Immunology and pathology of echinostomes and other intestinal trematodes.

Intestinal trematodes constitute a major group of helminths that parasitize humans and animals with relevant morbidity and mortality. Despite the importance of the intestinal trematodes in medical and veterinary sciences, immunology and pathology of these helminth infections have been neglected for years. Apart from the work focused on the members of the family Echnistomatidae, there are only very isolated and sporadic studies on the representatives of other families of digeneans, which makes a compilation of all these studies necessary. In the present review, the most salient literature on the immunology and pathology of intestinal trematodes in their definitive hosts in examined. Emphasis will be placed on members of the echinostomatidae family, since it is the group in which the most work has been carried out. However, we also review the information on selected species of the families Brachylaimidae, Diplostomidae, Gymnophallidae, and Heterophyidae. For most of these families, coverage is considered under the following headings: (i) Background; (ii) Pathology of the infection; (iii) Immunology of the infection; and (iv) Human infections.

Changes in resident microbiota associated with mice susceptibility or resistance to the intestinal trematode Echinostoma caproni.

Echinostoma caproni (Trematoda: Echinostomatidae) is an intestinal trematode with no tissue phases in the definitive host that has been extensively used as an experimental model to study the factors that determine resistance against intestinal helminths. In E. caproni infections in mice, interleukin-25 (IL-25) plays a critical role and it is required for the resistance to infection. However, little is known on the factors that determine its production. Primary E. caproni infection in mice is characterized by the development of chronic infections and elevated worm recovery, in relation to a local Th1 response with elevated production of interferon-γ. However, partial resistance against secondary E. caproni infections in ICR (Institute of Cancer Research) mice is developed after the chemotherapeutic cure of a primary infection and the innately produced IL-25 after pharmacological treatment. In this paper, we analyse the potential role of intestinal microbiota in the production of IL-25, and the subsequent resistance to infection. For this purpose, we analysed the production of IL-25 under conditions of experimental dysbiosis and also the changes in the resident microbiota in primary infections, pharmacological curation and secondary infections. The results obtained showed that resident microbiota play a major role in the production of IL-25 and the appearance of members of the phylum Verrucomicrobia as a consequence of the curation of the primary infection could be related to the partial resistance to secondary infection.

Ascariasis in a 75-year-old man with small bowel volvulus: a case report.

BACKGROUND: Ascaris lumbricoides and Ascaris suum are the most common soil-transmitted helminths of humans and pigs, respectively. The zoonotic potential of A. suum has been a matter of debate for decades. This study was aimed to present a case of human ascariasis caused by A. suum in southern Italy. CASE PRESENTATION: A 75-year-old man presented to the department of surgery in Avellino (southern Italy) complaining of abdominal pain and vomiting. Physical examination revealed bloating and abdominal tenderness. A computed tomography scan showed air-fluid levels and small bowel distension. During exploratory laparotomy a small bowel volvulus with mesenteritis was evident and surprisingly an intraluminal worm was detected. The worm was removed with a small enterotomy and identified as an adult female of A. suum based on morphological and molecular analysis. Faecal examination revealed the presence of unfertilized Ascaris eggs with an intensity of 16 eggs per gram (EPG) of faeces. The patient was treated with mebendanzole 100 mg twice a day for 3 days. The post-operative course was regular with re-alimentation after 3 days and discharge after 12 days. CONCLUSIONS: This report shows as A. suum can function as a relevant agent of human zoonosis. Therefore, in patients with bowel obstruction with no evident aetiology a helminthic infestation should be considered for an accurate diagnosis, especially in patients living in rural areas.

Epidemiology and spatial distribution of Echinococcus granulosus in sheep and goats slaughtered in a hyperendemic European Mediterranean area.

