayetanensis.
Emerging infectious diseases, 2004Co-Authors: Edith M. Alfano-sobsey, Mark L. Eberhard, Eva K. Nace, Kimberly Y. Won, John R. Seed, David J. Weber, Christine L. MoeAbstract:We describe a pilot study that attempted to infect human volunteers with Cyclospora cayetanensis. Seven healthy volunteers ingested an inoculum of Cyclospora oocysts (approximately 200–49,000 oocysts). The volunteers did not experience symptoms of gastroenteritis, and no oocysts were detected in any stool samples during the 16 weeks volunteers were monitored.
-
Epidemiology of Cyclospora cayetanensis and Other Intestinal Parasites in a Community in Haiti
Journal of clinical microbiology, 2003Co-Authors: Adriana S. Lopez, Mark L. Eberhard, Michael J. Arrowood, Jean M. Bendik, Jean Y. Alliance, Jacquelin M. Roberts, Alexandre J. Da Silva, Iaci N. S. Moura, Barbara L. HerwaldtAbstract:We conducted an exploratory investigation in a community in Haiti to determine the prevalence of Cyclospora cayetanensis infection and to identify potential risk factors for C. cayetanensis infection. In 2001, two cross-sectional stool surveys and a nested case-control study were conducted. In 2002, a follow-up cross-sectional stool survey was conducted among children ≤10 years of age. Stool specimens from study participants and water samples from their wells were examined for Cyclospora and other intestinal parasites. In stools, the prevalence of infection with Cyclospora in persons of all ages decreased from 12% (20 of 167 persons) in February 2001 to 1.1% (4 of 352 persons) in April 2001, a 90.8% decrease. For children ≤10 years of age, the prevalence rates were 22.5% (16 of 71 children) in February 2001, 3.0% (4 of 135 children) in April 2001, and 2.5% (2 of 81 children) in January 2002. Use of the water from the artesian well in the northern region of the community versus the one in the south was the only risk factor associated with Cyclospora infection in multivariate analyses (odds ratio, 18.5; 95% confidence interval, 2.4 to 143.1). The water sample from one of the nine wells or water sources tested (one sample per source) in January 2001, shortly before the investigation began, was positive for Cyclospora by UV fluorescence microscopy and PCR. None of the water samples from the 46 wells or water sources tested during the investigation (one sample per source per testing period, including the artesian wells) were positive for Cyclospora. Further studies are needed to assess the role of water as a possible risk factor for Cyclospora infection in Haiti and other developing countries.
-
Isospora belli and Cyclospora cayetanensis
Textbook-Atlas of Intestinal Infections in AIDS, 2003Co-Authors: Mark L. Eberhard, Michael J. ArrowoodAbstract:Intestinal coccidiosis of man is now known to be caused by organisms belonging to the genera Cryptosporidium, Sarcocystis, Isospora, and Cyclospora. Human infection with Isospora has been recognized the longest, whereas Cyclospora is the most recentlyidentified of the four. This chapter will focus on these two genera.
-
A survey for Cyclospora spp. in Kenyan primates, with some notes on its biology.
The Journal of parasitology, 2001Co-Authors: Mark L. Eberhard, Michael N. Njenga, Alex J. Dasilva, Daniel Owino, Eva K. Nace, Kimberly Y. Won, Jason M. MwendaAbstract:From March 1999 through August 2000, 511 stool samples collected from 11 different primate species in 10 geographically distinct locations in Kenya, East Africa, were screened for the presence of Cyclospora spp. oocysts. Positive samples (43/102, 42%) were identified in vervet monkeys (Cercopithecus aethiops) in 4 of 4 locations; 19/206 (9%) in yellow and olive baboons (Papio cynocephalus, P. anubis, respectively) in 5 of 5 locations; and 19/76 (25%) in black and white colobus monkeys (Colobus angolensis, C. guereza, respectively) from 2 of 3 locations. DNA sequences obtained from 18 S rRNA coding regions from respective subsets of these positive samples were typed as Cyclospora cercopitheci (samples from Cercopithecus aethiops). Cyclospora papionis (samples from Papio cynocephalus and P. anubis), and Cyclospora colobi (samples from Colobus angolensis and C. guereza). Cyclospora oocysts were not detected in samples collected from patas, highland sykes, lowland sykes, blue sykes, DeBrazza, or red-tailed monkeys. A coded map showing the geographic location of the collected samples is given. Stool samples from 1 troop of vervet monkeys were collected over a 12-mo period. Positive samples ranged between 21 and 63%. These results suggest that there is no strongly marked seasonality evident in Cyclospora infection in monkeys as has been noted in human infection. This is further confirmed by the recovery of positive samples collected from vervet monkeys, baboons, and colobus monkeys at all times of the year during this survey. This absence of seasonality in infection is especially notable because of the extreme weather patterns typical of Kenya, where marked rainy and dry seasons occur. A second noteworthy observation is that the striking host specificity of the Cyclospora species initially described was confirmed in this survey. Baboons were only infected with C. papionis, vervet monkeys with C. cercopitheci, and colobus monkeys with C. colobi, despite geographic overlaps of both the monkey and parasite species and wide geographic distribution of each parasite and monkey host.
