[Human parasites in surface water used for recreation in Salta, Argentina]. / Parásitos humanos en aguas superficiales de uso recreativo en Salta, Argentina.

Waterborne diseases can have different origins, micro-organisms such as bacteria and parasites being the most important ones. In this study, two recreational aquatic environments were studied in the province of Salta, Argentina. Water samples collected from three different locations, two from a creek and one from the outlet of a thermal complex, were monitored at four time points. Physicochemical and microbiological characterization of each point was conducted, as well as a search for parasites and amebae. Parasites were identified through optical microscopy observations and free-living amebae (FLA) were isolated by spiking in Petri dishes followed by subsequent molecular identification. Water samples from the outlet of the thermal complex showed different physicochemical characteristics from those of the creek. Bacterial indicators of contamination were detected at all points; however, the creek water had a significantly higher concentration of Pseudomonas sp. Sporadically, creek samples exhibited Ascaris spp. eggs, Giardia sp. cysts, and ancylostomid eggs. The presence of FLA was observed in all samples, 15 of which were isolated and identified as Acanthamoeba sp., mostly belonging to the T4 genotype. Parasite surveillance in recreational aquatic environments is an important complement to traditional microbial indicators for assessing water quality. The identified parasites represent a potential health risk for people using these environments.

Minimizing errors in RT-PCR detection and quantification of SARS-CoV-2 RNA for wastewater surveillance.

Wastewater surveillance for pathogens using reverse transcription-polymerase chain reaction (RT-PCR) is an effective and resource-efficient tool for gathering community-level public health information, including the incidence of coronavirus disease-19 (COVID-19). Surveillance of Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) in wastewater can potentially provide an early warning signal of COVID-19 infections in a community. The capacity of the world's environmental microbiology and virology laboratories for SARS-CoV-2 RNA characterization in wastewater is increasing rapidly. However, there are no standardized protocols or harmonized quality assurance and quality control (QA/QC) procedures for SARS-CoV-2 wastewater surveillance. This paper is a technical review of factors that can cause false-positive and false-negative errors in the surveillance of SARS-CoV-2 RNA in wastewater, culminating in recommended strategies that can be implemented to identify and mitigate some of these errors. Recommendations include stringent QA/QC measures, representative sampling approaches, effective virus concentration and efficient RNA extraction, PCR inhibition assessment, inclusion of sample processing controls, and considerations for RT-PCR assay selection and data interpretation. Clear data interpretation guidelines (e.g., determination of positive and negative samples) are critical, particularly when the incidence of SARS-CoV-2 in wastewater is low. Corrective and confirmatory actions must be in place for inconclusive results or results diverging from current trends (e.g., initial onset or reemergence of COVID-19 in a community). It is also prudent to perform interlaboratory comparisons to ensure results' reliability and interpretability for prospective and retrospective analyses. The strategies that are recommended in this review aim to improve SARS-CoV-2 characterization and detection for wastewater surveillance applications. A silver lining of the COVID-19 pandemic is that the efficacy of wastewater surveillance continues to be demonstrated during this global crisis. In the future, wastewater should also play an important role in the surveillance of a range of other communicable diseases.

Quantification of viable protozoan parasites on leafy greens using molecular methods.

Protozoan contamination in produce is of growing importance due to their capacity to cause illnesses in consumers of fresh leafy greens. Viability assays are essential to accurately estimate health risk caused by viable parasites that contaminate food. We evaluated the efficacy of reverse transcription quantitative PCR (RT-qPCR), propidium monoazide coupled with (q)PCR, and viability staining using propidium iodide through systematic laboratory spiking experiments for selective detection of viable Cryptosporidium parvum, Giardia enterica, and Toxoplasma gondii. In the presence of only viable protozoa, the RT-qPCR assays could accurately detect two to nine (oo)cysts/g spinach (in 10 g processed). When different proportions of viable and inactivated parasite were spiked, mRNA concentrations correlated with increasing proportions of viable (oo)cysts, although low levels of false-positive mRNA signals were detectable in the presence of high amounts of inactivated protozoa. Our study demonstrated that among the methods tested, RT-qPCR performed more effectively to discriminate viable from inactivated C. parvum, G. enterica and T. gondii on spinach. This application of viability methods on leafy greens can be adopted by the produce industry and regulatory agencies charged with protection of human public health to screen leafy greens for the presence of viable protozoan pathogen contamination.