BACKGROUND: Cystic echinococcosis (CE) is a worldwide parasitic zoonosis caused by the larval stage of Echinococcus granulosus sensu lato affecting livestock, particularly sheep and goats. However, often this parasitosis is underestimated. For this reason, this study aimed to evaluate the epidemiological features and spatial distribution of CE in sheep and goats slaughtered in a hyperendemic Mediterranean area. METHODS: A survey was conducted in the Basilicata region (southern Italy) from 2014 to 2019. A total of 1454 animals (1265 sheep and 189 goats) from 824 farms were examined for hydatid cyst detection by visual inspection, palpation and incision of target organs. All the CE cysts were counted and classified into five morphostructural types (unilocular, multiseptate, calcified, caseous and hyperlaminated). Molecular analysis was performed on 353 cysts. For spatial analysis, a kriging interpolation method was used to create risk maps, while clustering was assessed by Moran's I test. RESULTS: CE prevalence of 72.2% (595/824) and 58.4% (849/1454) was observed at the farm and animal levels, respectively, with higher values in sheep (62.9%) than goats (28.0%). The liver and lungs were the most frequently infected organs in both sheep and goats. Most of recovered cysts were of the calcified and multiseptate morphotypes. All the isolates were identified as E. granulosus sensu stricto (genotypes G1-G3). Spatial distribution showed a moderate clustering of positive animals. CONCLUSION: The findings of this study can be used to better understand the eco-epidemiology of echinococcosis and to improve CE surveillance and prevention programs in regions highly endemic for CE.

Intestinal parasites in child and youth populations of Argentina: Environmental factors determining geographic distribution.

The transmission of intestinal parasites is generally considered to be "mediated by the environment" which suggests that they are particularly sensitive to the changes that occur in it. The aim of the present study was to evaluate the environmental variables that act as risk factors for intestinal parasitosis in children and youths in Argentina. The association between environmental variables related to temperature, precipitation and soil and parasitosis found in children and youths from different provinces was evaluated, including land use/cover classes obtained from satellite images. Of the total population analyzed, 66.9% of the participants were parasitized. The total number of identified parasite species was 17 and the most prevalent were Blastocystis sp. (42.2%), Enterobius vermicularis (33.6%) and Giardia lamblia (17.0%). Infection by protozoa, and by G. lamblia in particular, was greater when the mean summer temperature was higher (OR=1.2 for both). Blastocystis sp. and geohelminths were greater due to an increase in isothermality (OR=1.1 and 1.2, respectively). The risk of infection with Ascaris lumbricoides was associated with an increase in the temperature in the wettest quarter (OR=1.2). Hookworm infection was associated with an increase in the normalized difference vegetation index (OR=32.5). Most of participants infected with hookworms lived in areas with abundant arboreal-shrubby and agropastoral use vegetation. The heterogeneous distribution of enteric parasites is indicative of the wide environmental variability of Argentina.

Intestinal parasites in canine feces contaminating urban and recreational areas in Ushuaia (Argentina).

Wild and domestic dogs are important reservoir hosts of numerous intestinal parasites that represent potential infection sources for both humans and wild or other domestic animals. The aim of this study was to determine the presence, diversity, and contamination potential of intestinal parasites in dog feces contaminating urban and recreational areas in Ushuaia (Tierra del Fuego province, Argentina). A total of 80 canine fecal samples were collected from urban (playgrounds, streets, sidewalks, squares and coastal walks) and recreational areas (winter centers for raising and training sled dogs) in 2018. Samples were preserved in 5% formalin and processed using formalin-ethyl acetate sedimentation and FLOTAC dual Pellet techniques. Data were analyzed using the R software. At least one parasite species was recovered in 32.5% of the total samples examined. Of the seven parasite species detected, infection by protozoan species was higher than helminth infections (28.8% versus 8.8%). Sarcocystis sp. (20.0%), Giardia sp. (8.8%) and Cystoisospora spp. (7.5%) were the most frequent species, followed by Toxocara canis (5.0%), Echinococcus spp./Taenia spp. (2.5%), Trichuris vulpis and Uncinaria sp. (1.3% for both). Single infections (69.2%) were more frequent than coinfections with two (19.2%) and three parasite species (11.5%). This study provides the first description of the diversity and frequency of intestinal parasite species in dog feces from Ushuaia, the southernmost city in the world. The unfavorable environment of Ushuaia, characterized by low temperatures and winter snowfall, is likely to reduce parasite survivability, decreasing contamination potential. Some parasite species found are potentially zoonotic and represent an important risk for the human population and a source of infection to free-roaming pets. The results of this study revealed the need to strengthen the prevention, surveillance and control of these infections in pets, as well as to implement programs for public health education, control measures for the free-roaming canine population, and responsible pet ownership in the study area.