Charles R. Sterling - One of the best experts on this subject based on the ideXlab platform.
-
Synopses Cyclospora: An Enigma Worth Unraveling
2013Co-Authors: Charles R. Sterling, Ynés R. OrtegaAbstract:In part, Cyclospora cayetanensis owes its recognition as an emerging pathogen to the increased use of staining methods for detecting enteric parasites such as Cryptosporidium. First reported in patients in New Guinea in 1977 but thought to be a coccidian parasite of the genus Isospora, C. cayetanensis received little attention until it was again described in 1985 in New York and Peru. In the early 1990s, human infection associated with waterborne transmission of C. cayetanensis was suspected; foodborne transmission was likewise suggested in early studies. The parasite was associated with several disease outbreaks in the United States during 1996 and 1997. This article reviews current knowledge about C. cayetanensis (including its association with waterborne and foodborne transmission), unresolved issues, and research needs. Cyclospora Overview Cyclospora cayetanensis is a protozoan parasite (subphylum Apicomplexa, subclass Coccidiasina, order Eucoccidiorida, family Eimeriidae). The organism’s link to the Eimeriida
-
Detection of Cyclospora cayetanensis in wastewater
Applied and environmental microbiology, 1998Co-Authors: Gregory D. Sturbaum, Charles R. Sterling, Ynés R. Ortega, Robert H Gilman, Lilia Cabrera, Donald A. KleinAbstract:Cyclospora cayetanensis causes diarrheal disease worldwide without a confirmed mode of transmission. Wastewater was examined for the presence of this organism. Oocysts were detected microscopically, and their identity was confirmed by molecular techniques. These findings verify that current techniques can isolate Cyclospora oocysts and suggest that fecally contaminated water may act as a vehicle of transmission.
-
Isolation of Cryptosporidium parvum and Cyclospora cayetanensis from vegetables collected in markets of an endemic region in Peru.
The American journal of tropical medicine and hygiene, 1997Co-Authors: Ynés R. Ortega, Robert H Gilman, Concepcion Roxas, Norma J. Miller, Lilia Cabrera, Carmen Taquiri, Charles R. SterlingAbstract:Cryptosporidium parvum and Cyclospora cayetanensis are protozoan pathogens that cause prolonged diarrhea in both immunocompetent and immunocompromised hosts. Cryptosporidium parvum can be transmitted via the fecal-oral route, while the exact mechanisms of transmission of Cyclospora cayetanensis have not been fully determined. Humans appear to be the sole host for the latter and a distinct seasonality has been observed in endemic areas around the world. Samples of vegetables were collected at several small markets in a periurban slum in Peru during the seasons of high and low incidence. The vegetables were washed, the supernatants were collected and centrifuged, and the pellets were resuspended in a solution of 2.5% potassium dichromate. Pellets were examined using direct microscopic observation, acid-fast staining, and immunofluorescent assays for C. parvum and Cyclospora cayetanensis oocysts. Samples were collected during three time periods: the season of low incidence, the beginning of the season of high incidence, and end of the season of high incidence. Of the total vegetables examined, 14.5% contained C. parvum oocysts and 1.8% had Cyclospora oocysts. Thus, market vegetables may provide a route by which Cryptosporidium and Cyclospora can be transmitted. Our study also suggests that washing vegetables does not completely remove Cryptosporidium and Cyclospora oocysts.
