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Argentina has a heterogeneous prevalence of infections by intestinal parasites (IPs), with the north in the endemic area, especially for soil-transmitted helminths (STHs). We analyzed the spatial patterns of these infections in the city of Tartagal, Salta province, by an observational, correlational, and cross-sectional study in children and adolescents aged 1 to 15 years from native communities. One fecal sample per individual was collected to detect IPs using various diagnostic techniques: Telemann sedimentation, Baermann culture, and Kato-Katz. Moran's global and local indices were applied together with SaTScan to assess the spatial distribution, with a focus on cluster detection. The extreme gradient boosting (XGBoost) machine-learning model was used to predict the presence of IPs and their transmission pathways. Based on the analysis of 572 fecal samples, a prevalence of 78.3% was found. The most frequent parasite was Giardia lamblia (30.9%). High- and low-risk clusters were observed for most species, distributed in an east-west direction and polarized in two large foci, one near the city of Tartagal and the other in the km 6 community. Spatial XGBoost models were obtained based on distances with a minimum median accuracy of 0.69. Different spatial patterns reflecting the mechanisms of transmission were noted. The distribution of the majority of the parasites studied was aligned in a westerly direction close to the city, but the STH presence was higher in the km 6 community, toward the east. The purely spatial analysis provides a different and complementary overview for the detection of vulnerable hotspots and strategic intervention. Machine-learning models based on spatial variables explain a large percentage of the variability of the IPs.

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BACKGROUND: Soil-transmitted helminths (STHs) are widely distributed throughout the world. Various factors, including the environment, socioeconomic characteristics, and access to water and sanitation, play an important role in the spread and persistence of these parasites within communities. They, in turn, affect the growth and development of members of the community, especially children. Studies in the northern provinces of Argentina have shown variable prevalence of STHs, but the factors associated with their presence have not been completely elucidated. OBJECTIVE: This cross-sectional study aimed to identify the socioeconomic and environmental factors related to STH infection in indigenous villages located in Puerto Iguazú (Misiones), Argentina. METHODS: Between 2018 and 2019, stool samples were collected from individuals ≥1 year residing in 3 villages: Mini-Marangatú, Yriapú, and Fortín Mbororé. Standard parasitological methods were used to determine STH prevalence. Standardized questionnaires were used to assess participants' habits, customs, and household characteristics, and environmental data were obtained through satellite imagery. Multilinear regression with Akaike information criterion stepwise variables was used to explore relevant associations. RESULTS: A total of 342 individuals from the 3 villages participated in this study. The prevalence of STHs varied across villages: 89.6% (43/48), in Mini-Marangatú, 80.8% (101/125) in Yriapú, and 68.5% (115/169) in Fortín Mbororé. Notably, there was a significant difference in hookworm infection among the villages (P=.02). The analysis highlighted the significant influence of specific environmental factors on STH presence and spatial distribution, particularly in relation to hookworm infection. Vegetation patterns represented by the Vegetation Heterogeneity Index, created ad hoc for this study, emerged as a critical factor, with 2 significant predictors related to it (P=.002 and P=.004) alongside impervious surface density with a significant predictor (P<.001). The multilinear regression model yielded a high F test score (F108=4.75, P<.001), indicating a strong fit (R2=0.5465). Furthermore, socioeconomic factors, including walking barefoot in houses with dirt floors and overcrowding, were significantly correlated with hookworm infection intensity (P<.001 and P=.001, respectively). We also used the multilinear regression model to calculate hookworm infection intensity (F110=21.15, P<.001; R2=0.4971). CONCLUSIONS: Our study underscores the complexity of STH transmission, as villages with similar living conditions and environmental characteristics displayed varied STH prevalence and spatial distribution. Specific environmental factors, such as vegetation pattern and impervious surface density, played major roles in STH presence, demonstrating the crucial relationship between environmental factors and hookworm infection distribution. Moreover, our findings emphasize the significant influence of socioeconomic factors on hookworm infection intensity. By gaining insights into this complex interplay, our research contributes to a better understanding of STH transmission characteristics, thereby informing targeted public health interventions for effective control.

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Strategies for the prevention of arboviral diseases transmitted by Aedes aegypti have traditionally focused on vector control. This remains the same to this day, despite a lack of documented evidence on its efficacy due to a lack of coverage and sustainability. The continuous growth of urban areas and generally unplanned urbanization, which favor the presence of Ae. aegypti, demand resources, both material and human, as well as logistics to effectively lower the population's risk of infection. These considerations have motivated the development of tools to identify areas with a recurrent concentration of arboviral cases during an outbreak to be able to prioritize preventive actions and optimize available resources. This study explores the existence of spatial patterns of dengue incidence in the locality of Tartagal, in northeastern Argentina, during the outbreaks that occurred between 2010 and 2020. Approximately half (50.8%) of the cases recorded during this period were concentrated in 35.9% of the urban area. Additionally, an important overlap was found between hotspot areas of dengue and chikungunya (Kendall's W = 0.92; p-value < 0.001) during the 2016 outbreak. Moreover, 65.9% of the cases recorded in 2022 were geolocalized within the hotspot areas detected between 2010 and 2020. These results can be used to generate a risk map to implement timely preventive control strategies that prioritize these areas to reduce their vulnerability while optimizing the available resources and increasing the scope of action.