Parásitos intestinales en poblaciones infantojuveniles; ambiente y comportamiento social / Prevalence of intestinal parasites in child and youth populations; environment and social behavior

Introduction: The decreasing prevalence of parasitosis from north to south in Argentina has led the scientific community to focus the epidemiological studies on the most vulnerable areas and, consequently, neglect the populations of Patagonia (South Argentina). The objectives of the present study were (i) to determine the prevalence of intestinal parasites in children and youth of Puerto Madryn (Chubut province, Patagonia), and (ii) to evaluate the parasitic infections found concerning socio-environmental factors and hygiene practices of the population. Materials and methods: Serial stool samples were processed using modified Ritchie and FLOTAC dual pellet techniques, and samples of anal swabs were examined by sedimentation. Socio-environmental variables and hygiene practices of the participants were surveyed using a semi-structured questionnaire. Results: Of all examined participants, 39.1% (68/174) were parasitized. A total of 6 parasite species were found and the most prevalent were Blastocystis sp (19.0%), Enterobius vermicularis (17.8%), and Giardia lamblia (6.3%). The risk of parasitosis and infection for Blastocystis sp was greater in participants who lived in houses without piped water (OR = 2.9 and OR = 3.2, respectively). The risk of infection for G. lamblia was positively associated with the lack of public waste collection service (OR = 5.6). Infection for E. vermicularis was higher in participants whose parents had a basic level of education (OR = 5.0). Conclusion: The parasitic infections observed reflect the environmental conditions of Patagonia and the need to focus studies on populations from peripheral areas to urban centers that are exposed to greater socio-economic vulnerability.

Introducción: La prevalencia de parasitosis decreciente de norte a sur en la Argentina, ha llevado a la comunidad científica a enfocar sus estudios epidemiológicos hacia las zonas más vulnerables y desatender a las poblaciones de la Patagonia (sur de Argentina). Los objetivos del presente estudio fueron: determinar la prevalencia de parásitos intestinales en niños y jóvenes de Puerto Madryn (Chubut, Patagonia), y evaluar las infecciones parasitarias en relación con los factores socioambientales y las prácticas de higiene de la población. Materiales y métodos: Se procesaron muestras seriadas de materia fecal mediante las técnicas Ritchie modificada y FLOTAC dual pellet, y muestras de escobillado anal por sedimentación. Se relevaron las variables socioambientales y las prácticas de higiene de los participantes mediante cuestionarios semiestructurados. Resultados: El 39.1% (68/174) de la población analizada estuvo parasitado. Se halló un total de 6 especies parásitas, las más prevalentes de las cuales fueron Blastocystis sp (19.0%), Enterobius vermicularis (17.8%) y Giardia lamblia (6.3%). El riesgo de parasitosis y de infección por Blastocystis sp fue mayor en los participantes que no poseían agua de red (odds ratio [OR] = 2.9 y OR = 3.2, respectivamente). La infección por G. lamblia se asoció de manera positiva con la falta de recolección pública de residuos (OR = 5.6). La infección por E. vermicularis fue superior en los participantes con padres que tenían un nivel de estudios primario (OR = 5.0). Conclusión: Las infecciones parasitarias observadas reflejan las condiciones ambientales de la Patagonia y la necesidad de orientar los estudios a poblaciones periféricas de los centros urbanos, las cuales están expuestas a mayor vulnerabilidad socioeconómica

Morphological and molecular characterization of Bertiella sp. (Cestoda, Anoplocephalidae) infection in a human and howler monkeys in Argentina.

