Microbiological hazard identification in river waters used for recreational activities.

Pathogenic bacteria, viruses, and parasites can cause waterborne disease outbreaks. The study of coastal water quality contributes to identifying potential risks to human health and to improving water management practices. The Río de la Plata River, a wide estuary in South America, is used for recreational activities, as a water source for consumption and as a site for sewage discharges. In the present study, as the first step of a quantitative microbial risk assessment of the coastal water quality of this river, a descriptive study was performed to identify the microbial pathogens prevalent in its waters and in the sewage discharged into the river. Two sites, representing two different potential risk scenarios, were chosen: a heavily polluted beach and an apparently safe beach. Conductivity and fecal contamination indicators including enterococci, Escherichia coli, F + RNA bacteriophages, and human polyomaviruses showed high levels. Regarding enterococci, differences between sites were significant (p-values <0.001). 93.3% and 56.5% of the apparently safe beach exceeded the recreational water limits for E. coli and enterococci. Regarding pathogens, diarrheagenic E. coli, Salmonella, and noroviruses were detected with different frequencies between sites. The parasites Cryptosporidium spp. and Giardia duodenalis were frequently detected in both sites. The results regarding viral, bacterial, and parasitic pathogens, even without correlation with conventional indicators, showed the importance of monitoring a variety of microorganisms to determine water quality more reliably and accurately, and to facilitate further studies of health risk assessment. The taxonomic description of microbial pathogens in river waters allow identifying the microorganisms that infect the population living on its shores but also pathogens not previously reported by the clinical surveillance system.

[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.

Biotechnological potential of microorganisms isolated from the salar del hombre muerto, Argentina.

Bacterial strains were isolated from soil and aqueous solution samples from the Salar del Hombre Muerto, Argentina. A total of 141 strains were characterized and the tolerance to sodium chloride was evaluated. We performed a screening to search for molecules of biotechnological interest: carotenoids (11%), emulsifiers (95%), and exopolysaccharides (6%), and to assess the production of enzymes, including proteolytic (39%), lipolytic (26%), hemolytic (50%), and catalase activities (99%); 25 bacterial strains were selected for further studies. Some of them produced biofilms, but only Bacillus sp. HA120b showed that ability in all the conditions assayed. Although 21 strains were able to form emulsions, the emulsifying index Kocuria sp. M9 and Bacillus sp. V3a cultures were greater than 50% and, emulsions were more stable when the bacteria grew in higher salt concentrations. Only pigmented Kocuria sp. M9 showed lipolytic activity on olive oil medium and was able to produce biofilms when cultured without and with 4 M of NaCl. Yellow pigments, lipase activity, and biosurfactant production were observed for Micrococcus sp. SX120. Summarizing, we found that the selected bacteria produced highly interesting molecules with diverse industrial applications and, many of them are functional in the presence of high salt concentrations.

Acanthamoeba and a bacterial endocytobiont isolated from recreational freshwaters.

The quality of many freshwater environments is impacted by human activities, so that many rivers may represent a vehicle for the transmission of health-related microorganisms. This work aimed to isolate and identify genetically free-living amoeba (FLA) of the genus Acanthamoeba from a recreational river in Salta, Argentina, and isolate, if possible, an endocytobiont. Sampling took place at four points (P1-P4) throughout the river in the winter and the summer seasons. Free-living amoebae and Acanthamoeba were recovered from 20-L water concentrated through an ultrafiltration system. Isolation was performed in agar plates, confirmation of Acanthamoeba genus by PCR, and fellow identification and classification based on their sequence analyses. High concentrations of indicator bacteria were found especially in P2, which is intensively used for recreation. Out of a total of 29 FLA isolations, 9 were identified as Acanthamoeba genotype T4 subtype A, the most frequent genotype found in nature and associated with causing human disease. From an axenic culture of Acanthamoeba spp. (KY751412), a bacterial endocytobiont was isolated, and identified as Stenotrophomonas maltophilia. The endocytobiont showed resistance and intermediate resistance to a wide range of widely used antibiotics. Results were in concordance with the cosmopolitan behavior of Acanthamoeba, and showed the importance of studying this group of amoebae and related microorganisms in recreational environments.

[Proposal for the control and mitigation of COVID-19 dissemination: strategic management of the disease]. / Propuestas para el control y la mitigación de la diseminación de COVID-19: un manejo estratégico de la enfermedad.

