Hongos queratinofílicos en suelos de parques de la ciudad de Corrientes, Argentina / Keratinophilic fungi in soils of parks of Corrientes city, Argentina

Antecedentes. El suelo es el reservorio natural de hongos queratinofílicos que constituyen un pequeño pero importante grupo de hongos filamentosos; algunos de ellos se desarrollan típicamente sobre tejidos queratinizados de animales vivos. Hay numerosas especies de geohongos saprobios con habilidades queratolíticas reconocidas y son varios los trabajos realizados con el fin de vincular su presencia a la posible enfermedad humana. Objetivos. Conocer la biota de geohongos en general y la de aquellos queratolíticos en particular en suelos de dos parques públicos. Métodos. Las muestras se tomaron de suelos de dos parques públicos de la ciudad de Corrientes, Argentina, durante dos estaciones del año. Para el aislamiento de los hongos se usaron las técnicas del anzuelo queratínico y la de las diluciones. Resultados. Mediante la técnica del anzuelo se aislaron 170 cepas que se clasificaron en 17 géneros y 21 especies, entre las que merece destacar la presencia de Microsporum canis. El índice de Shannon de hongos queratolíticos fue medio, siendo en otoño (2,27) más alto que en primavera (1,92). Con la técnica de diluciones seriadas se obtuvieron 278 cepas que se clasificaron en 33 géneros y 71 especies; el índice de Shannon fue más alto en otoño (3,9) que en primavera (3,5). Conclusiones. Los suelos estudiados presentan condiciones particularmente favorables para la supervivencia de geohongos patógenos y oportunistas para el hombre y los animales (AU)

Background. The soil is a natural reservoir of keratinophilic fungi, which are a small but important group of filamentous fungi, some of which typically develop on keratinized tissues of living animals. There are numerous species of saprophytic fungi with recognized keratinophilic abilities, and several studies have been undertaken in order to link their presence to possible human disease. Aims. To know the biota of geophilic fungi in general and of keratinophilic fungi particularly in soils from two public parks. Methods. Soil samples from two public parks of Corrientes city, Argentina, were studied during two seasons, using the hook technique and serial dilutions for fungal isolation. Results. Using the hook technique, 170 isolates were classified into 17 genera and 21 species, among which it is worth mentioning the presence of Microsporum canis. Shannon index for keratinophilic fungi in autumn was 2.27, and 1.92 in spring. By means of the serial dilutions technique, 278 fungi isolated were identified into 33 genera and 71 species. Shannon index in autumn was 3.9, and 3.5 in spring. Conclusions. The soils studied have particularly favorable conditions for the survival of pathogens and opportunistic geophilic fungi for humans and animals (AU)

[Keratinophilic fungi in soils of parks of Corrientes city, Argentina]. / Hongos queratinofílicos en suelos de parques de la ciudad de Corrientes, Argentina.

BACKGROUND: The soil is a natural reservoir of keratinophilic fungi, which are a small but important group of filamentous fungi, some of which typically develop on keratinized tissues of living animals. There are numerous species of saprophytic fungi with recognized keratinophilic abilities, and several studies have been undertaken in order to link their presence to possible human disease. AIMS: To know the biota of geophilic fungi in general and of keratinophilic fungi particularly in soils from two public parks. METHODS: Soil samples from two public parks of Corrientes city, Argentina, were studied during two seasons, using the hook technique and serial dilutions for fungal isolation. RESULTS: Using the hook technique, 170 isolates were classified into 17 genera and 21 species, among which it is worth mentioning the presence of Microsporum canis. Shannon index for keratinophilic fungi in autumn was 2.27, and 1.92 in spring. By means of the serial dilutions technique, 278 fungi isolated were identified into 33 genera and 71 species. Shannon index in autumn was 3.9, and 3.5 in spring. CONCLUSIONS: The soils studied have particularly favorable conditions for the survival of pathogens and opportunistic geophilic fungi for humans and animals.