Making waves: Wastewater surveillance of SARS-CoV-2 for population-based health management.

Worldwide, clinical data remain the gold standard for disease surveillance and tracking. However, such data are limited due to factors such as reporting bias and inability to track asymptomatic disease carriers. Disease agents are excreted in the urine and feces of infected individuals regardless of disease symptom severity. Wastewater surveillance - that is, monitoring disease via human effluent - represents a valuable complement to clinical approaches. Because wastewater is relatively inexpensive and easy to collect and can be monitored at different levels of population aggregation as needed, wastewater surveillance can offer a real-time, cost-effective view of a community's health that is independent of biases associated with case-reporting. For SARS-CoV-2 and other disease-causing agents we envision an aggregate wastewater-monitoring system at the level of a wastewater treatment plant and exploratory or confirmatory monitoring of the sewerage system at the neighborhood scale to identify or confirm clusters of infection or assess impact of control measures where transmission has been established. Implementation will require constructing a framework with collaborating government agencies, public or private utilities, and civil society organizations for appropriate use of data collected from wastewater, identification of an appropriate scale of sample collection and aggregation to balance privacy concerns and risk of stigmatization with public health preservation, and consideration of the social implications of wastewater surveillance.

Potential of Bioremediation and PGP Traits in Streptomyces as Strategies for Bio-Reclamation of Salt-Affected Soils for Agriculture.

Environmental limitations influence food production and distribution, adding up to global problems like world hunger. Conditions caused by climate change require global efforts to be improved, but others like soil degradation demand local management. For many years, saline soils were not a problem; indeed, natural salinity shaped different biomes around the world. However, overall saline soils present adverse conditions for plant growth, which then translate into limitations for agriculture. Shortage on the surface of productive land, either due to depletion of arable land or to soil degradation, represents a threat to the growing worldwide population. Hence, the need to use degraded land leads scientists to think of recovery alternatives. In the case of salt-affected soils (naturally occurring or human-made), which are traditionally washed or amended with calcium salts, bio-reclamation via microbiome presents itself as an innovative and environmentally friendly option. Due to their low pathogenicity, endurance to adverse environmental conditions, and production of a wide variety of secondary metabolic compounds, members of the genus Streptomyces are good candidates for bio-reclamation of salt-affected soils. Thus, plant growth promotion and soil bioremediation strategies combine to overcome biotic and abiotic stressors, providing green management options for agriculture in the near future.

Simultaneous detection of four protozoan parasites on leafy greens using a novel multiplex PCR assay.

Pathogen contamination of fresh produce presents a health risk for consumers; however, the produce industry still lacks adequate tools for simultaneous detection of protozoan parasites. Here, a simple multiplex PCR (mPCR) assay was developed for detection of protozoan (oo)cysts and compared with previously published real-time PCR assays and microscopy methods. The assay was evaluated for simultaneous detection of Cryptosporidium, Giardia, Cyclospora cayetanensis, and Toxoplasma gondii followed by parasite differentiation via either a nested specific PCR or a restriction fragment length polymorphism (RFLP) assay. Spiking experiments using spinach as a model leafy green were performed for assay validation. Leaf-washing yielded higher recoveries and more consistent detection of parasites as compared with stomacher processing. Lowest limits of detection using the nested mPCR assay were 1-10 (oo)cysts/g spinach (in 10 g samples processed), and this method proved more sensitive than qPCR for parasite detection. Microscopy methods were more reliable for visual detection of parasites in lower spiking concentrations, but are more costly and laborious, require additional expertise, and lack molecular confirmation essential for accurate risk assessment. Overall, the nested mPCR assay provides a rapid (<24 h), inexpensive ($10 USD/sample), and simple approach for simultaneous detection of protozoan pathogens on fresh produce.

Construction of a combined soil quality indicator to assess the effect of glyphosate application.