The rapid spread of COVID-19 throughout the world, has led most of the affected countries to close their borders and implement some form of lockdown. Six months after the pandemic started, many countries made decisions tending to relax the lockdown, although without a vaccine or treatment capable of confronting SARS-CoV-2 infection, the situation could be reversed at any time. In this context, the aim of this work was to propose a decision algorithm that will allow to optimize asymptomatic case detections and strategically manage quarantine to prevent the spread of the virus and drive the transition to a managed new normal. This tentative proposal was developed for optimizing and ordering the number of tests for the detection of SARS-CoV-2, analyzing composite samples (group analysis) combining with those samples individually taken from asymptomatic members of cohorts of interest. Cohorts were defined according to their critical role in society and/or their vulnerability. The algorithm includes variables such as cohort priority, number of cohort members in the analysis groups, intra-and intergroup contact, vulnerability to contagion due to the activity performed, and time elapsed since last testing. The proposed tool was illustrated with defined hypothetical cohorts, in which, for the sake of simplification, only one analysis group was considered. The application of this tool allowed to establish in a rational way a priority order to test critical groups in society. Furthermore, this tool would help to optimize resources, reducing the impact on a region's health, society, and economy.

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.

Halotolerant bacteria isolated from extreme environments induce seed germination and growth of chia (Salvia hispanica L.) and quinoa (Chenopodium quinoa Willd.) under saline stress.

The aim of the study was to characterize halotolerant bacteria and to evaluate their plant growth promotion potential on chia and quinoa seedlings under saline stress. Isolated microorganisms were evaluated for nitrogen fixation, phosphate solubilization, and production of siderophores and indole acetic acid. Three strains and two consortia were selected: Halomonas sp. (SFS), Micrococcus luteus (SA211), Bacillus sp. (HX11), C1 (SA211 + SFS), and C2 (SA211 + HX11). In vitro assays using water agar and half-strength Murashige-Skoog plates showed that an increase in salinity led to an increased seedlings mortality and a decrease in germination (lower than 40%), in total length (varying between 16% and 87% decreases), root length (from 60% to 92% lesser length) and dry weight (from 7% to 86% lower weight). Also, the relative growth index (RGI) decreased for both crops in most treatments, except those with HX11 and C2. These treatments had the highest growth parameters and RGI values in presence of high salinity in chia (50 and 100 mmol/L NaCl) and quinoa (200 and 400 mmol/L NaCl). SA211, the highest producer of indole acetic acid, showed a detrimental effect and anomalous phenotype on plants. Our results suggest that Bacillus sp. HX11, with multiple plant growth promotion traits and tolerance to saline stress, has a great potential as a bioinoculant in saline conditions and could be used as a biofertilizer for crop production.

Genetic fingerprint and diversity evaluation of halophilic Bacillus species by RAPD-PCR.

Random amplified polymorphic DNA-PCR (RAPD-PCR) is a technique successfully used to generate characteristic fingerprints of different bacteria. Bacillus is a genus that includes heterogeneous species, thus a combination of different techniques is essential for their identification. Here we used RAPD-PCR methodology to distinguish among genetically similar strains and to evaluate the genetic diversity of Bacillus species from the Salar del Hombre Muerto, in the Northwest of Argentina. The RAPD-PCR used allowed obtaining different amplification profiles for each Bacillus species and strains. By comparing the fingerprint profiles, we could observe that some of the salt flat isolates showed similar profiles than identified strains. As expected, the bacilli group isolated revealed a wide heterogeneity. RAPD-PCR was found to be a quick and reliable technique to evaluate the diversity of Bacillus strain and was successfully applied to characterize the genetic diversity present in the Salar del Hombre Muerto.

Rotavirus contamination of surface waters from the northwest of Argentina.

Fecal pollution of water is a serious concern because it is associated with the transmission of pathogens. The aim of this study was to analyze the occurrence of group A rotavirus (RVA) in surface waters from the Arias-Arenales River in Salta, a northern city in Argentina, and to define possible sources of fecal viral pollution. A total of 116 water samples were analyzed and RVA was detected in 3.4% (95% CI: 0.1-7.0%), with concentrations ranging from 1.9 × 105 to 3.8 × 106 genome copies per liter. RVA strains were characterized as G1P[8], G4P[8] and G9P[8], which are common genotypes circulating in the local population. The Arias-Arenales River presented unusual and sporadic contamination by RVA, originated from stormwater discharges and a variety of non-identified sources, and support the essential need of viral indicators for enhanced monitoring of water quality.

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.

Salar del Hombre Muerto, source of lithium-tolerant bacteria.

