Metropolitan Area Of Costa Rica Research Articles

Multidimensional assessment of a Nature-based Solution for decentralized greywater treatment in Costa Rica

In Costa Rica, water supply networks provide water to over 94% of the country's population. However, only an estimated 14% of wastewater receives proper treatment. The lack of centralized sanitation infrastructure has resulted in the use of septic tanks and the discharge of untreated greywater into rivers, causing environmental degradation of surface waters. Retrofitting conventional centralized sewer networks and treatment plants into the existing urbanization presents extensive social, economic, and technical challenges. Nature-based Solutions (NbS) for greywater treatment can reduce pollutant loads and improve the environmental status of water resources and represent an opportunity for technical leapfrogging towards sustainable, decentralized on-site treatment and reuse. However, the implementation of NbS in urban areas poses significant challenges due to the complex interplay of social, regulatory, and economic factors. Specifically, for on-site greywater treatment systems, meeting several criteria, including efficient pollutant removal, affordability, and public acceptance is essential for successful implementation and operation. This study assesses the technical, socio-economic, and political-regulatory dimensions relevant to implementing NbS for decentralized greywater treatment. To conduct this research, a Real-World Lab was established in the Great Metropolitan Area of Costa Rica, employing a transdisciplinary approach. This approach provided a physical space and societal context to integrate site-specific aspects and understand the various factors that influence the implementation and upscaling of NbS. As part of our methodology, we analyzed the water quality parameters and treatment performance of a NbS prototype for decentralized greywater treatment. Within the Real-World Lab framework, we conducted interviews, surveys, and field observations to investigate socio-economic and political-regulatory aspects. Our results highlight the technical potential of the NbS prototype. However, the limitation lies in the governance scheme and financing mechanisms required for upscaling the NbS as a decentralized on-site technology across the country. Our multidimensional assessment provides insights into the requirements for widespread implementation of NbS, applicable to other regions facing similar retrofitting sanitation challenges.

First record of Aulacaspis tubercularis (Hemiptera: Diaspididae) in Costa Rica, a scale insect affecting mango (Mangifera indica) in Alajuela urban environments

Introduction. Mango (Mangifera indica L.) is widely cultivated around the world and in Costa Rica nearly 8200 hectares are dedicated to the production of this crop. More than 400 species of phytophagous insects and mites have been reported on mango worldwide. Among them are around 73 species of armored scale insects (Hemiptera: Diaspididae), of which Aulacaspis tubercularis Newstead is one of the most serious pests of mangos in many parts of the world. Objective. In the present work, we report for the first time the occurrence in Costa Rica of the white mango scale, A. tubercularis. Materials and methods. Mango tree samples were collected in San Rafael, a town located in the central canton of Alajuela province in the Greater Metropolitan Area of Costa Rica. Insects found on leaves were examined under a stereomicroscope, counted and classified according to the condition of their wax covers, which provided evidence of activity by natural enemies. Slide mounts of adult females were prepared and examined under a light microscope. Results. The armored scale was identified as A. tubercularis and the frequency of occurrence on the mango trees sampled was 90%, where 12% of adult females showed evidence of predation and 2.5% showed evidence of parasitization. Conclusion. A. tubercularis was recorded for the first time in Costa Rica. Further investigations on the population dynamics and natural enemies are needed to provide useful information in order to implement adequate control strategies.

Assessing heavy metal pollution load index (PLI) in biomonitors and road dust from vehicular emission by magnetic properties modeling.

Vehicular traffic occupies a significant place among the sources of air pollution, due to population and urban growth that has led to an excessive increase in the vehicle fleet worldwide, and in Costa Rica as well. Vehicle emissions generate greenhouse gases (GHGs), particulate matter (PM), and heavy metals (HMs), due to combustion products from fossil-fuel engines, tire wear, and brake linings. HMs are important because they cannot be degraded or destroyed naturally; however, they can be diluted by physicochemical agents and be incorporated into trophic chains where they can be bioaccumulated causing significant negative effects on human well-being and ecological quality. This study aimed to assess the HM pollution load in biomonitors and road dust from vehicular emissions by chemical analyses and magnetic properties modeling. For this purpose, chemical and magnetic property analyses were carried out on samples of road dust and leaves of Cupressus lusitanica Mill. and Casuarina equisetifolia L., which were sampled during 2 different years in the Greater Metropolitan Area of Costa Rica known as GAM. Contamination factor (CF) and pollution load index (PLI) results showed significant metal pollution in some of the study sites. Contamination by the metals V, Cr, and Zn was most commonly present in the biomonitors, and for road dust, they were Cr, Zn, and Pb. The PLI estimates obtained with the validated support vector machine (SVM) magnetic properties models were consistent (sensitivity, specificity, and precision) with those obtained by chemical analysis, demonstrating the feasibility of this method for the identification of this index of contamination.