Huevos de Toxocara canis como anzuelo para hongos geófilos en una ciudad subtropical / Toxocara canis eggs as bait for soil fungus in a subtropical city

Antecedentes. Las diferentes técnicas de aislamiento permiten recuperar hongos en función de su capacidad para utilizar o no un determinado sustrato. La técnica de espolvoreado es un método para la recuperación de hongos nematófagos del suelo. Estos hongos son predadores naturales de los nematodos y están ampliamente distribuidos en la naturaleza. Objetivos. Detectar hongos con posible capacidad nematófaga en suelos de parques de la ciudad de Corrientes (Argentina). Métodos. Las muestras de tierra fueron tomadas eligiendo al azar una zona del suelo entre dos árboles, desechando la hojarasca y a no más de 2 cm de profundidad. El aislamiento se realizó según la técnica de espolvoreado utilizando huevos de Toxocara canis como anzuelo. Resultados. Se recogieron 18 muestras de suelo, de las que se aislaron 6 géneros y 8 especies de hongos. El método del espolvoreado, simple y eficiente, tiene la ventaja de utilizar una pequeña cantidad de suelo sin tratamiento y permite aislar hongos que pueden crecer sobre huevos de geohelmintos. Este estudio permitió recuperar hongos de los géneros Bipolaris, Fusarium, Purpureocillium, Curvularia, Phoma y Scytalidium. Conclusiones. No se ha encontrado bibliografía de los géneros Curvularia, Phoma y Scytalidium que describa la interacción de estos hongos con huevos de nematodos y queda, por tanto, el desafío de investigar cuál es su verdadera acción sobre estos huevos (AU)

Background. The use of different isolation techniques allows the recovery of fungi based on their ability to use selective substrates. The sprinkle method is a technique for the recovery of nematophagous fungi in the soil. These fungi are natural predators of nematodes and are widely distributed in nature. Aims. To detect possible fungi with nematophagous ability in the soil of city parks in Corrientes (Argentina). Methods. The soil samples were taken from an area of ground between two trees and to no more than 2 cm deep. The isolation was performed according to the sprinkle method with Toxocara canis eggs as bait. Results. Eighteen soil samples were collected, and 6 genera and 8 species of fungi were isolated. The sprinkle method, simple and efficient, has the advantage of using a small amount of untreated soil for the isolation of fungi that can grow on the eggs of geohelminths. The genera Bipolaris, Fusarium, Purpureocillium, Curvularia, Phoma and Scytalidium were isolated in this study. Conclusions. No other studies describing the interaction between the genera Curvularia, Phoma and Scytalidium with nematode eggs have been found in the literature, thus more studies are required to determine what is their real action on these eggs (AU)

[Toxocara canis eggs as bait for soil fungus in a subtropical city]. / Huevos de Toxocara canis como anzuelo para hongos geófilos en una ciudad subtropical.

BACKGROUND: The use of different isolation techniques allows the recovery of fungi based on their ability to use selective substrates. The sprinkle method is a technique for the recovery of nematophagous fungi in the soil. These fungi are natural predators of nematodes and are widely distributed in nature. AIMS: To detect possible fungi with nematophagous ability in the soil of city parks in Corrientes (Argentina). METHODS: The soil samples were taken from an area of ground between two trees and to no more than 2cm deep. The isolation was performed according to the sprinkle method with Toxocara canis eggs as bait. RESULTS: Eighteen soil samples were collected, and 6 genera and 8 species of fungi were isolated. The sprinkle method, simple and efficient, has the advantage of using a small amount of untreated soil for the isolation of fungi that can grow on the eggs of geohelminths. The genera Bipolaris, Fusarium, Purpureocillium, Curvularia, Phoma and Scytalidium were isolated in this study. CONCLUSIONS: No other studies describing the interaction between the genera Curvularia, Phoma and Scytalidium with nematode eggs have been found in the literature, thus more studies are required to determine what is their real action on these eggs.

Assessment of the presence of Toxocara eggs in soils of an arid area in central-western Argentina.

With the aim of studying the contamination of soils with eggs of Toxocara spp. in an arid area in the central-western region of Argentina, 76 soil samples were collected from 18 towns belonging to six provinces of central-western Argentina. They were processed by the centrifugal flotation method. No eggs of Toxocara spp. were found. It can be concluded that the negative results are directly related to the characteristics of the environment and climate present in the studied area. The finding of eggs in soils depends on several factors: the presence of canine or feline feces, the hygienic behavior of pet owners, the presence of stray animals without veterinary supervision, the weather and environmental conditions, and laboratory techniques used; and all these circumstances must be considered when comparing the results found in different geographical regions. In order to accurately define the importance of public spaces in the transmission of infection to humans, it is important to consider the role of backyards or green spaces around housing in small towns, where the population is not used to walking pets in public spaces, and in such cases a significant fraction of the population may acquire the infection within households.