The Salar del Hombre Muerto is a flat salt with great microbial activity despite the existing extreme conditions like high altitude, lack of water, low level of oxygen, high radiation and high concentration of sodium and lithium chloride. Despite these unfavorable conditions, we found microbial diversity with the presence of fungi, algae, and bacteria. From aqueous solutions and soil samples, a total of 238 bacteria were isolated and 186 of them were able to grow in the presence of salt. About 30% of the strains showed the ability to grow in solid medium proximally to a LiCl solution close to saturation (636 g/L). These isolates were characterized taking into account the morphology, Gram stain, ability to form biofilms and to produce pigments, and mainly according to the tolerance against lithium chloride. Bacillus was predominant among the most tolerant 26 microorganisms found, followed by Micrococcus and Brevibacterium. Members of the genera Kocuria, Curtobacterium and Halomonas were also represented among the bacteria with tolerance to 30 and 60 g/L of LiCl in defined liquid medium. All the capacities found in these microorganisms make them extremely interesting for biotechnological applications.

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.

Isolation and characterization of indigenous Streptomyces and Lentzea strains from soils containing boron compounds in Argentina.

The Salta Province - in the northwest of Argentina - is the main worldwide producer of hydroboracite and leads in exports of boron mineral and its derivatives in Latin America. In addition to the natural presence of boron compounds in the soils, there are others contaminated due to the boron mining industry. Although some bacteria are known to require boron for their growth or to be capable of storing boron, no studies have been published about Streptomyces or Lentzea genera's capacity to tolerate high boron concentrations, or about their metabolic capacities in boron contaminated environments. The results of this research show the isolation and molecular characterization of eight strains belonging to the actinobacteria phylum collected from different soils contaminated with high boron concentration in Salta state. The boron tolerance assays, which show that three of the strains were able to tolerate up 60-80 mM boron, demonstrate the potential capability of this group of bacteria to grow and maybe to remove boron from the environment. They appear to be promising, considering that these microorganisms are infrequent pathogens, are metabolically versatile and many Streptomyces can synthesize boron containing metabolites.

Strategies to optimize monitoring schemes of recreational waters from Salta, Argentina: a multivariate approach.

Several recreational surface waters in Salta, Argentina, were selected to assess their quality. Seventy percent of the measurements exceeded at least one of the limits established by international legislation becoming unsuitable for their use. To interpret results of complex data, multivariate techniques were applied. Arenales River, due to the variability observed in the data, was divided in two: upstream and downstream representing low and high pollution sites, respectively, and cluster analysis supported that differentiation. Arenales River downstream and Campo Alegre Reservoir were the most different environments, and Vaqueros and La Caldera rivers were the most similar. Canonical correlation analysis allowed exploration of correlations between physicochemical and microbiological variables except in both parts of Arenales River, and principal component analysis allowed finding relationships among the nine measured variables in all aquatic environments. Variable's loadings showed that Arenales River downstream was impacted by industrial and domestic activities, Arenales River upstream was affected by agricultural activities, Campo Alegre Reservoir was disturbed by anthropogenic and ecological effects, and La Caldera and Vaqueros rivers were influenced by recreational activities. Discriminant analysis allowed identification of subgroup of variables responsible for seasonal and spatial variations. Enterococcus, dissolved oxygen, conductivity, E. coli, pH, and fecal coliforms are sufficient to spatially describe the quality of the aquatic environments. Regarding seasonal variations, dissolved oxygen, conductivity, fecal coliforms, and pH can be used to describe water quality during dry season, while dissolved oxygen, conductivity, total coliforms, E. coli, and Enterococcus during wet season. Thus, the use of multivariate techniques allowed optimizing monitoring tasks and minimizing costs involved.

[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.

MiDAS 5: Global diversity of bacteria and archaea in anaerobic digesters.

Anaerobic digestion of organic waste into methane and carbon dioxide (biogas) is carried out by complex microbial communities. Here, we use full-length 16S rRNA gene sequencing of 285 full-scale anaerobic digesters (ADs) to expand our knowledge about diversity and function of the bacteria and archaea in ADs worldwide. The sequences are processed into full-length 16S rRNA amplicon sequence variants (FL-ASVs) and are used to expand the MiDAS 4 database for bacteria and archaea in wastewater treatment systems, creating MiDAS 5. The expansion of the MiDAS database increases the coverage for bacteria and archaea in ADs worldwide, leading to improved genus- and species-level classification. Using MiDAS 5, we carry out an amplicon-based, global-scale microbial community profiling of the sampled ADs using three common sets of primers targeting different regions of the 16S rRNA gene in bacteria and/or archaea. We reveal how environmental conditions and biogeography shape the AD microbiota. We also identify core and conditionally rare or abundant taxa, encompassing 692 genera and 1013 species. These represent 84-99% and 18-61% of the accumulated read abundance, respectively, across samples depending on the amplicon primers used. Finally, we examine the global diversity of functional groups with known importance for the anaerobic digestion process.