Percepção cidadã sobre segurança e visitação de espaços públicos: um estudo exploratório sobre parques públicos regionais na Costa Rica

Through an exploratory approach, this article aimed to investigate the relationship between uses, dynamics, and perception of security from users of three urban regional parks in the metropolitan area of Costa Rica. The information was collected from direct consultation through a closed survey and a predominantly quantitative analysis. One of the main findings highlights that about 60% of surveyed people visited the parks at least once a month. They come from various neighboring cantons, but especially those hosting the parks. In addition, fear of crime influences visitation patterns, especially the hours of use. Also, aspects such as gender and age influence this perception. Finally, it is concluded that existing evidence links the perception of security and visitation patterns to this type of space. Further studies of this type are necessary to have adequate inputs for planning and designing cities, especially in Latin America.

El impacto sobre la forma urbana de los nuevos proyectos de Vivienda de Interés Social en Costa Rica

In Costa Rica, the social housing (VIS) projects developed in the last decade have been located in areas far from urban centers of limited access to facilities and infrastructure due to the prohibitive cost of land ownership in most central sectors of metropolitan cities. The conditions and characteristics of these contexts, available land uses (zoning), morphological configurations, continuity and contiguity between social housing projects and the urban pieces where they are inserted, are analyzed in this research through the study of five residential complexes developed in the Greater Metropolitan Area of Costa Rica. The projects, built between 2011 and 2018, were analyzed from the study of construction plans, cartography of the area, documentary review and analysis of secondary data. From the obtained results it is possible to identify the main difficulties arising from the morphological and typological fit that followed after the establishment of the residential complexes, as well as the contextual problems derived from the location of the projects.

Water-Soluble Anions in PM10 Samples Collected in the Metropolitan Area of Costa Rica: Temporal and Spatial Variations

The concentrations of water-soluble anions present in PM10 collected from ambient air in four sites of Costa Rica’s greater metropolitan area (GAM) were analyzed. Samples were collected over a 24-h period for three days during the 2011–2018 period, using high-volume air samplers with mass flow controller. The PM10 samples were collected using quartz fiber filters, which were analyzed using ion chromatography to identify organic and inorganic ions. The annual averages for PM10, F−, Cl−, and SO42− showed significant differences between the sampling sites, with Uruca (UR) consistently registering annual averages above the maximum concentration established by Costa Rica’s air quality regulations (30 µgm−3). The ions analyzed contributed 33%, 34%, 35%, and 37% of the PM10 mass for sampling sites UR, HA, AL, and CA, respectively. Using Spearman correlations and principal component analysis (PCA), the following contributions were identified: biomass burning, secondary particle formation processes from mobile and stationary emissions, and biogenic emissions. For each variable, seasonal patterns and trends were analyzed using time series with additive decomposition.

High resolution modeling of the impact of urbanization and green infrastructure on the water and energy balance

Sealed surfaces in urban areas change the water and energy balance resulting in decreased evapotranspiration and infiltration, magnified stormwater runoff, and sensible heat fluxes. Urban Green Infrastructures (UGI) are implemented to reverse such effects. This study examines the potential of a high-resolution grid-based model to show the impact of different degrees of urban land cover. The study area was divided into 52 cells and cells were categorized into four urban degrees of urbanization. Two scenarios were considered to represent the existing conditions of a study area in the Great Metropolitan Area of Costa Rica and the effects derived from the implementation of UGI. The software Surface Urban Energy and Water Balance Scheme (SUEWS) was employed to simulate both scenarios and compare them by using the Bowen ratio (β) as an indicator of changes in the energy balance. The results show a reduction of β associated with the spatial distribution of the cells with different degrees of urbanization, even in the cells where no changes were considered. Applying the SUEWS approach based on high-resolved land cover classes distribution enables a more detailed understanding of micro-climatic benefits of UGI in high-density urban areas and may result in additional insights for decision-making.