Bertiella sp. is a typical parasite in non-human primates and only a few cases of bertiellosis have been reported in humans. We present a new case study of bertiellosis in a 42-year-old woman caretaker of howler monkeys in a wild rehabilitation center in Argentina. Bertiella sp. infection was also diagnosed in the monkeys. Proglottids and feces were collected from the caretaker and monkeys; the samples were submitted for parasitological examination by morphological characterization and molecular identification using both nuclear (18S and ITS1-5.8-ITS2 rDNA) and mitochondrial (cox1) markers. Morphological and molecular data were consistent and allowed the classification of the specimen to the genus level. The analyses also showed the presence of cysts of Giardia lamblia and oocysts of Cryptosporidium spp. in howler monkeys, and cysts of Blastocystis sp. in both the caretaker and monkeys. This study recorded the fourth case of bertiellosis in a human host from Argentina and the eighth case in South America. Moreover, this is the first study that compares the morphological and molecular features of Bertiella sp. found in both a human and monkeys from the same geographical region. These results suggest that the cohabitation between humans and monkeys increases the opportunities of infection by Bertiella sp. and other potential zoonotic parasites.

Risk factors for intestinal parasitoses among children and youth of Buenos Aires, Argentina.

INTRODUCTION: Intestinal parasitoses affect millions of people worldwide, especially children of developing countries. In Argentina, the prevalence of these infections varies among areas according to socio-economic and climatic variability. This study aimed to evaluate the prevalence of intestinal parasitoses and risk factors in child and youth populations from neighbourhoods of La Plata (Buenos Aires province, Argentina) affected by occasional floods, including a serious flood in 2013. METHODS: Serial stool samples and anal swabs of 398 individuals were processed using techniques of sedimentation and flotation. Socio-economic variables were surveyed using a semi-structured questionnaire and the land use/cover was determined by classification of a satellite image. RESULTS: Of all examined individuals, 70.9% were parasitized by at least one of the 12 parasites identified. The most prevalent species were Blastocystis sp. (42.7%), Enterobius vermicularis (34.7%) and Giardia lamblia (17.6%). Infection risk factors included houses built with makeshift materials and dirt floors; lack of piped water and public waste collection service, bed-sharing and living in the non-urban area. >70.3% of the participants that lived within <200 m from watercourses or permanent water bodies were parasitized. CONCLUSION: This research shows that parasitic infections are still a serious public health problem and that they are strongly associated with socio-economic conditions and land use/cover. In this context, studies focused on One Health strategy are need to ensure the diagnosis and surveillance of parasitosis and to tackle zoonotic diseases as well as to encourage the development of sanitary and educational programs sustainable over time.

Occurrence of intestinal parasites in Mayan children from Yucatán, Mexico.

Parasitic intestinal infections occur worldwide and affect the poorest and deprived populations. In Mexico, indigenous peoples live with the highest levels of poverty and marginalization. This study aimed to analyze the occurrence of intestinal parasites among Mayan children from the villages of Xkalakdzonot and Paraíso in Yucatán State. Stool samples from 83 children were examined using two coproparasitological tests (formalin-ethyl acetate concentration and FLOTAC Pellet techniques). The overall prevalence of intestinal parasites in children was 65.1%. Six protozoa and four helminths were identified. Blastocystis sp. (44.6%), Giardia intestinalis (26.5%), and Entamoeba coli (26.5%) were the most prevalent parasites. The prevalence of helminth infections (7.1%) was lower in children from Xkalakdzonot than in Paraíso (29.3%). The study provides relevant information on the occurrence of intestinal parasites in Mayan children from two villages. This data, therefore, can be used by local health authorities to plan appropriate programs for parasite control, considering suitable drug therapies and health education.