Although the use of agrochemicals allowed increasing the crops productivity, in many cases led to soil deterioration. In this study, eight composite samples from different soils of two locations (San Martín and Anta) in Salta, Argentina, were collected and analyzed. All the samples were from loamy Entisols (0-20 cm depth) under reduced tillage without and with direct spray application of glyphosate. Twenty six variables were determined (physical, chemical, and biological soil quality indicators). From them, those of higher specificity and sensitivity to changes following glyphosate application were identified by a stepwise reduction of variables aided by statistical analysis. Samples were grouped regarding location and application of glyphosate, to identify differential effects upon variables, and glyphosate sensitive variables were selected by discarding those influenced by other factors. Thence, they were used to compose a first approximation to a combined soil quality indicator (CSQI) to assess the effect of glyphosate use in agriculture upon the soil. Overall, the set of physical variables showed the same discriminating structure as the biological set. Finally, two biological, two chemical, and two physical indicators resulted as the most specific to quality variations by the application of the herbicide, being the most sensitive the microbial biomass carbon and the (Aminomethyl)phosphonic acid concentration in soil. When these two were considered into a CSQI, it was possible to discriminate samples with the application of glyphosate (lower quality) from those without application (higher quality). To the best of our knowledge, this is the first attempt to propose a CSQI that could play an important role to prevent degradation in soils subjected to glyphosate application, as it could aid in the early detection of soil quality loss. This would provide to land managers a decision tool to let the land rest from glyphosate application, to ensure sustainable practices in agriculture.

Environmental hepatitis E virus detection supported by serological evidence in the northwest of Argentina.

Background: Hepatitis E virus (HEV) is an emergent cause of acute hepatitis worldwide. Water contamination is a possible source of viral infection. In South America, particularly in Argentina, little is known about environmental HEV circulation, including recreational water. The aim of this work was to provide evidence of current environmental and human circulation of HEV in northern Argentina. Methods: Molecular detection of HEV in water samples from the Arias-Arenales River in the city of Salta by nested polymerase chain reaction (ORF2 region) and anti-HEV immunoglobulin G (IgG) and IgM detection in the general population by enzyme-linked immunosorbent assay was carried out. Results: HEV RNA was detected in 1.6% (3/189) of the environmental samples. All sequences belonged to HEV genotype 3 and were very similar to those previously detected in the country. The prevalence of IgG anti-HEV was 9% (13/143) and three samples were positive for specific IgM. Conclusions: Circulation of HEV in the northwest of Argentina was demonstrated for the first time, showing viral presence in environmental samples and infections in people who attended health care centres for routine control. These findings show that recreational waters are a possible source of virus and highlight the need to carry out HEV detection when a case of hepatitis occurs.

Net growth rate of continuum heterogeneous biofilms with inhibition kinetics.

Biofilm systems can be modeled using a variety of analytical and numerical approaches, usually by making simplifying assumptions regarding biofilm heterogeneity and activity as well as effective diffusivity. Inhibition kinetics, albeit common in experimental systems, are rarely considered and analytical approaches are either lacking or consider effective diffusivity of the substrate and the biofilm density to remain constant. To address this obvious knowledge gap an analytical procedure to estimate the effectiveness factor (dimensionless substrate mass flux at the biofilm-fluid interface) was developed for a continuum heterogeneous biofilm with multiple limiting-substrate Monod kinetics to different types of inhibition kinetics. The simple perturbation technique, previously validated to quantify biofilm activity, was applied to systems where either the substrate or the inhibitor is the limiting component, and cases where the inhibitor is a reaction product or the substrate also acts as the inhibitor. Explicit analytical equations are presented for the effectiveness factor estimation and, therefore, the calculation of biomass growth rate or limiting substrate/inhibitor consumption rate, for a given biofilm thickness. The robustness of the new biofilm model was tested using kinetic parameters experimentally determined for the growth of Pseudomonas putida CCRC 14365 on phenol. Several additional cases have been analyzed, including examples where the effectiveness factor can reach values greater than unity, characteristic of systems with inhibition kinetics. Criteria to establish when the effectiveness factor can reach values greater than unity in each of the cases studied are also presented.

How long can culturable bacteria and total DNA persist in environmental waters? The role of sunlight and solid particles.