Assessment of the presence of toxocara eggs in soils of an arid area in central-western Argentina / Evaluación de la presencia de huevos de Toxocara en suelos de una zona árida en la región centro-oeste Argentina

With the aim of studying the contamination of soils with eggs of Toxocara spp. in an arid area in the central-western region of Argentina, 76 soil samples were collected from 18 towns belonging to six provinces of central-western Argentina. They were processed by the centrifugal flotation method. No eggs of Toxocara spp. were found. It can be concluded that the negative results are directly related to the characteristics of the environment and climate present in the studied area. The finding of eggs in soils depends on several factors: the presence of canine or feline feces, the hygienic behavior of pet owners, the presence of stray animals without veterinary supervision, the weather and environmental conditions, and laboratory techniques used; and all these circumstances must be considered when comparing the results found in different geographical regions. In order to accurately define the importance of public spaces in the transmission of infection to humans, it is important to consider the role of backyards or green spaces around housing in small towns, where the population is not used to walking pets in public spaces, and in such cases a significant fraction of the population may acquire the infection within households.

Con el objetivo de estudiar la contaminación de los suelos con huevos de Toxocara spp, se obtuvieron 76 muestras de suelo de 18 pueblos pertenecientes a 6 provincias del centro-oeste de Argentina. Las muestras fueron procesadas por el método de centrifugación-flotación. No se encontraron huevos de Toxocara spp. en ninguna de las muestras de suelo. Llegamos a la conclusión de que los resultados negativos podrían estar en relación directa con las características ambientales y climáticas presentes en el área estudiada. El hallazgo o no de huevos en el suelo depende de varios factores: la presencia de heces de caninos o felinos, el comportamiento de los dueños de mascotas, la presencia de animales abandonados y sin control veterinario, las condiciones climáticas y ambientales y las técnicas de laboratorio utilizadas. Todas estas circunstancias deben ser consideradas cuando se comparan los resultados encontrados en diferentes regiones geográficas. Con el fin de definir la importancia que tienen los espacios públicos en la transmisión de la infección a los humanos, se debería considerar el papel que tienen los patios y veredas de las viviendas en las ciudades pequeñas, donde la población no acostumbra a pasear mascotas en parques y plazas, y en esos casos, la población puede adquirir la infección dentro de los hogares.

Prueba de avidez de los anticuerpos IgG en la infección por Toxocara canis / IgG antibodies avidity test in Toxocara canis infection / O teste de avidez dos anticorpos IgG na infecção por Toxocara canis

A fin de evaluar la utilidad de la prueba de avidez de los anticuerpos IgG para el reconocimiento de la fase de infección de la toxocariosis en individuos con alto nivel de exposición al parásito, se estudiaron 142 niños asintomáticos de ambos sexos, de 1-6 años de edad, residentes en la ciudad de Resistencia (NE de Argentina), con eosinofilia > 10% y con exámenes coproparasitológicos negativos para helmintos. Se realizó la prueba de ELISA-IgG en todos los casos y en aquellos con títulos > 1/80 se determinó el índice de avidez de IgG. De los 142 niños estudiados, 82 (57,7%) resultaron positivos a la prueba de ELISA-IgG pero sólo 6 (7.3%) tuvieron Índice de avidez menor al 50%, cinco tenían entre 1 y 2 años de edad y el restante 5 años (mediana: 1,5 años). Cuatro tuvieron títulos moderados de IgG (entre 1/80 y 1/640) y 2 títulos altos (entre 1/1280 y 1/10240). Los otros 76 niños con índice de avidez mayor al 50% tenían entre 18 meses y 5,5 años de edad (mediana: 4 años), 44 tuvieron títulos serológicos moderados y 32, títulos altos. Los resultados hallados en este trabajo reafirman que la población de la ciudad de Resistencia presenta altos niveles de exposición a T. canis y que la determinación del índice de avidez de IgG resulta útil para el diagnóstico diferencial entre toxocariosis reciente o tardía, aunque es más efectiva para descartar una infección reciente que para confirmarla.