Performance characteristics of qPCR assays targeting human- and ruminant-associated bacteroidetes for microbial source tracking across sixteen countries on six continents.

Numerous quantitative PCR assays for microbial fecal source tracking (MST) have been developed and evaluated in recent years. Widespread application has been hindered by a lack of knowledge regarding the geographical stability and hence applicability of such methods beyond the regional level. This study assessed the performance of five previously reported quantitative PCR assays targeting human-, cattle-, or ruminant-associated Bacteroidetes populations on 280 human and animal fecal samples from 16 countries across six continents. The tested cattle-associated markers were shown to be ruminant-associated. The quantitative distributions of marker concentrations in target and nontarget samples proved to be essential for the assessment of assay performance and were used to establish a new metric for quantitative source-specificity. In general, this study demonstrates that stable target populations required for marker-based MST occur around the globe. Ruminant-associated marker concentrations were strongly correlated with total intestinal Bacteroidetes populations and with each other, indicating that the detected ruminant-associated populations seem to be part of the intestinal core microbiome of ruminants worldwide. Consequently tested ruminant-targeted assays appear to be suitable quantitative MST tools beyond the regional level while the targeted human-associated populations seem to be less prevalent and stable, suggesting potential for improvements in human-targeted methods.

Increasing capacity for environmental engineering in Salta, Argentina.

BACKGROUND: The Fogarty International Center (FIC) of the United States National Institutes of Health includes the International Training and Research in Environmental and Occupational Health (ITREOH) Program. The "International Training Program in Environmental Toxicology and Public Health" Center, funded in 2002 is based at the University of California, Davis, and is part of the ITREOH group of Centers. It has major efforts focused at the public universities in Montevideo, Uruguay, and Salta, Argentina. RESULTS: Training and research efforts in Salta begun in 2005 in the College of Engineering. A donated used real-time PCR machine was the starting point and the initial FIC support was instrumental to face other problems including physical space, research projects and grants, trainees, training, networking, and distractions/opportunities in order to develop local capacities in Environmental Engineering using modern methodology. After 6 years of successful work, the Salta center has become a reference Center in the field, and is still growing and consolidating. CONCLUSIONS: This program has had a significant impact locally and regionally. The model used in Argentina could be easily adapted to other fields or types of projects in Argentina and in other developing countries.

Evaluation of concentration efficiency of the Pseudomonas aeruginosa phage PP7 in various water matrixes by different methods.

Enteric viruses monitoring in surface waters requires the concentration of viruses before detection assays. The aim of this study was to evaluate different methods in terms of recovery efficiencies of bacteriophage PP7 of Pseudomonas aeruginosa, measured by real-time PCR, using it as a viral control process in water analysis. Different nucleic acid extraction methods (silica-guanidinium thiocyanate, a commercial kit (Qiagen Viral RNA Kit) and phenol-chloroform with alcohol precipitation) exhibited very low recovery efficiencies (0.08-4.18 %), being the most efficient the commercial kit used for subsequent experiments. To evaluate the efficiency of three concentration methods, PBS (as model for clean water) and water samples from rivers were seeded to reach high (HC, 10(6) pfu ml(-1)) and low concentrations (LC, 10(4) pfu ml(-1)) of PP7. Tangential ultrafiltration proved to be more efficient (50.36 ± 12.91, 17.21 ± 9.22 and 12.58 ± 2.35 % for HC in PBS and two river samples, respectively) than adsorption-elution with negatively charged membranes (1.00 ± 1.34, 2.79 ± 2.62 and 0.05 ± 0.08 % for HC in PBS and two river samples, respectively) and polyethylene glycol precipitation (15.95 ± 7.43, 4.01 ± 1.12 and 3.91 ± 0.54 %, for HC in PBS and two river samples, respectively), being 3.2-50.4 times more efficient than the others for PBS and 2.7-252 times for river samples. Efficiencies also depended on the initial virus concentration and aqueous matrixes composition. In consequence, the incorporation of an internal standard like PP7 along the process is useful as a control of the water concentration procedure, the nucleic acid extraction, the presence of inhibitors and the variability of the recovery among replicas, and for the calculation of the sample limit of detection. Thus, the use of a process control, as presented here, is crucial for the accurate quantification of viral contamination.

[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.