Dinámica de zonas climaticas y su relación con la distribución potencial del aedes aegypti

Abstract

Nowadays, one of the most important diseases worldwide in the health sector is dengue. This virus is transmitted mainly by the vector Ae. aegypti that is easily distributed in Mexico because the tropical climates of the territory favor its transmission. According to compiled records by official institutions, the presence of cases of Dengue Fever (DF) has increased in recent years in the Mexican Central Plateau, despite unfavorable conditions for the development of the infectious agent in comparison with coastal regions where it exists endemically. The present research work modeled the potential distribution of the transmitter vector under its environmental characterization of ecological niche to identify and analyze the vulnerable areas to the dengue transmission, which was carried out in 5 stages that are: 1) Review and search of literature on the general characteristics of the vector Ae. aegypti. As a stage; 2) dengue case data were collected, records of species Ae. aegypti and climate data for the central part of Mexico, to know the relationship of cases with the dynamics of climatic areas. 3) the data of the species Ae . aegypti and cases of dengue was processed and structured. 4) Generation of a potential distribution model based on the maximum entropy method (MaxEnt) to identify the probable risk areas in the presence and distribution of the virus and 5) Continuity was given to the model projecting under climatic scenarios and thus knowing the possible dynamics of the mosquito transmission area. As results, the climatic conditions that are determining in the presence of cases were identified. The initial modeling was performed with records of the presence of species and a set of 23 environmental variables, however, the number of explanatory variables was reduced, according to their contribution and correlation analysis, allowing the generation of a final model with 5 variables (minimum temperature of the colder month | Bio6 |, precipitation of the wettest month | Bio13 |, seasonal precipitation | Bio15 |, NDVI and relative humidity) which explained about 90% contribution to the model. DF rates were generated for the study period (2009 to 2015), in order to evaluate the association based on the OR indicator (odds ratio) for each suitability category. Category 1 was considered as an unpredicted area and corresponded to a protection zone (OR <1) because it was not associated with FD rates and, according to the criteria considered, possible imported cases are suspected. Regarding category 2 to 4, they are the areas of suitability and have values of OR> 1, in which category 4 was identified as the area of greatest risk to transmission with the highest OR of 71.53 (p <0.001) for being a region of lower elevation and presenting a warm climate. The projections made revealed that each of the models considered in this work shows a variation in the possible risk areas; agreeing that the focus of transmission is in the state of Morelos, Puebla and south of the State of Mexico, with portions in the center, northwest and southwest of the study area. The scenarios indicate that if these changes occur, the Valley of Mexico can be affected, where a high population density is identified. The changes in the areas do not show an increase in risk areas but a displacement in places where the vector did not appear before, so it is very likely that the population is not prepared for the presence of the disease.