In order to evaluate the usefulness of the IgG avidity test to recognize the phase of T. canis human infection in individuals highly exposed to the parasite, 142 asymptomatic children of both sexes, 1-6 years old, living in Resistencia (Northeastern Argentina), with eosinophilia > 10% and without helminthic intestinal infestation were studied. ELISA-IgG test was performed in all cases, and in those with serological titers > 1/80 IgG avidity was also measured. Out of 142 children studied, 82 (57.7%) were positive to ELISA test, but only 6 (7.3%) had an IgG avidity index < 50%. Five of them were aged between 1 to 2 years and the other was 5 years old (median 1.5 years). Four had moderate serological titers (between 1/80 and 1/640) and two had high titers (between 1/1280 and 1/10240). The other 76 children with IgG avidity indexes > 50% were between 18 months and 5.5 years old (median 4 years), 44 had moderate serological titers and 32 had high titers. The results found in this study reaffirm that the population in Resistencia city is highly exposed to T. canis infection and that the IgG avidity test may be helpful in differential diagnosis of recent and past toxocariosis, though it would be more effective to rule out a recently acquired infection than to confirm it.

Com o fim de avaliar a utilidade da prova de avidez dos Acs IgG para o reconhecimento da fase de infecção de toxocaríase em indivíduos com alto nível de exposição ao parasita, foram estudadas 142 crianças assintomáticas de ambos os sexos de 1 a 6 anos de idade, residentes na cidade de Resistencia (noreste argentino) com eosinofilia > 10% e com exames coproparasitológicos negativos para helmintos. Foi realizada a prova Elisa-IgG em todos os casos e naqueles com títulos > 1/80 foi determinado o índice de avidez de IgG. Das 142 crianças estudadas, 82 (57,7%) resultaram positivas à prova de Elisa-IgG porém só 6 (7,3%) tiveram índice de avidez < a 50%, 5 tinham entre 1 e 2 anos de idade e as outras 5 anos (média: 1,5 anos). Quatro tiveram títulos moderados de IgG (entre 1/80 e 1/640) e 2 títulos altos (entre 1/1280 e 1/10240). As outras 76 crianças com índice de avidez maior a 50% tinham entre 18 meses e 5,5 anos de idade (média: 4 anos), 44 tiveram títulos sorológicos moderados e 32 títulos altos. Os resultados encontrados neste trabalho reafirmam que a população da cidade de Resistencia apresenta altos níveis de exposição à T. canis e que a determinação do índice de avidez de IgG resulta útil para o diagnostico diferencial entre toxocaríase recente ou tardia, embora seja mais efetiva para descartar uma infecção recente que para confirmá-la.

Infección por Toxocara canis en población infantil vulnerable del noreste de Argentina Infección por Toxocara canis / No disponible

Fundamentos: La toxocariosis es una parasitosis producida por un geohelminto presente en todo el mundo con prevalencias variables. Se estudió la prevalencia de infección por T. canis y la situación epidemiológica de una población infantil vulnerable del NE de Argentina. Material y métodos: Se estudiaron 273 niños de 1-14 años de edad de la ciudad de Corrientes; de ellos, 96viven en un barrio carenciado y 177 en un Hogar-Escuela. Se investigó Acs-IgG anti-Toxocara canis, se recabó información epidemiológica y se analizaron factores de riesgo. Resultados: La prevalencia total de Ac anti-Toxocara fue del 61.5%; en niños del barrio fue 50.0%, en el Hogar-Escuela67.8% (p=0.004), en varones 66.7%, en mujeres 55.0% (p=0.049). El 82.3% de los hogares poseen perros, el98.5% disponen de agua potable de red; el 80.1% tienen piso de material, solo el 35.4% están conectadas a la red de alcantarillado, el 69.1% de la familias viven en condiciones de hacinamiento y el 73.6% de los padres no completaron el nivel de educación primaria. El análisis de la seropositividad en relación con los factores de riesgo demuestra asociación significativa con la falta de alcantarillado, con el contacto con perros y con la residencia en viviendas sin piso. Conclusiones: Las cifras encontradas revelan la necesidad de acciones de promoción comunitaria y del saneamiento del ambiente para garantizar bienestar y salud a los niños del área (AU)