Considerations on the meaning of organizational culture in a higher education institution

This paper advocates to determine the concept of organizational culture in a higher education institution located in the great metropolitan area of Costa Rica. In order to achieve the goals proposed, the research was preeminently conducted under a positivist paradigm, working under a non-experimental quantitative method and cross-sectional descriptive study. Moreover, the premise that the organizational culture of a collectivity plays a vital role when proposing, implementing, developing, and consolidating actions and activities, being these academic and outreach cultural and teaching programs.

Exposure forecasting for seismic risk estimation: Application to Costa Rica

This study proposes a framework to forecast the spatial distribution of population and residential buildings for the assessment of future disaster risk. The approach accounts for the number, location, and characteristics of future assets considering sources of aleatory and epistemic uncertainty in several time-dependent variables. The value of the methodology is demonstrated at the urban scale using an earthquake scenario for the Great Metropolitan Area of Costa Rica. Hundreds of trajectories representing future urban growth were generated using geographically weighted regression and multiple-agent systems. These were converted into exposure models featuring the spatial correlation of urban expansion and the densification of the built environment. The forecasted earthquake losses indicate a mean increase in the absolute human and economic losses by 2030. However, the trajectory of relative risk is reducing, suggesting that the long-term enforcement of seismic regulations and urban planning are effectively lowering seismic risk in the case of Costa Rica.

Co-design of experimental nature-based solutions for decentralized dry-weather runoff treatment retrofitted in a densely urbanized area in Central America

The quality of water in many urban rivers in Latin America is increasingly degrading due to wastewater and runoff discharges from urban sprawl. Due to deficits in sanitary drainage systems, greywater is discharged to the stormwater drainage network generating a continuous dry-weather runoff that reaches rivers without treatment. One of the main challenges in the region is to achieve sustainable management of urban runoff for the recovery of rivers ecosystem integrity. However, retrofitting conventional centralized wastewater drainage networks into the existing urban grid represents important social, economic and technical challenges. This paper presents an alternative adaptive methodology for the design of Nature-based Solutions for decentralized urban runoff treatment. Through this study, technical solutions commonly used for stormwater management were adapted for dry-weather runoff treatment and co-designed for the particular conditions of a representative study area, considering space availability as the main constraining factor for retrofitting in urban areas. The application of a co-design process in a dense neighbourhood of the Great Metropolitan area of Costa Rica brought to light valuable insights about conditions that could be hindering the implementation of NBS infrastructures in Latin America.

Development and modelling of realistic retrofitted Nature-based Solution scenarios to reduce flood occurrence at the catchment scale

Decentralized Nature-based Solutions such as Urban Green Infrastructures (UGI) are increasingly promoted to reduce flooding in urban areas. Many studies have shown the effectiveness of flood control of UGI at a plot or neighbourhood level. Modelling approaches that extrapolate their flood reducing impact to larger catchment scales are often based on a simplistic assumption of different percentages of UGI implementation. Additionally, such approaches typically do not consider the suitable space for UGI and potential implementation constraints. This study proposes a scenario development and modelling approach for a more realistic upscaling of UGI based on empirical insights from a representative neighbourhood. The results from this study, conducted in the metropolitan area of Costa Rica, show that upscaling the full potential for UGI could significantly reduce surface runoff, peak flows, and flood volumes. In particular, the permeable pavement has the highest potential for flood reducing in public space while cisterns perform best at the property level. These results can guide the formation of policies that promote UGI.

A New Theoretical and Methodological Look at Gender Differences in Mathematics Tests: Reasoning, Psychosocial Attitudes, and Multilevel Models

Acknowledging that gender, as a construct, is an expression of a power structure, observed differences favoring males were explained for two standardized tests of mathematical context: the Mathematics section of the University of Costa Rica’s Admission Test and the Mathematics test from the Secondary School’s Exit Exam. The sample was 487 students in the last year of high school in ten public schools from the Greater Metropolitan Area of Costa Rica; 269 were women. Multilevel regression models were estimated using the scores in these tests as dependent variables. The reduced model only included sex as a predictor, whereas the complete model included, additionally, an indicator of reasoning abilities and the following scales: hostile sexism, benevolent sexism, attitude toward gender equity in mathematics, and self-efficacy in mathematics. Results point out that gender differences are reduced by controlling for reasoning abilities. Benevolent sexism predicted performance in the tests to a lesser degree. There was also evidence of the moderating effect of the school for the relationship between sex and the score in the admission test, and, especially, for the means in the secondary school exit test. Mathematics self-efficacy also had considerable predictive power in the latter. These findings provide evidence of the need for teachers to actively promote self-efficacy in their students, especially women. The considerable differences in the average scores of the Secondary School’s Exit Exam, even though they are all public and from the Greater Metropolitan Area of Costa Rica, suggests the presence of inequities that should be studied more in-depth, including schools beyond this area, which could reveal even more disadvantages.