In this work, sunlight inactivation of two indicator bacteria in freshwater, with and without solid particles, was studied and the persistence of culturable cells and total DNA was compared. Environmental water was used to prepare two matrices, with and without solid particles, which were spiked with Escherichia coli and Enterococcus faecalis. These matrices were used to prepare microcosm bags that were placed in two containers: one exposed to sunlight and the other in the dark. During one month, samples were removed from each container and detection was done by membrane filter technique and real-time PCR. Kinetic parameters were calculated to assess sunlight effect. Indicator bacteria without solid particles exposed to sunlight suffered an immediate decay (<4h) compared with the ones which were shielded from them. In addition, the survival of both bacteria with solid particles varied depending on the situation analyzed (T99 from 3 up to 60days), being always culturable E. coli more persistent than E. faecalis. On the other side, E. faecalis DNA persisted much longer than culturable cells (T99>40h in the dark with particles). In this case active cells were more prone to sunlight than total DNA and the protective effect of solid particles was also observed. Results highlight that the effects caused by the parameters which describe the behavior of culturable microorganisms and total DNA in water are different and must be included in simulation models but without forgetting that these parameters will also depend on bacterial properties, sensitizers, composition, type, and uses of the aquatic environment under assessment.

Development of a relative risk model for drinking water regulation and design recommendations for a peri urban region of Argentina.

Argentina is a developing Latin American nation that has an aim of achieving the United Nations Millennium Development Goals for potable water supplies. Their current regulations however, limit the continued development of improved potable water quality and infrastructure from a microbiological viewpoint. This is since the current regulations are focused solely to pathogenic Eschericia coli (E. coli), Pseudomonas aeruginosa (P. aeruginosa) and fecal indicators. Regions of lower socioeconomic status such as peri-urban areas are particularly at risk due to lessened financial and political ability to influence their environmental quality and infrastructure needs. Therefore, a combined microbiological sampling, analysis and quantitative microbial risk assessment (QMRA) modeling effort were engaged for a peri-urban area of Salta Argentina. Drinking water samples from home taps were analyzed and a QMRA model was developed, results of which were compared against a general 1:10,000 risk level for lack of a current Argentinian standard. This QMRA model was able to demonstrate that the current regulations were being achieved for E. coli but were less than acceptable for P. aeruginosa in some instances. Appropriate health protections are far from acceptable for Giardia for almost all water sources. Untreated water sources were sampled and analyzed then QMRA modeled as well, since a significant number of the community (∼9%) still use them for potable water supplies. For untreated water E. coli risks were near 1:10,000, however, P. aeruginosa and Giardia risks failed to be acceptable in almost all instances. The QMRA model and microbiological analyses demonstrate the need for improved regulatory efforts for the peri-urban area along with improved investment in their water infrastructure.

Spatial and hydrologic variation of Bacteroidales, adenovirus and enterovirus in a semi-arid, wastewater effluent-impacted watershed.

Bacteroidales and viruses were contemporaneously measured during dry and wet weather conditions at a watershed-scale in a semi-arid watershed impacted by a mixture of agricultural runoff, municipal wastewater effluent and municipal runoff. The results highlight the presence of municipal wastewater effluent as a confounding factor for microbial source tracking (MST) studies, and thus data were segregated into groups based on whether they were impacted by wastewater effluent. In semi-arid environments such as the Calleguas Creek watershed, located in southern California, the relative contribution of municipal wastewater effluent is dependent on hydrology as storm events lead to conditions where agricultural and municipal stormwater dominate receiving waters (rather than municipal wastewater, which is the case during dry weather). As such, the approach to data segregation was dependent on hydrology/storm conditions. Storm events led to significant increases in ruminant- and dog-associated Bacteroidales concentrations, indicating that overland transport connects strong non-human fecal sources with surface waters. Because the dataset had a large number of non-detect samples, data handling included the Kaplan-Meir estimator and data were presented graphically in a manner that reflects the potential effect of detection limits. In surface water samples with virus detections, Escherichia coli concentrations were often below (in compliance with) the recreational water quality criteria. In fact, sites downstream of direct inputs of municipal wastewater effluent exhibited the lowest concentrations of E. coli, but the highest concentrations of human-associated Bacteroidales and highest detection rates of human viruses. The toolkit, comprised of the four Bacteroidales assays and human virus assays used, can be successfully applied to inform watershed managers seeking to comply with recreational water quality criteria. However, care should be taken when analyzing data to account for the effect of non-detect samples, sources with differing microbial viability, and diverging hydrologic conditions.

[Quantification of parasites in aquatic environments in the Province of Salta, Argentina]. / Cuantificación y evaluación de la estacionalidad de elementos parasitarios en ambientes acuáticos recreativos de la provincia de Salta, Argentina.