-
pathologic and clinical findings in patients with cyclosporiasis and a description of intracellular parasite life cycle stages
The Journal of Infectious Diseases, 1997Co-Authors: Ynés R. Ortega, Robert H Gilman, Concepcion Roxas, Raymond B Nagle, J Watanabe, Juan Miyagui, Hugo Quispe, Patricia Kanagusuku, Charles R. SterlingAbstract:Cyclospora cayetanensis has been observed in the feces of persons with prolonged diarrhea. A description of the symptoms and histopathologic findings for patients with cyclosporiasis is presented. The intracellular life-cycle stages of these parasites in the enterocytes of patients will also be described. Seventeen Peruvian patients positive for Cyclospora organisms were surveyed and underwent endoscopy, and their symptoms were recorded. Patients presented with gastrointestinal symptoms, including diarrhea, flatulence, weight loss, abdominal discomfort, and nausea. Jejunal biopsies showed an altered mucosal architecture with shortening and widening of the intestinal villi due to diffuse edema and infiltration by a mixed inflammatory cell infiltrate. There was reactive hyperemia with vascular dilatation and congestion of villous capillaries. Parasitophorous vacuoles contained sexual and asexual forms. Type I and II meronts, with 8-12 and 4 fully differentiated merozoites, respectively, were found at the luminal end of epithelial cells. These findings demonstrate the complete developmental cycle associated with host changes due to Cyclospora organisms.
-
a new coccidian parasite apicomplexa eimeriidae from humans
Journal of Parasitology, 1994Co-Authors: Robert H Gilman, Ynés R. Ortega, Charles R. SterlingAbstract:A new coccidian parasite has been found in stool specimens of humans with and without diarrhea. The oocyst of this parasite measures 8.6 microns in diameter (7.7-9.9 microns), with ovoid sporocysts 4.0 x 6.3 (3.3-4.4 x 5.5-7.1) microns. Each oocyst has 2 sporocysts and each sporocyst contains 2 sporozoites. Based on these characteristics and the structures observed by electron microscopy, this parasite has been classified in the genus Cyclospora. We propose the name Cyclospora cayetanensis n. sp. for this new human parasite.
Corinne S. L. Ong - One of the best experts on this subject based on the ideXlab platform.
-
Cyclospora spp in herbs and water samples collected from markets and farms in hanoi vietnam
Tropical Medicine & International Health, 2008Co-Authors: Nguyen Thuy Tram, Linda Hoang, Phung Dac Cam, Murray W. Fyfe, Phan Thu Chung, Judith L Isaacrenton, Corinne S. L. OngAbstract:Summary Objective To determine the prevalence of Cyclospora spp. oocysts in herb and water samples as well as in fecal specimens of clinical cases of diarrhoea in Hanoi, Vietnam. Method From November 2004 to October 2005, water and herb samples collected from markets and farms in Hanoi were examined for the presence of Cyclospora spp. oocysts in concentrated sediments and washings using UV epifluorescence examination of a wet mount. In addition, hospital based surveillance studies were carried out using a structured questionnaire which focused on potential risk factors for cyclosporiasis. Stool specimens were collected from individuals with diarrhoea attending primary healthcare facilities and examined for Cyclospora spp. oocysts by modified acid fast smear and wet mount examination using both light and UV epifluorescence microscopy. Results Cyclospora spp. were found in 34/288 (11.8%) market water and herb samples, and in 24/287 (8.4%) farm samples. All varieties of herbs sold at the market and grown in farms were contaminated with Cyclospora spp. oocysts. A marked seasonal increase in Cyclospora spp. contamination was observed before the rainy season (39/288) from November to April compared to the rainy season (19/268) from May to October (χ2 = 7.593, P = 0.006). However, Cyclospora spp. was not found in any stool samples collected in hospital-based surveillance studies. Conclusions