Experimenting Transition to Sustainable Urban Drainage Systems—Identifying Constraints and Unintended Processes in a Tropical Highly Urbanized Watershed

Green Infrastructure promotes the use of natural functions and processes as potential solutions to reduce negative effects derived from anthropocentric interventions such as urbanization. In cities of Latin America, for example, the need for more nature-based infrastructure is evident due to its degree of urbanization and degradation of ecosystems, as well as the alteration of the local water cycle. In this study, an experimental approach for the implementation of a prototype is presented. The prototype consists of a gray-hybrid element for first flush bio-treatment and runoff detention, adapted to the existing stormwater sewer. The experiment took place in a highly urbanized watershed located in the Metropolitan Area of Costa Rica. The characteristics of the existing infrastructure in the study area at different scales were mapped and compared using the Urban Water System Transition Framework. Subsequently, preferences related to spatial locations and technologies were identified from different local decision-makers. Those insights were adopted to identify a potential area for the implementation of the prototype. The experiment consisted of the adaptation of the local sewer to act as a temporal reservoir to reduce the effects derived from rapid generation of stormwater runoff. Unexpected events, not considered initially in the design, are reported in this study as a means to identify the necessary adaptations of the methodology. Our study shows from an experimental learning-experience that the relation between different actors advocating for such technologies influences the implementation and operation of non-conventional technologies. Furthermore, the willingness of residents to modify their urban environments was found to be associated to their own perceptions about security and vandalism occurring in green spaces. The implementation of the prototype showed that both the hydraulic performance is relevant for considering it as a success, as well as the dynamics of the adapted element with the existing urban conditions. In consequence, those aspects should be carefully considered as the design factors of engineering elements when they are related to complex socio-ecological urban systems.

Hydrometeorological disasters in urban areas of Costa Rica, Central America

ABSTRACT Tropical countries are subjected to natural disasters which cause substantial human and economic losses. Coping with disasters in tropics requires to improve our understanding of the frequency and distribution of hydrometeorological disaster events. These assessments are scarce in many developing countries, despite rapid urban expansion and lacking efficient public policies. Costa Rica’s location over the Intertropical Convergence Zone, its mountainous landscapes, and vulnerability generate risks conditions for urbans centers. Here, we analyze the Greater Metropolitan Area of Costa Rica (GAM in Spanish), a region that concentrates 65% of the national population. We analyze the hydrometeorological disasters occurrence and distribution in the GAM as well as a population and social indicators analysis to identify spatial patterns of demographic growth. Our results indicate that 5987 hydrometeorological disasters events were reported in the GAM between 1970 and 2018. From this total, 63.7% were floods, 35.3% landslides, 0.9% droughts and 0.1% storms. Coupling historical natural disasters and public policies to an urban sprawl continuous process in the GAM is a critical tool for land use planning and disaster risk reduction decision makers. Results from this study can enhance our understanding on the spatiotemporal characteristics of natural disasters in developing and/or tropical countries urban areas.

LeptospiraSeroprevalence Detection and Rabies Virus Absence in an Urban Raccoon (Procyon lotor) Population in a Highly Populated Area, Costa Rica

Leptospirosis and rabies are zoonotic diseases of public health importance and endemic diseases in tropical countries such as Costa Rica. Peridomestic wild animals such as raccoons (Procyon lotor) have been implicated as competent hosts of Leptospira spirochetes and rabies virus. This study focused on understanding the role of urban raccoons in the dynamics of leptospirosis and rabies in a tropical environment. A total of 97 specimens of the common raccoon were captured within the Greater Metropolitan Area of Costa Rica; 32.6% (31/95) of raccoons presented evidence of antibodies (> 1: 100) against Leptospira sp. Attempts to cultivate Leptospira failed, but 19 serovars were identified, which are also responsible for causing disease in humans in Costa Rica. Detected titers ranged from 1: 100 to 1: 6400. Lymphoid hyperplasia in kidneys and spirochetes were demonstrated in 3 of 20 necropsied cases (15%). Twenty brain samples were analyzed by hematoxylin and eosin stain for evidence of encephalitis and Negri body detection and simultaneously frozen brain material was employed to perform a rapid immunoassay test for rabies antigen. All tested samples were negative. This study is the first report of Leptospira seroprevalence in raccoons that cohabit urban areas in Costa Rica. We also highlight the importance of the raccoon as one of their natural competent host and sentinel animals within highly populated urban environments in tropical cities.