Intestinal parasitosis, undernutrition and socio-environmental factors in schoolchildren from Clorinda Formosa, Argentina / Parasitosis intestinal, desnutrición y factores socio-ambientales en niños escolares de Clorinda Formosa, Argentina

ABSTRACT Objective To evaluate intestinal parasitosis, undernutrition and socio-environmental factors in schoolchildren from Clorinda (Formosa, Argentina). Materials and Methods Serial fecal samples and anal swabs of 114 schoolchildren, canine feces and soil samples were analyzed. Body weight and height of 215 schoolchildren were measured and undernutrition was estimated according to the World Health Organization criteria. Socio-environmental variables were assessed by means of a semi-structured questionnaire. Results 78.1% of children were infected by at least one of the 12 species identified and 70.8% had multiple parasitic infections. Blastocystis sp., Giardia lamblia and Enterobius vermicularis were the most prevalent. Additionally, 17.5% of children were infected by at least one geohelminth (e.g. Ascarislumbricoides, Trichuris trichiura, hookworms). 64.3% of canine of canine feces were positive and six parasitic species were found; the most frequent were Ancylostoma caninum, Uncinaria stenocephala and G. lamblia. Furthermore, 37.5% of soil samples showed zoonotic parasites (i.e. Ascaris sp., Toxocara sp.). Finally, 10.0% of the children were undernourished and 85.7% of them had parasites. The risk for parasitosis was higher in children that lived in houses with inadequate solid waste disposal and whose parents were unemployed or had temporary jobs. Conclusions The lack of environmental sanitation, unstable employment of parents and the presence of zoonotic species were the most relevant factors observed. Consequently, these conditions result in an increase of parasitic infections and negatively influence the growth of children.(AU)

RESUMEN Objetivo Evaluar la parasitosis intestinal, la desnutrición y los factores socio-ambientales en escolares de Clorinda (Formosa, Argentina). Materiales y Métodos Se analizaron muestras fecales y escobillados anales seriados de 114 escolares, heces caninas y muestras de suelo. Se midió el peso corporal y la talla de 215 escolares y se evaluó la desnutrición según los criterios de la Organización Mundial de la Salud. Las variables socio-ambientales se evaluaron mediante una encuesta semiestructurada. Resultados El 78,1% de los niños estuvieron parasitados por al menos 1 de las 12 especies identificadas y el 70,8% presentó parasitosis múltiples. Blastocystis sp., Giardia lamblia y Enterobius vermicularis fueron las más prevalentes. Además, el 17,5% de los niños estaban infectados con al menos un geohelminto (e.g. Ascaris lumbricoides, Trichuris trichiura, ancylostomideos). El 64,3% de las heces caninas resultaron positivas y se encontraron seis especies parasitarias; las más frecuentes fueron Ancylostoma caninum, Uncinaria stenocephala y G. lamblia. Además, el 37,5% de las muestras de suelo mostraron parásitos zoonóticos (i.e. Ascaris sp., Toxocara sp.). Finalmente, el 10% de los niños estaban desnutridos y el 85,7% de ellos resultaron parasitados. El riesgo de parasitosis fue mayor en los niños que vivían en casas con eliminación inadecuada de desechos sólidos y cuyos padres estaban desempleados o tenían empleos temporales. Conclusiones La falta de saneamiento ambiental, el empleo inestable de los padres y la presencia de especies zoo-nóticas fueron los factores observados más relevantes. En consecuencia, estas condiciones resultan en un aumento de las infecciones parasitarias e influyen negativamente en el crecimiento de los niños.(AU)

Intestinal parasitosis, undernutrition and socio-environmental factors in schoolchildren from Clorinda Formosa, Argentina.

OBJECTIVE: To evaluate intestinal parasitosis, undernutrition and socio-environmental factors in schoolchildren from Clorinda (Formosa, Argentina). MATERIALS AND METHODS: Serial fecal samples and anal swabs of 114 schoolchildren, canine feces and soil samples were analyzed. Body weight and height of 215 schoolchildren were measured and undernutrition was estimated according to the World Health Organization criteria. Socio-environmental variables were assessed by means of a semi-structured questionnaire. RESULTS: 78.1% of children were infected by at least one of the 12 species identified and 70.8% had multiple parasitic infections. Blastocystis sp., Giardia lamblia and Enterobius vermicularis were the most prevalent. Additionally, 17.5% of children were infected by at least one geohelminth (e.g. Ascarislumbricoides, Trichuris trichiura, hookworms). 64.3% of canine of canine feces were positive and six parasitic species were found; the most frequent were Ancylostoma caninum, Uncinaria stenocephala and G. lamblia. Furthermore, 37.5% of soil samples showed zoonotic parasites (i.e. Ascaris sp., Toxocara sp.). Finally, 10.0% of the children were undernourished and 85.7% of them had parasites. The risk for parasitosis was higher in children that lived in houses with inadequate solid waste disposal and whose parents were unemployed or had temporary jobs. CONCLUSIONS: The lack of environmental sanitation, unstable employment of parents and the presence of zoonotic species were the most relevant factors observed. Consequently, these conditions result in an increase of parasitic infections and negatively influence the growth of children.