These results confirm the presence of Cyclospora spp. which varies seasonally in environmental samples (water and herbs collected from farms and markets) within the Hanoi metropolitan area. Objectif: Determiner la prevalence d’oocystes de Cyclospora spp dans des echantillons d’herbes et d’eau ainsi que dans des specimens de matieres fecales de cas cliniques de diarrhee a Hanoi au Vietnam. Methode: De novembre 2004 a Octobre 2005, des echantillons d’eau et d’herbe recueillis sur les marches et fermes a Hanoi ont ete examines pour la presence d’oocystes de Cyclospora spp dans les sediments concentres et les eaux de lavage, en utilisant l’examen UV par epifluorescence d’un montage humide. En outre, des etudes de surveillance hospitaliere ont ete effectuees en utilisant un questionnaire structure ciblant les facteurs de risque potentiels pour la cyclosporose. Des specimens de selles ont ete collectes aupres de personnes souffrant de diarrhee visitant des services de soins de sante primaires et examines pour les oocystes de Cyclospora spp par la methode modifiee de frottis acido resistant et examen de montage humide en utilisant a la fois la microscopie a lumiere et aepifluorescence UV. Resultats: Cyclospora spp a ete retrouve dans 34 des 288 (11,8%) echantillons d’herbes et d’eau du marche et dans 24 des 287 (8,4%) echantillons de fermes. Toutes les varietes d’herbes vendues sur le marche et cultivees dans les fermes etaient contaminees par des oocystes de Cyclospora spp. Une forte augmentation saisonniere de Cyclospora spp. Une augmentation marquee de contamination saisonniere a ete observee avant la saison des pluies (39/288) de novembre a avril par rapport a la saison des pluies (19/268) de mai a octobre (χ2 = 7,593; p = 0,006). Toutefois, Cyclospora spp n’a pas ete retrouve dans les echantillons de selles collectes pour les etudes de surveillance hospitaliere. Conclusions: Ces resultats confirment la presence de Cyclospora spp variant selon les saisons dans des echantillons de l’environnement (eaux et herbes collectees dans les fermes et marches) dans la region metropolitaine de Hanoi. Objetivo: Determinar la prevalencia de oocitos de Cyclospora spp. en hierbas y muestras de agua, al igual que en muestras fecales de casos clinicos de diarrea en Hanoi, Vietnam. Metodo: Entre Noviembre 2004 y Octubre 2005, se recolectaron muestras de agua y hierbas de mercados y granjas y se examinaron los sedimentos concentrados y lavados mediante epifluorescencia en montaje humedo, en busca de oocitos de Cyclospora spp. Adicionalmente, se llevaron a cabo estudios de seguimiento hospitalario utilizando un cuestionario estructurado con un enfoque en posibles factores de riesgo para ciclosporiasis. Se recolectaron y examinaron en busca de oocitos muestras fecales de individuos con diarrea que se presentaron en centros de atencion primaria. El analisis se realizo mediante baciloscopia modificada y montaje humedo, utilizando tanto microscopia de luz como de epifluorescia. Results: Se encontroCyclospora spp. en 34 de 288 (11.8%) muestras de agua y hierbas tomadas del mercado, y en 24 de 287 (8.4%) muestras de granjas. Todas las variedades de hierbas vendidas en el mercado o cultivadas en las granjas estaban contaminadas con oocitos de Cyclospora spp. Se observo un aumento estacional importante de contaminacion con Cyclospora spp. antes de la estacion lluviosa (39/288) entre Noviembre y Abril, comparado con la estacion lluviosa (19/268) entre Mayo y Octubre (χ2 = 7.593, p = 0.006). Sin embargo, no se halloCyclospora spp. en ninguna de las muestras fecales recogidas en estudios de vigilancia hospitalaria. Conclusiones: Estos resultados confirman la presencia de Cyclospora spp. la cual varia de forma estacional en muestras ambientales (agua y hierbas recolectadas de granjas y mercados) dentro del area metropolitana de Hanoi.
-
Cyclospora spp. in herbs and water samples collected from markets and farms in Hanoi, Vietnam.