Salmonellosis detection and evidence of antibiotic resistance in an urban raccoon population in a highly populated area, Costa Rica.

Wild animals are involved in zoonotic disease transmission cycles. These are generally complex and poorly understood, especially among animals adapted to life in human ecosystems. Raccoons are reservoirs and effective carriers for infectious agents such as Salmonella throughout different environments and contribute to the transference of resistance genes. This study examined the presence of circulating Salmonella sp. in a population of raccoons in a tropical urban environment and evaluated resistance to antibiotics commonly used to treat salmonellosis. A total of 97 raccoons of different ages and sex were included in this study. 49% (38–60 CI) of the faecal samples were positive for Salmonella spp. The study identified 15 circulating serovars with the most prevalent being S. Hartford (7/15), S. Typhimurium (4/15) and S. Bovismorbificans (4/15). These serovars correspond to the serovars detected in humans with clinical symptoms in Costa Rica. 9.5% of the Salmonella strains recovered demonstrated ciprofloxacin resistance, and 7.1% showed resistance to nalidixic acid. This study provides evidence of multiple Salmonella serovars circulating in a population of urban raccoons in Costa Rica. Furthermore, the study confirms the existence of antimicrobial resistance to two antibiotics used to treat human salmonellosis. The findings emphasize the role of the raccoon as a reservoir of Salmonella in the Greater Metropolitan Area of Costa Rica (GAM) and stress the need for active monitoring of the presence and possible spread in antibiotic resistance due to this peri‐domestic carnivore.

Teaching Hands-Only CPR in Schools: A Program Evaluation in San José, Costa Rica

Background:Hands-only bystander CPR increases survival from out-of-hospital cardiac arrest. Video-based CPR instruction in schools has been proposed as a means to mass-educate laypersons in Hands-only CPR™ (HOCPR), in developed as well as developing countries.Objectives:The purpose of this study is to determine whether a brief video- and mannequin-based instructional program, developed by the American Heart Association (AHA), is an effective strategy for teaching Costa Rican middle- and high-school age children to learn the steps of HOCPR.Methods:This study took place in four educational centers that spanned the entire socioeconomic spectrum within the Grand Metropolitan Area of Costa Rica. Three hundred and eight students from the sixth to eleventh grades participated. The intervention included exposure to the AHA “CPR Anytime” video and practice with CPR mannequins. Before and after the intervention, students took a four-question, multiple-choice quiz that measured their knowledge of the correct steps and proper techniques of HOCPR; a separate question assessed their level of comfort “doing CPR on someone with a cardiac arrest.” Pre- and post-intervention “percent correct” scores were compared and tested for statistical significance using paired t-tests or the McNemar test as appropriate. Improvement in knowledge and comfort levels were also compared across the different educational centers and compared with similar programs implemented in the United States.Results:The students’ overall scores (mean percent correct) on the multiple choice questions more than doubled after training (40.9% ± 1.4% before training vs. 92.5% ± 0.9% after training, p < 0.00001). Improvements were observed in each school, regardless of geographic location or socioeconomic status. Knowledge of the appropriate steps of HOCPR doubled after training (42.2% before training vs. 92.5% after training, p < 0.000001). Post-intervention, a majority (73%) of children reported comfort with performing CPR on an individual who had suffered a cardiac arrest.Conclusion:This study demonstrates the effectiveness of the AHA “CPR Anytime” program in teaching HOCPR to school-age children within the Grand Metropolitan Area of Costa Rica. Additional studies are needed to measure longer-term knowledge retention and students’ ability to perform CPR in simulated cardiac arrest settings.