Formalin-ethyl acetate concentration, FLOTAC Pellet and anal swab techniques for the diagnosis of intestinal parasites.

The aim of this study was to compare formalin-ethyl acetate concentration and FLOTAC Pellet techniques for the diagnosis of intestinal parasites in human stool samples. The anal swab method was used for the specific detection of Enterobius vermicularis. The study was performed in children and youth from Puerto Madryn (South Argentina). A total of 174 individuals were examined using the formalin-ethyl acetate concentration technique (FECT), the FLOTAC Pellet technique with saturated sodium chloride and zinc sulphate flotation solutions and anal swabs. The performance of copromicroscopic techniques was evaluated according to sensitivity, negative predictive value and Kappa index. Overall, 39.1% of the individuals were parasitised. The most prevalent species was Blastocystis sp. (19%) followed by E. vermicularis (17.8%), Giardia lamblia (6.3%), Entamoeba coli (5.7%), Hymenolepis nana and Endolimax nana (1.1%). The FECT was the most sensitive technique for Blastocystis sp., G. lamblia and E. coli infections, whereas FLOTAC Pellet techniques were the most sensitive for H. nana diagnosis. Anal swabs detected the highest percentage of E. vermicularis infection. This was the first time that the FLOTAC Pellet technique was used to detect intestinal parasites in humans. The FECT continues to be a reliable method for detecting protozoa and the FLOTAC Pellet technique gains importance in the diagnosis of helminths. Anal swab test remains the method of choice for the detection of E. vermicularis. However, when comparing techniques, key factors as preservation methods, preservation times and flotation solutions should be taken into account.

[Cross-sectional study of intestinal parasitosis in child populations in Argentina]. / Estudio transversal de las parasitosis intestinales en poblaciones infantiles de Argentina.

OBJECTIVE: Determine the distribution of intestinal parasitosis in children in nine provinces representative of Argentina's mosaic of contrasting environments. METHODS: Descriptive, observational, cross-sectional study of preschool children (5 years old or under) and school-age children (6-14 years) in the provinces of Buenos Aires (sample taken between 2005 and 2013), Chubut (2010-2013), Corrientes (2012), Entre Ríos (2010-2012), Formosa (2014), La Pampa (2006), Mendoza (2008-2011), Misiones (2005-2008 and 2013), and Salta (2012-2013). Serial samples, fecal samples, and anal swabs were processed using concentration techniques. The results were analyzed by sex, age interval, and province. Frequency of parasitosis (monoparasitosis and multiple parasitoses), wealth of species, and Sørensen similarity coefficient were calculated. RESULTS: Misiones presented the highest frequency of parasitized children and Chubut the lowest (82.0% vs 38.4%; p < 0.01). The number of species was greatest in Misiones and Buenos Aires and lowest in Chubut and La Pampa. Men were parasitized more than women only in Buenos Aires. The highest frequencies were found in preschool children in Buenos Aires and schoolchildren in Mendoza and Misiones (p < 0.05). Monoparasitosis was most frequent in Chubut (67.9%) and multiple parasitosis in Formosa (69.2%). The most frequent species in the majority of provinces were Blastocystis sp. and Enterobius vermicularis. Misiones presented the highest frequency of soil-transmitted helminthes (23.3%) and Mendoza the lowest (0.6%); none were found in Chubut, La Pampa, or Salta. Buenos Aires, Formosa, and Misiones presented a similar species composition, as did Chubut and La Pampa. CONCLUSIONS: The frequency of parasitosis in Argentina corresponds to the country's complex mosaic of climatic and socioeconomic variability and shows a declining trend from north to south and from east to west.