Microbiological pollution of recreational waters is a major problem for public health as it may transmit waterborne diseases. To assess water quality, current legislation only requires limits for bacterial indicators; however, these organisms do not accurately predict the presence of parasites. Small number of parasites is usually present in water and although they are capable of causing disease, they may not be high enough to be detected. Detection therefore requires water samples to be concentrated. In this work three recreational aquatic environments located in the province of Salta were monitored over one year. For parasite quantification, water samples were collected every three months and concentrated by ultrafiltration. Detection was performed by microscopy. In addition, monthly monitoring was carried out in each aquatic environment: physicochemical variables were measured in situ and bacteriological counts were determined by traditional microbiological techniques. Of 14 parasites identified, at least nine were detected in each aquatic environment sampled. While bacteriological contamination decreased in most cases during winter (76-99%), parasites were present year-round, becoming a continual threat to public health. Thus, we here propose that it is necessary to use specific parasitological indicators to prevent waterborne disease transmission. Our results suggest that Entamoeba would be a suitable indicator as it was found in all environments and showed minimal seasonal variation. The results obtained in this study have epidemiological relevance and will allow decision-makers to propose solutions for water protection in order to care for population health.

The continuum heterogeneous biofilm model with multiple limiting substrate Monod kinetics.

We describe a novel procedure to estimate the net growth rate of biofilms on multiple substrates. The approach is based on diffusion-reaction mass balances for chemical species in a continuum biofilm model with reaction kinetics corresponding to a Double-Monod expression. This analytical model considers a heterogeneous biofilm with variable distributions of biofilm density, activity, and effective diffusivity as a function of depth. We present the procedure to estimate the effectiveness factor analytically and compare the outcome with values obtained by the application of a rigorous numerical computational method using several theoretical examples and a test case. A comparison of the profiles of the effectiveness factor as a function of the Thiele modulus, φ, revealed that the activity of a homogeneous biofilm could be as much as 42% higher than that of a heterogeneous biofilm, under the given conditions. The maximum relative error between numerical and estimated effectiveness factor was 2.03% at φ near 0.7 (corresponding to a normalized Thiele modulus φ* = 1). For φ < 0.3 or φ > 1.4, the relative error was less than 0.5%. A biofilm containing aerobic ammonium oxidizers was chosen as a test case to illustrate the model's capability. We assumed a continuum heterogeneous biofilm model where the effective diffusivities of oxygen and ammonium change with biofilm position. Calculations were performed for two scenarios; Case I had low dissolved oxygen (DO) concentrations and Case II had high DO concentrations, with a concentration at the biofilm-fluid interface of 10 g O2 /m(3) . For Case II, ammonium was the limiting substrate for a biofilm surface concentration, CNs , ≤13.84 g of N/m(3) . At these concentrations ammonium was limiting inside the biofilm, and oxygen was fully penetrating. Conversely, for CNs > 13.84 g of N/m(3) , oxygen became the limiting substrate inside the biofilm and ammonium was fully penetrating. Finally, a generalized procedure to estimate the effectiveness factor for a system with multiple (n > 2) limiting substrates is given.

Cuantificación y evaluación de la estacionalidad de elementos parasitarios en ambientes acuáticos recreativos de la provincia de Salta, Argentina / Quantification of parasites in aquatic environments in the Province of Salta, Argentina

La contaminación microbiológica de aguas recreativas es un problema preocupante, ya que las personas que las utilizan pueden contraer enfermedades que podrían afectar su bienestar general. Para evaluar la calidad del agua, las legislaciones existentes solo establecen límites de indicadores bacterianos, los cuales no predicen con exactitud la presencia de parásitos. Además, la cantidad de parásitos presentes en el agua, aunque suficiente para producir enfermedad, suele ser pequeña, por lo que, se necesita una etapa previa de concentración para poder detectarlos. En este trabajo se monitorearon trimestralmente durante un año tres ambientes acuáticos de usos recreativos de la provincia de Salta, realizando la concentración de las muestras y la posterior preparación para la búsqueda de elementos parasitarios por microscopía. Adicionalmente, en cada ambiente se midieron mensualmente variables fisicoquímicas in situ y variables bacteriológicas por técnicas microbiológicas tradicionales. En cada ambiente se encontraron como mínimo 9 de los 14 parásitos detectados en conjunto. La presencia de los elementos parasitarios no presentó correlación con indicadores bacterianos en ningún ambiente ni en ninguna de las estaciones (p > 0,05). Mientras que en invierno la contaminación bacteriológica disminuyó entre un 76 % y un 99 %, los elementos parasitarios no presentaron disminución estacional. Los resultados permiten sugerir al género Entamoeba como indicador anual de contaminación parasitaria, ya que este fue encontrado en todos los ambientes con mínimas variaciones estacionales. Estos resultados poseen relevancia epidemiológica, dado que permitirán a los tomadores de decisiones proponer medidas para mejorar el bienestar de la población.