Tropical medicine & international health : TM & IH, 2008Co-Authors: Nguyen Thuy Tram, Linda Hoang, Phung Dac Cam, Phan Thi Thu Chung, Murray W. Fyfe, Judith L. Isaac-renton, Corinne S. L. OngAbstract:To determine the prevalence of Cyclospora spp. oocysts in herb and water samples as well as in fecal specimens of clinical cases of diarrhoea in Hanoi, Vietnam. From November 2004 to October 2005, water and herb samples collected from markets and farms in Hanoi were examined for the presence of Cyclospora spp. oocysts in concentrated sediments and washings using UV epifluorescence examination of a wet mount. In addition, hospital based surveillance studies were carried out using a structured questionnaire which focused on potential risk factors for cyclosporiasis. Stool specimens were collected from individuals with diarrhoea attending primary healthcare facilities and examined for Cyclospora spp. oocysts by modified acid fast smear and wet mount examination using both light and UV epifluorescence microscopy. Cyclospora spp. were found in 34/288 (11.8%) market water and herb samples, and in 24/287 (8.4%) farm samples. All varieties of herbs sold at the market and grown in farms were contaminated with Cyclospora spp. oocysts. A marked seasonal increase in Cyclospora spp. contamination was observed before the rainy season (39/288) from November to April compared to the rainy season (19/268) from May to October (chi(2) = 7.593, P = 0.006). However, Cyclospora spp. was not found in any stool samples collected in hospital-based surveillance studies. These results confirm the presence of Cyclospora spp. which varies seasonally in environmental samples (water and herbs collected from farms and markets) within the Hanoi metropolitan area.
Jeevan B. Sherchand - One of the best experts on this subject based on the ideXlab platform.
-
Cyclospora Infection among School Children in Kathmandu, Nepal: Prevalence and Associated Risk Factors
Tropical medicine and health, 2015Co-Authors: Dinesh Bhandari, Jatan B Sherchan, Sarmilla Tandukar, Hiramani Parajuli, Pratigya Thapa, Prakash Chaudhary, Dhiraj Shrestha, Pradeep Kumar Shah, Jeevan B. SherchandAbstract:Background: The intestinal coccidian protozoa Cyclospora cayetanensis has emerged as an important cause of parasitic diarrhea among children living in developing countries. This study aimed to determine the prevalence of Cyclospora among the school children of Kathmandu with reference to various associated risk factors. Methodology: A total of five hundred and seven stool samples from students between the age of 3–14 years, studying in 13 different schools in Kathmandu were collected during the study period (May–November, 2014) and processed at the Public Health Research Laboratory, Institute of Medicine, Kathmandu, Nepal. A modified acid fast staining technique (Kinyoun’s method) was used to detect oocyst of Cyclospora from the formal-ether concentrated stool samples. Results: Cyclospora was detected in 3.94% (20/507) of the stool samples examined. The prevalence was found to be highest among the students in the 3–5 year age group i.e. 10.15% (13/128), peaking during the rainy season (June–August). The detection rate was found to be significantly higher (p < 0.05) among children presenting with diarrheal symptoms, household keeping livestock and consumers of raw vegetables/fruits, showing a prevalence of 10.57% (11/104), 10.11% (9/89) and 7.25% (14/193) respectively. Conclusion: Consumption of untreated drinking water, fresh produce (raw fruits/vegetables) without proper washing and the presence of livestock at home were found to be predisposing factors for higher susceptibility of infection due to Cyclospora. This finding confirms the existence of a public-health issue with potentially serious consequences whereby children can be infected through exposure to oocysts in contaminated food and water and get ill as a result.
-
An epidemiological study of Cyclospora cayetanensis in Nepalese people
Journal of Institute of Medicine, 2007Co-Authors: Jeevan B. Sherchand, Jh CrossAbstract:Background: Cyclospora cayetanensis is a coccidian parasite that causes recurrent gastroenteritis among children living under poor sanitary condition and adults from industrialized countries who lived or traveled in endemic developing countries. Materials and Methods: A total of 1842 stool specimens from gastroenteritis patients were examined between March 2005 to February 2006 and collected various types of faecal specimens from human, animals and samples of water and green leafy vegetables. Results: Of 1842 stool specimens collected from different areas of Nepal, 146 (7.9 %) were found to be positive for Cyclospora cayetanensis with the majority were from children 2-9 years of age. The highest rate of infections was found in the month of June; (31.6%). Cyclospora cayetanensis were found to be contaminated in green vegetables including leaves of basil, mint leaves, water sources and feces of domestic animals and these findings were presented in the paper. Conclusion: Cyclospora -like oocysts were isolated for the first time from the leaves of basil, a holy plant of Nepal and the study indicated that vegetarian people were also found highest rate (65.1%) of Cyclosporiasis. However, to obtain more evidence on the source of infection, specimens from rodents, birds, insects and domestic animals are need for an extensive study. Key Words: Cyclospora cayetanensis, oocysts The full text of this paper is available at Journal of Institute of Medicine website
-
Study on Cyclospora Cayetanensis in Kathmandu Valley
Journal of Nepal Medical Association, 2004Co-Authors: Ranjana Gupta, Jeevan B. Sherchand, R Gurung, Sanjeev JhaAbstract:Cyclospora caytanensis, a human pathogenic coccidian parasite owes its recognition as an emerging parasite, which continues to be found throughout the world. Its prevalence was investigated in Kathmandu valley, Nepal in 2003. Stool examination was performed with a total of 500 specimens from 3 Hospitals, 1 Geriatric Centre (Briddhaashram), 1 Infectious and Tropical Disease Research Center/Nepal and 8 Slum areas by direct smear technique. Out of these specimens, Cyclospora caytenensis oocysts were found in 7% of specimens with the age range from 2 months to 67 years. To identify possible sources for Cyclospora infection, water samples from 3 rivers, 134 fecael samples of animals and 43 samples of green leafy vegetables wash were collected and examined by formal-ether sedimentation and floatation technique. As a result, oocyst of Cyclospora was identified only in chicken stool sample, which could be possible reservoir host for Cyclospora infection. However, further studies are needed to shed light on possible sources of infection.Key Words: Cyclospora caytanensis, coccidian parasite, diarrhoea, faecal specimens.