Respuestas macroinvertebrados acuáticos a la presión humana en una cuenca tropical volcánica alta: Río Birrís, Volcán Irazú (Costa Rica)

Background. Tropical mountain rivers are strategic sources of water for human development while biological communities are indicators of the status of these ecosystems. However, volcanic basins close to large urban areas are affected by increasing human pressures that threaten the future of these ecosystems and their benefits to society. Goals. This paper analyzes the evolution of the responses of the aquatic macroinvertebrate assemblages in the face of increasing pressures in the Birris River basin, which is essential for providing food and energy for the Greater Metropolitan Area of Costa Rica. The hypothesis that volcanic headwater communities are highly vulnerable to human impacts was tested. Methods. Composition and structure of aquatic macroinvertebrate assemblages were assessed along main river channels over two years. Results. The spatial variability of assemblages was related to organic pollution and the self-purification capacity of the river. Temporal variability was mainly explained by the intra-annual climate variability (seasonality). Macroinvertebrate assemblages were dominated by Chironomidae (Diptera), Simuliidae (Diptera), and Baetidae (Ephemeroptera) throughout the year. High flows during the rainy season (May to December) reduced density while diversity peaked at the end of that season. Ephemeroptera and Trichoptera reached their maximum abundance during the dry season, while Diptera showed maximum richness at the end of the rainy season. Conclusions. Biological communities showed spatial and temporal adaptations to the main environmental stresses, including high levels of organic pollution. However, the high slope of river channels favors the self-purification processes, which offer an opportunity for the recovery of ecological integrity combined with control of the organic discharges. More information is needed on taxonomy and autoecology of aquatic fauna and flora in these fragile volcanic environments that are strategic for the protection of water resources in the tropics.

Prevalence and Severity of Plaque-Induced Gingivitis in Three Latin American Cities: Mexico City-Mexico, Great Metropolitan Area-Costa Rica and Bogota-Colombia

Plaque-induced gingivitis is the most common form of periodontal disease and can affect 100% of the population. Gingivitis prevalence in Latin American population is not well documented, therefore the aim of this study was to determine the prevalence and severity of plaque-induced gingivitis in adult populations of three Latin American cities. Methods: This cross sectional multicenter study included 1650 participants, 550 from the Great Metropolitan Area of Costa Rica (GAM), 550 from Mexico City, Mexico (CDMX) and 550 from Bogota City, Colombia (BC). Subjects completed a questionnaire about their medical history and oral hygiene. Clinical assessment included recording of missing teeth, visible plaque index, calculus recording and gingival index (GI, Loe-Silness index). Results: Average GI was 1.36. No statistical difference was found between GAM (1.45) and BC (1.48); however, GI in CDMX was significantly lower (1.16). Average gingival bleeding on probing was 43%. Total plaque index was 0.76 showing the highest accumulation at interproximal sites (p=0.0001). A positive correlation was found between plaque and gingivitis (r=0.59). Dental calculus was present in at least one of the 18 evaluated sites per subject with no statistical difference between cities. There was no statistical difference in GI between smokers, former smokers and non- smokers. Conclusion: Gingivitis prevalence was 99.6%. Moderate Gingivitis was the predominant form, with no statistically significant difference between cities or gender. Dental plaque accumulation was the most important risk factor associated with the establishment of the disease.

Prevalence and Severity of Plaque-Induced Gingivitis in Three Latin American Cities: Mexico City-Mexico, Great Metropolitan Area-Costa Rica and Bogota-Colombia

Plaque-induced gingivitis is the most common form of periodontal disease and can affect 100% of the population. Gingivitis prevalence in Latin American population is not well documented, therefore the aim of this study was to determine the prevalence and severity of plaque-induced gingivitis in adult populations of three Latin American cities. Methods: This cross sectional multicenter study included 1650 participants, 550 from the Great Metropolitan Area of Costa Rica (GAM), 550 from Mexico City, Mexico (CDMX) and 550 from Bogota City, Colombia (BC). Subjects completed a questionnaire about their medical history and oral hygiene. Clinical assessment included recording of missing teeth, visible plaque index, calculus recording and gingival index (GI, Loe-Silness index). Results: Average GI was 1.36. No statistical difference was found between GAM (1.45) and BC (1.48); however, GI in CDMX was significantly lower (1.16). Average gingival bleeding on probing was 43%. Total plaque index was 0.76 showing the highest accumulation at interproximal sites (p=0.0001). A positive correlation was found between plaque and gingivitis (r=0.59). Dental calculus was present in at least one of the 18 evaluated sites per subject with no statistical difference between cities. There was no statistical difference in GI between smokers, former smokers and non- smokers. Conclusion: Gingivitis prevalence was 99.6%. Moderate Gingivitis was the predominant form, with no statistically significant difference between cities or gender. Dental plaque accumulation was the most important risk factor associated with the establishment of the disease.