Microbiological pollution of recreational waters is a major problem for public health as it may transmit waterborne diseases. To assess water quality, current legislation only requires limits for bacterial indicators; however, these organisms do not accurately predict the presence of parasites. Small number of parasites is usually present in water and although they are capable of causing disease, they may not be high enough to be detected. Detection therefore requires water samples to be concentrated. In this work three recreational aquatic environments located in the province of Salta were monitored over one year. For parasite quantification, water samples were collected every three months and concentrated by ultrafiltration. Detection was performed by microscopy. In addition, monthly monitoring was carried out in each aquatic environment: physicochemical variables were measured in situ and bacteriological counts were determined by traditional microbiological techniques. Of 14 parasites identified, at least nine were detected in each aquatic environment sampled. While bacteriological contamination decreased in most cases during winter (76-99%), parasites were present year-round, becoming a continual threat to public health. Thus, we here propose that it is necessary to use specific parasitological indicators to prevent waterborne disease transmission. Our results suggest that Entamoeba would be a suitable indicator as it was found in all environments and showed minimal seasonal variation. The results obtained in this study have epidemiological relevance and will allow decision-makers to propose solutions for water protection in order to care for population health.

Cuantificación y evaluación de la estacionalidad de elementos parasitarios en ambientes acuáticos recreativos de la provincia de Salta, Argentina / Quantification of parasites in aquatic environments in the Province of Salta, Argentina

La contaminación microbiológica de aguas recreativas es un problema preocupante, ya que las personas que las utilizan pueden contraer enfermedades que podrían afectar su bienestar general. Para evaluar la calidad del agua, las legislaciones existentes solo establecen límites de indicadores bacterianos, los cuales no predicen con exactitud la presencia de parásitos. Además, la cantidad de parásitos presentes en el agua, aunque suficiente para producir enfermedad, suele ser pequeña, por lo que, se necesita una etapa previa de concentración para poder detectarlos. En este trabajo se monitorearon trimestralmente durante un año tres ambientes acuáticos de usos recreativos de la provincia de Salta, realizando la concentración de las muestras y la posterior preparación para la búsqueda de elementos parasitarios por microscopía. Adicionalmente, en cada ambiente se midieron mensualmente variables fisicoquímicas in situ y variables bacteriológicas por técnicas microbiológicas tradicionales. En cada ambiente se encontraron como mínimo 9 de los 14 parásitos detectados en conjunto. La presencia de los elementos parasitarios no presentó correlación con indicadores bacterianos en ningún ambiente ni en ninguna de las estaciones (p > 0,05). Mientras que en invierno la contaminación bacteriológica disminuyó entre un 76 % y un 99 %, los elementos parasitarios no presentaron disminución estacional. Los resultados permiten sugerir al género Entamoeba como indicador anual de contaminación parasitaria, ya que este fue encontrado en todos los ambientes con mínimas variaciones estacionales. Estos resultados poseen relevancia epidemiológica, dado que permitirán a los tomadores de decisiones proponer medidas para mejorar el bienestar de la población.(AU)

Microbiological pollution of recreational waters is a major problem for public health as it may transmit waterborne diseases. To assess water quality, current legislation only requires limits for bacterial indicators; however, these organisms do not accurately predict the presence of parasites. Small number of parasites is usually present in water and although they are capable of causing disease, they may not be high enough to be detected. Detection therefore requires water samples to be concentrated. In this work three recreational aquatic environments located in the province of Salta were monitored over one year. For parasite quantification, water samples were collected every three months and concentrated by ultrafiltration. Detection was performed by microscopy. In addition, monthly monitoring was carried out in each aquatic environment: physicochemical variables were measured in situ and bacteriological counts were determined by traditional microbiological techniques. Of 14 parasites identified, at least nine were detected in each aquatic environment sampled. While bacteriological contamination decreased in most cases during winter (76-99%), parasites were present year-round, becoming a continual threat to public health. Thus, we here propose that it is necessary to use specific parasitological indicators to prevent waterborne disease transmission. Our results suggest that Entamoeba would be a suitable indicator as it was found in all environments and showed minimal seasonal variation. The results obtained in this study have epidemiological relevance and will allow decision-makers to propose solutions for water protection in order to care for population health.(AU)

Cuantificación y evaluación de la estacionalidad de elementos parasitarios en ambientes acuáticos recreativos de la provincia de Salta, Argentina. / [Quantification of parasites in aquatic environments in the Province of Salta, Argentina].

