Evaluation of neighborhood treatment systems for potable water supply.

Piped water is available in Ciudad Juarez, Chihuahua, Mexico, but residual disinfectant is not reliably found in the public drinking water supply. Lack of confidence in the public supply leads many residents to rely on bottled water. To provide consistent disinfection, two health clinics were equipped with ultraviolet disinfection systems, and neighboring households were encouraged to obtain their drinking water from the treatment systems. Use of the treated water declined from 62% of self-selected study participants at the time of the first visit to 40% at the second visit. During the first visit, diarrhea prevalence was similar among households using treated water and other water sources yet diarrhea prevalence was higher among households using the treated water during the second visit. Microbiological quality of the treated water in the homes was not demonstrably superior to that of other sources.

Carbon monoxide exposure in households in Ciudad Juárez, México.

This study assessed exposure to carbon monoxide from gas and wood heater emissions in a sample of 64 households in peri-urban residential areas in Ciudad Juárez, Chihuahua, México. Indoor and outdoor carbon monoxide concentrations and temperatures were monitored for a continuous period of 1 week at 1 and 6-min intervals, respectively. The moving average carbon monoxide concentrations were compared to the World Health Organization (WHO) standards for carbon monoxide. Sixty-seven percent of households with gas heaters and 60% of households with wood heaters exceeded a health-based standard at some point during the monitoring. The difference between indoor and outdoor temperatures was modestly correlated with average carbon monoxide exposure (r=0.35, p-value <0.01). Heater type may be a stronger determinant of exposure, as households with a particular heater model (the El Sol FM-210) were significantly more likely to be among the more highly exposed households (odds ratio of 4.8, p-value of 0.02). A variety of health effects were pooled and found at elevated frequency in the households that exceeded the 8-h standard of 9ppm (odds ratio=5.1, p-value=0.031). These results highlight the need for further efforts to identify and mitigate potentially hazardous carbon monoxide exposures, particularly in moderate-income countries with cooler climates.

Hyperendemic Cryptosporidium and Giardia in households lacking municipal sewer and water on the United States-Mexico border.

This study identified differences in the epidemiology of Giardia and Cryptosporidium infection for low-income populations residing on the United States-Mexico border. Participation included 77 households in three communities lacking adequate municipal water and sewage services. The household was the unit of analysis and sampling was from household biosolid waste from newly installed composting toilets. The proportion of households positive for Giardia and Cryptosporidium was high, 82% and 70%, respectively, and this was in contrast to the few households (14%) reporting at least one individual with diarrhea symptoms. This finding indicated that most of the participant families were chronically infected but asymptomatic. In the multivariate analysis, there was a statistically significant protective effect for Cryptosporidium in those households that purified drinking water but not for Giardia. Those households with children less than five years of age were 1.3 times at risk for Giardia infection. Our findings highlighted differences in the transmission mode of these two pathogens and underscore the need for interventions addressing hygiene, water supply, and sanitation.

Peri-urbanization and in-home environmental health risks: the side effects of planned and unplanned growth.

Urbanization is occurring at an explosive rate, and many cities, especially in low-income countries, are struggling to control growth and stop the development of unplanned communities. This research investigates the in-home environmental health risks associated with planned and unplanned growth in peri-urban communities (neighborhoods) of a rapidly growing city in Northern Mexico. Surveys were conducted during home visits to 98 households in a planned community and 202 households in unplanned communities of comparable, though slightly higher, socio-economic status. To assess the differences for the two types of communities, multiple risk factors were measured and compared. Results showed that households in both planned and unplanned communities were vulnerable to poor environmental health conditions, but more risk factors and negative health outcomes were associated with unplanned communities. Some of the obvious benefits of living in a planned community included better-constructed homes and water and sewer connections. Other study results indicated that households in the planned community reported fewer cases of respiratory problems (P = 0.039) and dizziness (P = 0.009). They were also less likely to store insecticides and other chemicals inappropriately in their home (P < 0.001). Providing adequate housing infrastructure appears to provide a number of important benefits to health and behavior beyond the simple provision of additional amenities in the home.

Applying the mental models framework to carbon monoxide risk in northern Mexico.

OBJECTIVES: Low-income residents of northern Mexico rely on unvented heaters during the winter, a practice that puts them at elevated risk for carbon monoxide intoxication. The goal of this study is to develop a communication protocol for carbon monoxide intoxication risks among the primarily low socioeconomic status population of Ciudad Juárez, Chihuahua, Mexico. METHODS: The mental models risk communication approach was used to identify important gaps in public understanding. This approach consists of step-by-step assessment of information needs and effectiveness of risk communication efforts by using interviews and surveys. RESULTS: The mental models process uncovered a key technical misunderstanding, the subject population's belief that carbon monoxide can be seen or smelled, which may result in a risk-prone behavior: failure to use a carbon monoxide detector. A communication protocol was designed to address this and other knowledge gaps, and it produced significant improvements in subjects' knowledge in a pretest/posttest evaluation. CONCLUSIONS: The mental models process was successful in developing a communication instrument capable of improving knowledge in the subject population. Future research needs include assessing the extent to which this instrument succeeds in changing behavior and reducing the risk of carbon monoxide intoxication. Future interventional efforts may focus on encouraging people to use carbon monoxide detectors.

