ABSTRACT
Arsenic exposure in adults has been associated with increased serum matrix metalloproteinase-9 (MMP-9), a biomarker which is associated with chronic respiratory disease, lung inflammation, cardiovascular disease and cancer. The objective of this study was to evaluate the association between serum MMP-9 levels in children, urinary arsenic, arsenic chronic daily intake (CDI) and arsenic exposure from playground dust. This cross-sectional study examined 127 children from five elementary schools, in Hermosillo, Sonora, Mexico. Arsenic was analyzed in the dust using a portable X-ray fluorescence (XRF) analyzer. Total urinary arsenic was determined by inductively coupled plasma/optical emission spectrometry. Serum was analyzed for MMP-9 using ELISA. Arsenic levels in playground dust averaged 16.9 ± 4.6 mg/kg. Urinary arsenic averaged 34.9 ± 17.1 µg/L. Arsenic concentration in playground dust was positively associated with serum MMP-9 levels in crude analyses and after adjustment (P < 0.01), MMP-9 and CDI were positively associated only after adjustment (P < 0.01), and no association was found between MMP-9 and urinary arsenic. In conclusion, our study showed an association in children between serum MMP-9 levels and playground dust arsenic concentrations. Therefore, exposure to arsenic in dust where children spend significant time may manifest toxic effects.
Subject(s)
Arsenic/toxicity , Dust , Environmental Biomarkers , Environmental Pollutants/toxicity , Matrix Metalloproteinase 9/blood , Adolescent , Arsenic/urine , Child , Child, Preschool , Cross-Sectional Studies , Dust/analysis , Environmental Exposure/analysis , Environmental Pollutants/urine , Female , Humans , Male , Mexico , SchoolsABSTRACT
Cryptosporidium and Giardia are gastrointestinal disease-causing organisms transmitted by the fecal-oral route, zoonotic and prevalent in all socioeconomic segments with greater emphasis in rural communities. The goal of this study was to assess the risk of cryptosporidiosis and giardiasis of Potam dwellers consuming drinking water from communal well water. To achieve the goal, quantitative microbial risk assessment (QMRA) was carried out as follows: (a) identification of Cryptosporidium oocysts and Giardia cysts in well water samples by information collection rule method, (b) assessment of exposure to healthy Potam residents, (c) dose-response modelling, and (d) risk characterization using an exponential model. All well water samples tested were positive for Cryptosporidium and Giardia. The QMRA results indicate a mean of annual risks of 99:100 (0.99) for cryptosporidiosis and 1:1 (1.0) for giardiasis. The outcome of the present study may drive decision-makers to establish an educational and treatment program to reduce the incidence of parasite-borne intestinal infection in the Potam community, and to conduct risk analysis programs in other similar rural communities in Mexico.
Subject(s)
Cryptosporidiosis/epidemiology , Cryptosporidium/isolation & purification , Giardia/isolation & purification , Giardiasis/epidemiology , Groundwater/microbiology , Cryptosporidiosis/microbiology , Giardiasis/microbiology , Humans , Indians, North American , Mexico/epidemiology , Risk Assessment , Water WellsABSTRACT
BACKGROUND: Cryptosporidium oocysts and Giardia cysts can be transmitted by the fecal-oral route and may cause gastrointestinal parasitic zoonoses. These zoonoses are common in rural zones due to the parasites being harbored in fecally contaminated soil. This study assessed the risk of illness (giardiasis and cryptosporidiosis) from inhaling and/or ingesting soil and/or airborne dust in Potam, Mexico. METHODS: To assess the risk of infection, Quantitative Microbial Risk Assessment (QMRA) was employed, with the following steps: (1) hazard identification, (2) hazard exposure, (3) dose-response, and (4) risk characterization. RESULTS: Cryptosporidium oocysts and Giardia cysts were observed in 52% and 57%, respectively, of total soil samples (n=21), and in 60% and 80%, respectively, of air samples (n=12). The calculated annual risks were higher than 9.9 × 10(-1) for both parasites in both types of sample. CONCLUSIONS: Soil and air inhalation and/or ingestion are important vehicles for these parasites. To our knowledge, the results obtained in the present study represent the first QMRAs for cryptosporidiosis and giardiasis due to soil and air inhalation/ingestion in Mexico. In addition, this is the first evidence of the microbial air quality around these parasites in rural zones.
