Dengue occurrence relations and serology: cross-sectional analysis of results from the Guerrero State, Mexico, baseline for a cluster-randomised controlled trial of community mobilisation for dengue prevention.

BACKGROUND: The Mexican arm of the Camino Verde trial of community mobilisation for dengue prevention covered three coastal regions of Guerrero state: Acapulco, Costa Grande and Costa Chica. A baseline cross-sectional survey provided data for community mobilisation and for adapting the intervention design to concrete conditions in the intervention areas. METHODS: Trained field teams constructed community profiles in randomly selected clusters, based on observation and key informant interviews. In each household they carried out an entomological inspection of water containers, collected information on socio-demographic variables and cases of dengue illness among household members in the last year, and gathered paired saliva samples from children aged 3-9 years, which were subjected to ELISA testing to detect recent dengue infection. We examined associations with dengue illness and recent dengue infection in bivariate and then multivariate analysis. RESULTS: In 70/90 clusters, key informants were unable to identify any organized community groups. Some 1.9% (1029/55,723) of the household population reported dengue illness in the past year, with a higher rate in Acapulco region. Among children 3-9 years old, 6.1% (392/6382) had serological evidence of recent dengue infection. In all three regions, household use of anti-mosquito products, household heads working, and households having less than 5 members were associated with self-reported dengue illness. In Acapulco region, people aged less than 25 years, those with a more educated household head and those from urban sites were also more likely to report dengue illness, while in Costa Chica and Costa Grande, females were more likely to report dengue illness. Among children aged 3-9 years, those aged 3-4 years and those living in Acapulco were more likely to have evidence of recent dengue infection. CONCLUSIONS: The evidence from the baseline survey provided important support for the design and implementation of the trial intervention. The weakness of community leadership and the relatively low rates of self-reported dengue illness were challenges that the Mexican intervention team had to overcome. The higher dengue illness occurrence among women in Costa Grande and Costa Chica may help explain why women participated more than men in activities during the Camino Verde trial.

Variability of mercury in urine among Mexican women residing in a mining area.

OBJECTIVE: To know the variability of the creatinine-adjusted inorganic mercury (HgUCr) levels in women aged >or=12 years to evaluate the impact of residing at a site contaminated by mercury in soil. METHODS: A cross-sectional epidemiologic study was conducted, in which 122 women participated, in whom, HgUCr was determined. Simultaneously, a questionnaire was applied for evaluate the different factors of mercury exposure, sociodemographic characteristics, and dietary hygiene measures. The environmental exposures were evaluated by measure Hg in soil and mining dumps. RESULTS: Women aged >30 years residing in areas contaminated by Hg in soil (>625 ppb) had 212% more HgUCr than the women who living in areas least contaminated, while women with amalgam dental fillings had 120% more HgUCr than women without these. CONCLUSION: In conclusion, exposure to different physicochemical forms of Hg by environmental mechanisms and factors intrinsic to the women are probably responsible for HgUCr-level variability in the women.