The in-home environment and household health: a cross-sectional study of informal urban settlements in northern México.

People living in poverty make up nearly half of the global population and a large proportion of these individuals inhabit cities, living in informal settlements. However, only limited research on in-home environmental exposures and the associated health effects in these communities is available. This research investigates the home environment in unplanned settlements of a rapidly growing city on the U.S.-México border and its impact on the health of households with children under 12 years of age. A cross-sectional design was used to assess household exposures and health outcomes at the household level. A total of 202 households were selected from two informal settlements in the peri-urban region of Ciudad Juárez, México. The following variables were significantly associated with the report of at least one household member experiencing a health outcome in a two week period. Allergies were positively associated with insecticide use inside the home (adjusted Relative Odds (RO), 2.71; 95% confidence interval (CI), 1.2-6.3). Respiratory problems were associated with households using a wood burning stove vs. a gas stove (adjusted RO, 5.64; 95% CI, 1.1-27.9). Diarrhea was negatively associated with presence of a flush toilet in the home (adjusted RO, 0.22; 95% CI,0.1-0.6). Finally, eye irritations were positively associated with indoor tobacco smoke (adjusted RO, 2.23; 95% CI, 1.1-4.5). This research highlights exposures associated with poor living conditions in informal settlements and their associations with detrimental effects on health. More efforts should be made to understand the dynamics of poor urban environments including the health effects of exposures linked with poor housing conditions.

Applying the mental models framework to carbon monoxide risk in northern Mexico / Aplicación del enfoque de los modelos mentales al riesgo por monóxido de carbono en el norte de México

OBJECTIVES: Low-income residents of northern Mexico rely on unvented heaters during the winter, a practice that puts them at elevated risk for carbon monoxide intoxication. The goal of this study is to develop a communication protocol for carbon monoxide intoxication risks among the primarily low socioeconomic status population of Ciudad Juárez, Chihuahua, Mexico. METHODS: The mental models risk communication approach was used to identify important gaps in public understanding. This approach consists of step-by-step assessment of information needs and effectiveness of risk communication efforts by using interviews and surveys. RESULTS: The mental models process uncovered a key technical misunderstanding, the subject population's belief that carbon monoxide can be seen or smelled, which may result in a risk-prone behavior: failure to use a carbon monoxide detector. A communication protocol was designed to address this and other knowledge gaps, and it produced significant improvements in subjects' knowledge in a pretest/posttest evaluation. CONCLUSIONS: The mental models process was successful in developing a communication instrument capable of improving knowledge in the subject population. Future research needs include assessing the extent to which this instrument succeeds in changing behavior and reducing the risk of carbon monoxide intoxication. Future interventional efforts may focus on encouraging people to use carbon monoxide detectors.

OBJETIVOS: Los residentes de bajos ingresos del norte de México dependen durante el invierno de calefactores no ventilados, una práctica que los pone en mayor riesgo de intoxicación por monóxido de carbono. Se elaboró un protocolo de comunicación sobre los riesgos de intoxicación por monóxido de carbono en la población fundamentalmente de bajo nivel socioeconómico de Ciudad Juárez, Chihuahua, México. MÉTODOS: Se utilizó el enfoque de comunicación de riesgos de los modelos mentales para identificar importantes brechas en la comprensión pública. Este enfoque consiste en la evaluación paso a paso de las necesidades de información y la eficacia de los esfuerzos de comunicación de riesgos, mediante entrevistas y encuestas. RESULTADOS: El proceso basado en los modelos mentales descubrió un malentendido técnico clave: la población estudiada cree que el monóxido de carbono se puede ver u oler. Esto puede llevar a un comportamiento proclive al riesgo: no utilizar detectores de monóxido de carbono. Se diseñó un protocolo de comunicación para atender esta y otras brechas en el conocimiento que, según las evaluaciones previa y posterior, mejoró significativamente el nivel de conocimiento de las personas. CONCLUSIONES: El proceso basado en modelos mentales permitió desarrollar exitosamente un instrumento de comunicación capaz de mejorar el nivel de conocimiento en la población estudiada. Investigaciones futuras deben evaluar en qué grado este instrumento logra modificar el comportamiento y reducir el riesgo de intoxicación por monóxido de carbono. Nuevas intervenciones podrían centrarse en estimular el uso de detectores de monóxido de carbono.