Microbiological pollution of recreational waters is a major problem for public health as it may transmit waterborne diseases. To assess water quality, current legislation only requires limits for bacterial indicators; however, these organisms do not accurately predict the presence of parasites. Small number of parasites is usually present in water and although they are capable of causing disease, they may not be high enough to be detected. Detection therefore requires water samples to be concentrated. In this work three recreational aquatic environments located in the province of Salta were monitored over one year. For parasite quantification, water samples were collected every three months and concentrated by ultrafiltration. Detection was performed by microscopy. In addition, monthly monitoring was carried out in each aquatic environment: physicochemical variables were measured in situ and bacteriological counts were determined by traditional microbiological techniques. Of 14 parasites identified, at least nine were detected in each aquatic environment sampled. While bacteriological contamination decreased in most cases during winter (76-99

), parasites were present year-round, becoming a continual threat to public health. Thus, we here propose that it is necessary to use specific parasitological indicators to prevent waterborne disease transmission. Our results suggest that Entamoeba would be a suitable indicator as it was found in all environments and showed minimal seasonal variation. The results obtained in this study have epidemiological relevance and will allow decision-makers to propose solutions for water protection in order to care for population health.

[Intestinal parasitoses in Argentina: major causal agents found in the population and in the environment]. / Parasitosis intestinales en Argentina: principales agentes causales encontrados en la población y en el ambiente.

Intestinal parasitic diseases are widely spread in the world, with the highest prevalence in developing countries. Children are mainly affected, showing a decrease in physical and mental development, as well as the expected manifestations of the disease. This situation can be greatly enhanced in children with poor nutritional status. The World Health Organization considers intestinal parasitic diseases a major cause of morbidity, closely linked to poverty and poor personal hygiene, inappropriate handling of raw food, lack of sanitation, lack of potable water supply, and environmental fecal contamination. Some parasitic diseases are cosmopolitan while others have variable geographic distribution, due to different factors such as the presence of exclusive intermediate hosts. In the past few years, globalization allowed the spread of certain parasites from endemic to non-endemic regions. Even though people's customs influence on the frequency of certain parasites, environmental conditions are a determinant factor for parasite survival. In our country, due to the variety of soils and climatic conditions, several causative agents of these parasitoses can be found. The aim of this work was to review the literature on the intestinal parasitic agents found in Argentina in human fecal samples and its environment, as parasitic contamination constitutes a direct indicator of the infection risk by intestinal parasites.

Parasitosis intestinales en Argentina: principales agentes causales encontrados en la población y en el ambiente / Intestinal parasitoses in Argentina: Major causal agents found in the population and in the environment

Las parasitosis intestinales se encuentran ampliamente distribuidas en el mundo, con mayor prevalencia en los países en desarrollo. Principalmente afectan a los niños, en los que además provocan disminución del desarrollo físico y mental, situación que puede potenciarse enormemente cuando se suma a un estado nutricional deficiente. La Organización Mundial de la Salud las considera una de las principales causas de morbilidad, estrechamente ligada a la pobreza y relacionada con inadecuada higiene personal, incorrecta manipulación de los alimentos crudos, falta de servicios sanitarios, falta de provisión de agua potable y contaminación fecal del ambiente. Algunas enfermedades parasitarias se vinculan con condiciones de transmisión que existen universalmente, por lo que son cosmopolitas, mientras que otras tienen distribución geográfica variable. En los últimos años, debido a la globalización, el movimiento de personas de zonas endémicas a regiones no endémicas ha permitido la diseminación de ciertas parasitosis. Y aunque también influyen en la frecuencia de algunas de estas enfermedades las costumbres de los pueblos, las condiciones ambientales son un factor determinante para la supervivencia de los parásitos. En nuestro país, debido a la diversidad de suelos y condiciones climáticas que existen, es posible hallar variedad de agentes causales de estas parasitosis. El objetivo de este trabajo fue realizar una revisión bibliográfica de los agentes parasitarios causantes de enfermedades entéricas encontrados en la República Argentina, tanto en materia fecal de personas como en el ambiente, ya que la contaminación parasitaria de este último constituye un indicador directo del riesgo de infección por parásitos intestinales.