Estudio transversal de las parasitosis intestinales en poblaciones infantiles de Argentina / Cross-sectional study of intestinal parasitosis in child populations in Argentina

Objetivo. Determinar la distribución de las enteroparasitosis en niños de nueve provincias representativas del mosaico de ambientes contrastantes de Argentina. Métodos. Estudio descriptivo, observacional y transversal en niños preescolares (de 5 años o menos) y escolares (de 6 a 14 años) de las provincias de Buenos Aires (muestra tomada entre 2005 y 2013), Chubut (2010-2013), Corrientes (2012), Entre Ríos (2010-2012), Formosa (2014), La Pampa (2006), Mendoza (2008-2011), Misiones (2005-2008 y 2013) y Salta (2012-2013). Se procesaron muestras seriadas, fecales y de escobillado anal, mediante técnicas de concentración. Los resultados se analizaron por sexo, intervalo de edad y provincia. Se calcularon la frecuencia de parasitosis (monoparasitosis y parasitosis múltiple), la riqueza de especies y el coeficiente de similitud de Sørensen. Resultados. Misiones presentó la mayor frecuencia de niños parasitados y Chubut la menor (82,0% vs. 38,4%; p ˂ 0,01). El número de especies fue mayor en Misiones y Buenos Aires y menor en Chubut y La Pampa. Los varones estuvieron más parasitados que las mujeres solo en Buenos Aires. Las mayores frecuencias se encontraron en los preescolares de Buenos Aires y los escolares de Mendoza y Misiones (p < 0,05). La monoparasitosis fue más frecuente en Chubut (67,9%) y las parasitosis múltiples en Formosa (69,2%). Las especies más frecuentes en la mayoría de las provincias fueron Blastocystis sp. y Enterobius vermicularis. De los geohelmintos, Misiones presentó la mayor frecuencia (23,3%) y Mendoza la menor (0,6%); no se hallaron en Chubut, La Pampa y Salta. Buenos Aires, Formosa y Misiones presentaron una composición de especies similar, al igual que Chubut y La Pampa. Conclusiones. Las frecuencias de parasitosis en Argentina responden al complejo mosaico de variabilidad climática y socioeconómica del país y revelan una tendencia descendente de norte a sur y de este a oeste.

Objective. Determine the distribution of intestinal parasitosis in children in nine provinces representative of Argentina’s mosaic of contrasting environments. Methods. Descriptive, observational, cross-sectional study of preschool children (5 years old or under) and school-age children (6-14 years) in the provinces of Buenos Aires (sample taken between 2005 and 2013), Chubut (2010-2013), Corrientes (2012), Entre Ríos (2010-2012), Formosa (2014), La Pampa (2006), Mendoza (2008-2011), Misiones (2005-2008 and 2013), and Salta (2012-2013). Serial samples, fecal samples, and anal swabs were processed using concentration techniques. The results were analyzed by sex, age interval, and province. Frequency of parasitosis (monoparasitosis and multiple parasitoses), wealth of species, and Sørensen similarity coefficient were calculated. Results. Misiones presented the highest frequency of parasitized children and Chubut the lowest (82.0% vs 38.4%; p < 0.01). The number of species was greatest in Misiones and Buenos Aires and lowest in Chubut and La Pampa. Men were parasitized more than women only in Buenos Aires. The highest frequencies were found in preschool children in Buenos Aires and schoolchildren in Mendoza and Misiones (p < 0.05). Monoparasitosis was most frequent in Chubut (67.9%) and multiple parasitosis in Formosa (69.2%). The most frequent species in the majority of provinces were Blastocystis sp. and Enterobius vermicularis. Misiones presented the highest frequency of soil-transmitted helminthes (23.3%) and Mendoza the lowest (0.6%); none were found in Chubut, La Pampa, or Salta. Buenos Aires, Formosa, and Misiones presented a similar species composition, as did Chubut and La Pampa. Conclusions. The frequency of parasitosis in Argentina corresponds to the country’s complex mosaic of climatic and socioeconomic variability and shows a declining trend from north to south and from east to west.