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BACKGROUND: Chagas Disease (ChD) is a Neglected Tropical Disease (NTD) affecting 6 to 7 million people worldwide, mostly from Latin America. In Argentina, a national control program has been implemented since 1962, yet there are still an estimated 1.6 million infected individuals. Control programs were based almost exclusively on entomological surveillance and chemical control of households and were not continuous given a lack of coordination and resources. Argentina´s ChD program was originally vertical and centralized; later, it was partially and, in general, unsuccessfully transferred to the provinces. Herein, we describe the implementation of a control program for ChD with an ecohealth approach in rural settlements around the city of Añatuya, Santiago del Estero. METHODS: The program included yearly household visits for entomological surveillance and control, health promotion workshops, and structural house improvements. Improved structures included internal and external walls and roofs, as well as the construction of water wells and latrines, and the organization and improvement of peri-domestic structures. Activities were carried out by specifically trained personnel except for house improvements, which were performed by the community, under technical guidance and provision of materials. Data was collected using standardized questionnaires for household characterization, entomological infestation status and chemical control activities. RESULTS: This program was continuously implemented since 2005 with high community participation and adherence, incorporating 13 settlements and 502 households. During the surveillance phase, 4,193 domiciliary inspections were performed, and both the intra- and peri-domestic infestation rate were reduced from 17.9% to 0.2% (P < 0.01) and from 20.4% to 3%, respectively. Additionally, 399 households were structurally improved. CONCLUSION: The program is still ongoing and, after 14 years of implementation, has built social networks and collaboration between implementers and beneficiaries with a reduction of T. infestans infestation in the intra- and peri-domicile. This reduction, especially inside the household, has enabled access to diagnosis and treatment of the population, with minimal risk of re-infection.

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Neglected tropical diseases are a group of 20 disabling diseases, which, in particular, are the most common chronic infections in the most vulnerable people. This study aimed to characterize the infection by intestinal parasites (IPs) in dwellings from a peri-urban neighborhood in Pampa del Indio, Chaco (Argentina), and its association with socioeconomic and environmental variables. Single stool samples were collected from all individuals older than 1 year through household visits and processed using coprological sedimentation and flotation techniques. Standardized questionnaires were used at the household level to collect socio-economic information. Environmental variables were obtained from the Planetscope image, Landsat 8 images and remote sensors, while land-use layers were obtained through the use of a maximum likelihood algorithm. Stool samples were provided by 314 individuals. The prevalence of IPs found was 30.6% (n = 96), with a predominance of Giardia lamblia (12.7%, n = 40) and Hymenolepis nana (7.6%, n = 24). The only soil-transmitted helminth found was Strongyloides stercoralis with a 2.5% prevalence (n = 8). Individuals of adult age (> 18 years) were 0.65 times less likely to present parasitic infections with respect to children and adolescents. The only environmental variable that was closely associated with the presence of IPs, was the Normalized Difference Water Index (NDWI), a measure of humidity; being higher around houses with positive individuals. Most of the IPs found in this study were of water-borne transmission and those transmitted directly from person-to-person, therefore fecal contamination is present. We believe that the low prevalence of STH in this area, which requires a passage through the soil, is related to the environmental characteristics, which are unsuitable for the development/permanence of the infective stages of these parasites. The geospatial data and tools used herein proved to be useful for the study of the relationship between the different factors that influence the presence of IPs in a community, from an eco-health approach.