Intestinal parasitic diseases are widely spread in the world, with the highest prevalence in developing countries. Children are mainly affected, showing a decrease in physical and mental development, as well as the expected manifestations of the disease. This situation can be greatly enhanced in children with poor nutritional status. The World Health Organization considers intestinal parasitic diseases a major cause of morbidity, closely linked to poverty and poor personal hygiene, inappropriate handling of raw food, lack of sanitation, lack of potable water supply, and environmental fecal contamination. Some parasitic diseases are cosmopolitan while others have variable geographic distribution, due to different factors such as the presence of exclusive intermediate hosts. In the past few years, globalization allowed the spread of certain parasites from endemic to non-endemic regions. Even though people's customs influence on the frequency of certain parasites, environmental conditions are a determinant factor for parasite survival. In our country, due to the variety of soils and climatic conditions, several causative agents of these parasitoses can be found. The aim of this work was to review the literature on the intestinal parasitic agents found in Argentina in human fecal samples and its environment, as parasitic contamination constitutes a direct indicator of the infection risk by intestinal parasites.

Parasitosis intestinales en Argentina: principales agentes causales encontrados en la población y en el ambiente / Intestinal parasitoses in Argentina: Major causal agents found in the population and in the environment

Las parasitosis intestinales se encuentran ampliamente distribuidas en el mundo, con mayor prevalencia en los países en desarrollo. Principalmente afectan a los niños, en los que además provocan disminución del desarrollo físico y mental, situación que puede potenciarse enormemente cuando se suma a un estado nutricional deficiente. La Organización Mundial de la Salud las considera una de las principales causas de morbilidad, estrechamente ligada a la pobreza y relacionada con inadecuada higiene personal, incorrecta manipulación de los alimentos crudos, falta de servicios sanitarios, falta de provisión de agua potable y contaminación fecal del ambiente. Algunas enfermedades parasitarias se vinculan con condiciones de transmisión que existen universalmente, por lo que son cosmopolitas, mientras que otras tienen distribución geográfica variable. En los últimos años, debido a la globalización, el movimiento de personas de zonas endémicas a regiones no endémicas ha permitido la diseminación de ciertas parasitosis. Y aunque también influyen en la frecuencia de algunas de estas enfermedades las costumbres de los pueblos, las condiciones ambientales son un factor determinante para la supervivencia de los parásitos. En nuestro país, debido a la diversidad de suelos y condiciones climáticas que existen, es posible hallar variedad de agentes causales de estas parasitosis. El objetivo de este trabajo fue realizar una revisión bibliográfica de los agentes parasitarios causantes de enfermedades entéricas encontrados en la República Argentina, tanto en materia fecal de personas como en el ambiente, ya que la contaminación parasitaria de este último constituye un indicador directo del riesgo de infección por parásitos intestinales.(AU)

Intestinal parasitic diseases are widely spread in the world, with the highest prevalence in developing countries. Children are mainly affected, showing a decrease in physical and mental development, as well as the expected manifestations of the disease. This situation can be greatly enhanced in children with poor nutritional status. The World Health Organization considers intestinal parasitic diseases a major cause of morbidity, closely linked to poverty and poor personal hygiene, inappropriate handling of raw food, lack of sanitation, lack of potable water supply, and environmental fecal contamination. Some parasitic diseases are cosmopolitan while others have variable geographic distribution, due to different factors such as the presence of exclusive intermediate hosts. In the past few years, globalization allowed the spread of certain parasites from endemic to non-endemic regions. Even though peoples customs influence on the frequency of certain parasites, environmental conditions are a determinant factor for parasite survival. In our country, due to the variety of soils and climatic conditions, several causative agents of these parasitoses can be found. The aim of this work was to review the literature on the intestinal parasitic agents found in Argentina in human fecal samples and its environment, as parasitic contamination constitutes a direct indicator of the infection risk by intestinal parasites.(AU)