Estudio transversal de las parasitosis intestinales en poblaciones infantiles de Argentina / Cross-sectional study of intestinal parasitosis in child populations in Argentina

RESUMEN Objetivo Determinar la distribución de las enteroparasitosis en niños de nueve provincias representativas del mosaico de ambientes contrastantes de Argentina. Métodos Estudio descriptivo, observacional y transversal en niños preescolares (de 5 años o menos) y escolares (de 6 a 14 años) de las provincias de Buenos Aires (muestra tomada entre 2005 y 2013), Chubut (2010-2013), Corrientes (2012), Entre Ríos (2010-2012), Formosa (2014), La Pampa (2006), Mendoza (2008-2011), Misiones (2005-2008 y 2013) y Salta (2012-2013). Se procesaron muestras seriadas, fecales y de escobillado anal, mediante técnicas de concentración. Los resultados se analizaron por sexo, intervalo de edad y provincia. Se calcularon la frecuencia de parasitosis (monoparasitosis y parasitosis múltiple), la riqueza de especies y el coeficiente de similitud de Sørensen. Resultados Misiones presentó la mayor frecuencia de niños parasitados y Chubut la menor (82,0% vs. 38,4%; p ˂ 0,01). El número de especies fue mayor en Misiones y Buenos Aires y menor en Chubut y La Pampa. Los varones estuvieron más parasitados que las mujeres solo en Buenos Aires. Las mayores frecuencias se encontraron en los preescolares de Buenos Aires y los escolares de Mendoza y Misiones (p < 0,05). La monoparasitosis fue más frecuente en Chubut (67,9%) y las parasitosis múltiples en Formosa (69,2%). Las especies más frecuentes en la mayoría de las provincias fueron Blastocystis sp. y Enterobius vermicularis. De los geohelmintos, Misiones presentó la mayor frecuencia (23,3%) y Mendoza la menor (0,6%); no se hallaron en Chubut, La Pampa y Salta. Buenos Aires, Formosa y Misiones presentaron una composición de especies similar, al igual que Chubut y La Pampa. Conclusiones Las frecuencias de parasitosis en Argentina responden al complejo mosaico de variabilidad climática y socioeconómica del país y revelan una tendencia descendente de norte a sur y de este a oeste.

ABSTRACT Objective Determine the distribution of intestinal parasitosis in children in nine provinces representative of Argentina’s mosaic of contrasting environments. Methods Descriptive, observational, cross-sectional study of preschool children (5 years old or under) and school-age children (6-14 years) in the provinces of Buenos Aires (sample taken between 2005 and 2013), Chubut (2010-2013), Corrientes (2012), Entre Ríos (2010-2012), Formosa (2014), La Pampa (2006), Mendoza (2008-2011), Misiones (2005-2008 and 2013), and Salta (2012-2013). Serial samples, fecal samples, and anal swabs were processed using concentration techniques. The results were analyzed by sex, age interval, and province. Frequency of parasitosis (monoparasitosis and multiple parasitoses), wealth of species, and Sørensen similarity coefficient were calculated. Results Misiones presented the highest frequency of parasitized children and Chubut the lowest (82.0% vs 38.4%; p < 0.01). The number of species was greatest in Misiones and Buenos Aires and lowest in Chubut and La Pampa. Men were parasitized more than women only in Buenos Aires. The highest frequencies were found in preschool children in Buenos Aires and schoolchildren in Mendoza and Misiones (p < 0.05). Monoparasitosis was most frequent in Chubut (67.9%) and multiple parasitosis in Formosa (69.2%). The most frequent species in the majority of provinces were Blastocystis sp. and Enterobius vermicularis. Misiones presented the highest frequency of soil-transmitted helminthes (23.3%) and Mendoza the lowest (0.6%); none were found in Chubut, La Pampa, or Salta. Buenos Aires, Formosa, and Misiones presented a similar species composition, as did Chubut and La Pampa. Conclusions The frequency of parasitosis in Argentina corresponds to the country’s complex mosaic of climatic and socioeconomic variability and shows a declining trend from north to south and from east to west.