Peromyscus mexicanus from San Cristóbal de Las Casas, Chiapas.

Rodents are strongly linked to environmental conditions, and in this constantly changing world, preserving natural areas is important. In this context dilution effect postulates that natural and preserved areas support high diversities of inefficient reservoir species and, contribute to dilute pathogenicity of the efficient reservoirs. Whilst, non-preserved areas as urbanizations, pasturelands and croplands, support higher diversities or rodent reservoirs.

In the Mexican state of Chiapas, the eradication of natural vegetation is devastating: 50 % of original vegetation has been eliminated and transformed into rural areas, croplands and pasturelands. Additionally, more than half the population state is living in poverty conditions and in rural localities, exposing themselves to enter in contact with wild fauna, specifically with rodents. Humans and rodents are using the same habitat and, therefore, some rodent species are being displaced.

Understanding the role of urbanization process over rodent species diversity, species turnover and presence of rodent reservoirs of zoonotic viruses, like Mammarenavirus (associated to hemorrhagic fevers in humans) in small localities in Chiapas, it will allow us to suggest the importance of preserving natural areas. The diversity of rodents could be higher in natural areas than in transformed ones, and the prevalence of Mammarenavirus could be lower.

The specific project goals are: 1) establish the rate of change of natural areas into urban areas in a lapse time of 30 years (1990 to 2020); 2) assess diversity of rodent species in an urban gradient; 3) identify potential epidemiologic risk areas according to suitability conditions for rodent species and, 4) evaluate Mammarenavirus prevalence in rodent populations.