Study Projects

Climate Variability and Human Health Impacts in Mexico

Research Results – 2003/01
Research Results – 2002/09

Funding Institution

Inter-American Institute for Global Change Research
http://www.iai.int

Project Summary

Research Objectives

To analyze the association between malaria incidence and climate in Mexico, focusing on seasonal to interannual climatic variability due to El Niño/Southern Oscillation.

To analyze the association between dengue incidence and climate in Mexico, focusing on seasonal to interannual climatic variability due to El Niño/Southern Oscillation.

Geographic Areas

The study sites for malaria are the 15 Mexican states (about half of the Mexican states) with the most malaria cases in 1986-2000. Three states are selected for detailed study based on five criteria for malaria incidence and social exclusion (marginality) -- Oaxaca, Chiapas and Sinaloa. Municipalities inside these states are selected based on the same five criteria for malaria incidence and social exclusion,  contrasting ecological regions (coast and mountain) and contrasting malaria vector species.

The study sites for dengue are the 15 Mexican states with the most dengue cases in 1986-2000. Three states are selected for detailed study based on criteria for dengue incidence and social exclusion -- Tamaulipas, Veracrúz and Colima (probable). Municipalities inside these states are selected based on criteria for dengue incidence and social exclusion used in selecting states; contrasting ecological regions (coast and mountain); contrasting dengue vector species.

Data Collection - Retrospective/Prospective

These retrospective studies use several sources of data:
  • Cases of malaria and dengue at state and municipality levels from the Secretariat of Health for 1980-2000.
  • National census data at the levels of county and geostatistical area (AGEB) from the National Institute of Geography and Statistics for 1970, 1980, 1990 and 1995.
  • Social exclusion (marginality) index based on multiple social variables at the levels of states and municipalities from the National Council of Population. The social variables include income, education, household, and water and drainage availability during the 1990s.
  • Urbanization and migration attraction rates at the levels of states and municipalities from the National Council of Population.
  • Socio-demographic aspects (age, sex, rurality) and socio-economic data at the level of geostatistical area (AGEB) from the National Institute of Geography and Statistics.
  • Death certificate data at the municipal level from the National Institute of Geography and Statistics for 1982-2002.
  • Output from climatological forecasting models from the Centro de Ciencias de la Atmósfera (National Autonomous University of Mexico).
  • Rainfall, humidity and temperature data from the Servicio Meteorológico Nacional, part of the Comision Nacional del Agua, Secretariat for Environment continuously for 1940 to the present.
  • UV monitoring stations (for two years in three cities) and forest cover trends from the project on the National Inventory of Global Warming Gases of the National Institute of Ecology for 1990 to 1997.
  • Entomological data from malaria-endemic areas from historical projects.

Methodology

The effort involves four main scientific tasks:

  • Collection and validation of time series data.
  • Analysis of the relationships among time series data for epidemiological, climatological, vector behavioral and social variables with stratification by ecological area.
  • Display of data relationships on a geographic information system (GIS).
  • Linkage of time series analysis with climate forecasting models.
Research Team

The leader of the research team is Dr. Horacio Riojas-Rodriguez, an epidemiologist at the Instituto de Salud, Ambiente y Trabajo (ISAT) in Mexico City, Mexico. He supervises Mario Caballero Ramirez, who is a doctoral student at the National Autonomous University of Mexico (UNAM). He also supervises a masters-level student in the biological sciences at UNAM. He works in collaboration with Dr. Carlos Gay Garcia of the Centro de Ciencias de la Atmósfera (UNAM).

References
Downs T. et al. 1998. DDT- Alternative Management project in Oaxaca and Chiapas States of México. Technical Report for the Secretariat of Health and the Commission on Environmental Cooperation of North America.

Gallardo Díaz E. et al. 2000. Situación de la malaria y el uso del DDT en México. Informe de país para el Proyecto "Programa de acción integral para eliminar progresivamente el DDT y reducir los efectos a largo plazo de la exposición al mismo en México y América Central", Centro Nacional de Salud Ambiental, Centro de vigilancia Epidemiológica, Secretaría de Salud, México.

Gomez-Dantes H, Ramos-Bonifaz B, Tapia-Conyer R. 1995. The risk of dengue transmission: a space for stratification. Salud Publica Mex 37 Suppl:S88-97.

Magaña Rueda Victor O., (editor). 1999. Los impactos de El Niño en México. Centro de Ciencias de la Atmósfera UNAM, México, con apoyo de la
Dirección General de protección civil, Secretaría de Gobernación, México.

Santos-Burgoa C, Caballero RM. 2000. Diagnóstico situacional del uso del DDT y el control de la malaria en México y Centroamérica. Guía de
trabajo. Consultoría para la Comisión para la Cooperación Ambiental, representación en México.

Velasco E et al (Binational health data transfer task force CDC/SSa). 1996. "Binational health care for migrants". In: Children of the Border , ERIC Clearinghouse of Rural Education. USA. pp 183-201.