-
PARASITIC EPIDEMIOLOGICAL STUDIES OF Cyclospora CAYETANENSIS IN NEPAL
Southeast Asian Journal of Tropical Medicine and Public Health, 2004Co-Authors: Jeevan B. SherchandAbstract:Prior to 1995, the coccidian parasite Cyclospora cayetanensis was reported as a cause of gastroenteritis among children living in poor sanitary conditions and adults from industrialized countries who lived or traveled in developing countries. In 1999 and 2001, Cyclospora infection in Nepal was linked to the consumption of undercooked, contaminated green leafy vegetables and exposure to contaminated water. Some domestic animals were also found passing Cyclospora-like oocysts. To extend our understanding of the parasitosis, we conducted a surveillance in health-care facilities and studied vegetable farmers, as well as carrying out a case-control study. This was done to assess risk factors for the disease in Nepal. From September 2, 2002 to August 30, 2003, 137 (6.4%) of 2,138 surveillance specimens tested positive for Cyclospora; prevalence peaked in June with 36/137 (26.3%). Infection was most common in children 2-9 years of age and in adults with gastroenteritis. Among 176 vegetable farmers and family members monitored from June 25 to August 30, 18 had Cyclospora infection. In the case-control analysis, 61 (95.3%) of 64 persons with Cyclospora infection reported drinking unsafe water within 12 days before illness, compared with 64 (74.4%) of 86 controls [Odds ratio (OR) 7.0, at 95% confidence intervals (CI)]. Other risk factors included water sources, type of sewage drainage, domestic animals or chickens in the household, and contact with soil. In addition, we observed a pattern of clinical and epidemiological finding associated with the detection of cyclosporiasis.
-
Study of Cyclospora cayetanensis in health care facilities, sewage water and green leafy vegetables in Nepal.
Southeast Asian Journal of Tropical Medicine and Public Health, 1999Co-Authors: Jeevan B. Sherchand, John H. Cross, Mathura P. ShresthaAbstract:Cyclospora cayetanensis, a newly emerging parasite, is endemic in Nepal. A total of 2,123 stool specimens were collected from 3 health care facilities based on clinical symptoms during the period between 1995 to October, 1998. Out of these specimens, cayetanensis oocysts were found in 632 (29.8%). To identify possible sources for Cyclospora infection, drinking water, sewage water, green-leafy vegetables including fecal samples of various animals were collected and examined. The vegetable leaves were washed in distilled water then the washings, sewage water and drinking water were centrifuged and the sediment were examined microscopically. As a result, oocyst of Cyclospora were identified in sewage water and vegetable washings on four different occasions in June, August, October and November. The positive results were also confirmed as C. cayetanensis by development of 2 sporocysts after 2 week incubation period in potassium dichromate. A survey of 196 domestic animals from the same areas demonstrated that two chickens were positive for Cyclospora-like organism and others were negative. Although further studies are needed to clarify the direct link between Cyclospora infection and these sources, the results suggest that sewage water, green leafy vegetables are possible sources of infection and chickens could be possible reservoir host of Cyclospora in Nepal.
