Mexico

Background and previous studies in Acapulco and the Guerrero Coasts

In Mexico, dengue fever cases multiplied from 5,018 reported in 2003, to 48,456 in 2007, an almost ten-fold increase. At the same time, the vector mosquito has begun entering states where it was not present before, and in those where it used to be found only in urban areas it can now be found in rural ones as well. This is why the National Health Secretariat considers the disease a national security issue.

Guerrero State, located on Mexico’s southern Pacific coast, has the second-highest dengue hemorrhagic fever rate in the country (35/100 000), with all four varieties or serotypes of the disease present. During the last widespread epidemic in 2006, a special ward was opened in the Acapulco hospital for cases of dengue hemorrhagic fever. Guerrero, whose population exceeds 3 million inhabitants, is one of Mexico’s poorest states. Acapulco and Zihuatanejo are large tourist destinations on the coast, where dengue is endemic. Tourists return from this area to every part of Mexico, the United States and Canada.

The Government of Guerrero’s strategy to control the vector mosquito —Aedes aegypti— relies largely on depositing a packet of the organophosphate temephos in household water containers every three months. Mexico’s laws allow for this to be done without consent from the heads of the households, even though temephos has not been approved for human consumption in the United States, where it is produced. Studies that have not been financed by the industry have documented a sub-lethal animal toxicity and the potential for causing genetic damage. The mosquito’s resistance to temephos is well documented.

CIET studies in Guerrero

CIET has carried out studies on this topic in communities along the Pacific coast of Guerrero State since 1988. That year, research about malaria and dengue showed that, in spite of thinking they had a clear idea about the mosquitoes that carry these diseases, people from the communities did not know that the mosquitoes come from larvae whose numbers can be controlled by getting rid of breeding sites.

In 2004, CIET conducted a survey in 13 residential clusters of Acapulco, in order to measure dengue-related knowledge, attitudes and practices. The survey covered 1,412 households and 6,678 residents. Besides administering a household questionnaire, the survey teams inspected potential Aedes aegypti breeding sites. Most survey participants had some dengue-related knowledge, such as the mosquito’s role in spreading it and its reproductive habits, but less than a third of participants had the necessary knowledge to adequately deal with the problem. The greatest factor in sites where the inspections detected the presence of Aedes aegypti larvae was the lack of adequate covering for water storage containers. Only one home in four had properly covered its water containers.

With support from CIET staff, a graduate student carried out a survey of children in 24 primary and 12 secondary schools in Acapulco, to assess their knowledge about dengue and how to control it. Only 11% had adequate knowledge about the disease and 8% understood how it is transmitted. But the children’s and youths’ willingness to participate in efforts to control the mosquito’s reproduction within their households was very high. The study showed clearly that, with adequate education about the disease and how to prevent it, these youth could be an important resource to replace the hierarchical structure that prevails in efforts to control dengue through community- and household-based actions.

These research projects, along with a CIET pilot project for dengue control rooted in evidence-based community participation in Managua, Nicaragua (2004-2007), laid the groundwork for developing the Camino Verde experience in Mexico.