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Introduction: Canine soil-transmitted helminth (cSTH) parasites need specific environmental conditions to complete their life cycle. Toxocara canis and T. cati are the most important zoonotic cSTH, since they are the causal agents of human toxocariasis. Canine STHs are dispersed in feces from infected domestic and wildlife canines. In this study, the presence of STH in canine feces was evaluated in 34 crowded public parks and squares from San Juan Province (Argentina). Methods: Fecal samples were collected during different seasons in 2021-2022 and analyzed by standard coprological methods, including Sheather and Willis flotation and Telemann sedimentation. InfoStat 2020, OpenEpi V. 3.01 and R and RStudio® were used for statistical analysis and QGIS 3.16.10 for mapping. Results: From a total of 1,121 samples collected, 100 (8.9%) were positive for at least one intestinal parasite (IP) and three cSTH species were detected: Toxocara spp., Toxascaris leonina and Trichuris vulpis. The most prevalent cSTH species was T. vulpis (64/1121; 0.057%), while the least prevalent was Toxocara spp. (19/1121; 0.017%). The detection of Toxocara spp. eggs was significantly different depending on the season. The geo-spatial variation of each cSTH per season is described. Discussion: This is the first study in San Juan Province to identify environmental contamination of cSTHs in public areas. The specific localization of areas with the presence of cSTH eggs could provide information to guide strategies to reduce the cSTH infection burden in dogs and promote serological screening of the human population for Toxocara spp. Given the zoonotic nature of Toxocara spp. We hope this information will help to reinforce activities of control programs, focusing on the "One Health" approach.

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Ancylostoma caninum is a zoonotic nematode which is able to affect animals and humans. Diagnosis in the definitive host and environmental detection are key to prevent its dissemination and achieve control. Herein, a new coprological LAMP method for the detection of A. caninum (Copro-LAMPAc) DNA was developed. DNA extraction was performed using a low-cost method and a fragment of the cox-1 gene was used for primer design. The analytical sensitivity, evaluated with serial dilutions of genomic DNA from A. caninum adult worms, was 100 fg. A specificity of 100% was obtained using genomic DNA from the host and other pathogens. The Copro-LAMPAc was evaluated using environmental canine fecal samples. When compared with gold standard optical microscopy in epidemiological studies, it proved to be more sensitive. This new LAMP assay can provide an alternative protocol for screening and identification of A. caninum for epidemiological studies in endemic areas.

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BACKGROUND: The first case of SARS-CoV-2 was reported in Argentina on 3 March 2020. Measures to limit the spread of the virus were implemented, including complete lockdown (26 March). Nonetheless, the virus spread throughout the country, with a first peak of almost a million cases in October. On 30 November, the government's recommendation switched from social, preventive and compulsory isolation, to social, preventive and compulsory distancing. OBJECTIVES: To describe a tailored public health strategy to mitigate the spread of SARS-CoV-2 and determine its behaviour in San Antonio de Areco district from Buenos Aires province (Argentina) through a private-public association. DESIGN, SETTING AND PARTICIPANTS: Surveillance of the virus was performed with the local healthcare system, through early identification of cases and the systematic study of each infected individual and contact, regardless of symptomatology, using telemedicine and a COVID-19-specific outpatient clinic. Real-time PCR was used for detection using both individual and pooled samples, with a 12-hour turnaround time. RESULTS: Up to 30 November, a total of 2426 suspected cases were analysed and 578 were confirmed. Surveillance of health personnel and at-risk populations proved effective, mitigating viral spread. Pooling samples allowed reduction of operator time, helped reduce costs, and allowed detection of both symptomatic and asymptomatic cases. CONCLUSION: After 8 months of protocol implementation, the strategy to intensively survey groups at higher epidemiological risk and the systematic search for asymptomatic cases with the incorporation of pooled PCR for diagnosis, in combination with individual testing, is an efficient and viable option in populations with similar characteristics, in the frame of social isolation.

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Toxocariasis is a zoonotic disease caused mainly by Toxocara canis and Toxocara cati and diagnosis in dogs and cats is an important tool for its control. For this reason, a new coprological loop-mediated isothermal amplification (LAMP) assay was developed for the simultaneous detection of these species. The primer set was designed on a region of the mitochondrial cox-1 gene. Amplification conditions were evaluated using a temperature gradient (52°C to 68°C), different incubation times (15­120 min), and different concentrations of malachite green dye (0.004­0.4% w/v). The analytical sensitivity was evaluated with serial dilutions of genomic DNA from T. canis and T. cati adult worms, and with serial dilutions of DNA extracted from feces using a low-cost in-house method. The specificity was evaluated using genomic DNA from Canis lupus familiaris, Felis catus, Escherichia coli, Toxascaris leonina, Ancylostoma caninum, Echinococcus granulosus sensu stricto and Taenia hydatigena. The LAMP assay applied to environmental fecal samples from an endemic area showed an analytical sensitivity of 10­100 fg of genomic DNA and 10−5 serial dilutions of DNA extracted from feces using the low-cost in-house method; with a specificity of 100%. Additionally, the total development of the assay was carried out in a basic laboratory and per-reaction reagent cost decreased by ~80%. This new, low-cost tool can help identify the most common agents of toxocariasis in endemic areas in order to manage prevention strategies without having to rely on a laboratory with sophisticated equipment.

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[This corrects the article DOI: 10.1371/journal.pntd.0005574.].