Purposes: Toxocariosis is a parasitic disease produced by a geohelminth present worldwide with different prevalencerates. Prevalence of T. canis human infection and the epidemiological situation was estimated in a vulnerable infantile population in Northeast Argentina. Material and methods: A total of 273 children, 1 to 14 years old, from Corrientes city were studied; of them 96live in a poor neighborhood and 177 in a school-home during weekdays. Anti T. canis IgG by EIE, epidemiological data recording and the analysis of risk factors were performed. Results: Seroprevalence for the whole group was 61.5%, in children from poor neighborhood it was 50.0%, in children from the school-home 67.8% (p=0.004), in boys 66.7% and in girls 55.0% (p=0.049). Dogs are present in 82.3%of homes, 98.5% of the houses have pipeline-provided potable drinking water, 80.1% have paved floors inside home,35.4% have sewerage service, 69.1% of children live in overcrowding conditions and 73.6 % of the parent have not completed the elementary education level. Seroprevalence rates in relation to risk factors showed significant association with lack of sewerage facilities, with dogs contact and with unpaved-floor homes. Conclusions: Results reveal the need of actions for community promotion and for the improvement of environmental conditions, in order to assure welfare and a better health for the children of the area (AU)

Immunoblotting para diagnóstico de toxocarosis humana en un área subtropical / Immunoblotting for the diagnosis of human toxocarosis in a subtropical area

The diagnosis of toxocarosis is based upon the demonstration of antibodies by ELISA methods, although cross-reaction with other ascarids may occur in populations from tropical areas. For this reason, some authors proposed western blotting as a confirmatory test. The aim of this work was to develop an immunoblotting in simpler technical conditions and to compare results with the ELISA test. With this purpose sera from adults and children with sign and/or symptoms of toxocarosis and living in the metropolitan area of Resistencia city (Northeast of Argentina) were studied. ELISA test was performed and 120 positives and 60 negatives sera were selected and analyzed again by immunoblotting. Positive samples and controls showed a WB pattern with six bands of 67.6 kDa, 55.6 kDa, 43.9 kDa, 32.4 kDa, 26.6 kDa and 23.4 kDa, while negative controls from endemic and non-endemic areas of toxocarosis showed no bands. Out of the 180 samples studied, in 172 coincident results for both methods were obtained (95.6%), 6 ELISA negative samples were positive for WB (3.3%) and 2 ELISA positive samples resulted negative in the WB (1.1%). The immunoblotting technique described in this work may constitute an adequate method for the diagnosis of toxocarosis in subtropical areas, particularly useful in cases with negative or low-titers ELISA test results and with signs or symptoms of the infection.

El diagnóstico de toxocariosis se basa en la demostración de anticuerpos mediante enzimo-inmunoensayos, aunque en poblaciones de área tropicales suelen ocurrir reacciones cruzadas con otros ascáridos. Por ello algunos autores han propuesto el Western Blot como test confirmatorio. El objetivo de este trabajo fue desarrollar un método de immunoblotting con condiciones técnicas sencillas y comparar su comportamiento con la reacción de enzimoinmunoensayo. Se estudiaron 180 muestras de suero de adultos y niños con signo-sintomatología compatible con toxocariosis. Se efectuó test de ELISA con Antígenos TES, seleccionándose 120 sueros positivos y 60 negativos, los que fueron analizados nuevamente por immunobloting y se compararon los resultados de ambos métodos. Las muestras y controles positivos mostraron en el WB un patrón de seis bandas con PMs de 67,6 kDa, 55,6 kDa, 43,9 kDa, 32,4 kDa, 26,6 kDa y 23,4 kDa. Los sueros de control negativo de área endémica y no endémica de toxocarosis no mostraron banda alguna. De 180 muestras estudiadas, en 172 se obtuvieron resultados coincidentes por ambos métodos (95,6%), 6 muestras negativas por ELISA resultaron positivas por Western Blot (3,3%) y dos muestras positivas por ELISA fueron negativas por Western Blot (1,1%). El ensayo de immunoblotting acá descrito constituiría un método adecuado para el diagnóstico de toxocariosis en áreas sub-tropicales, particularmente útil en los casos en los que el test de ELISA resulte negativo o positivo con títulos bajos y en presencia de signos y/o síntomas de la infección.