Background: Increase of climatic variability is influencing the behavior of influenza that causes acute respiratory infections.
Objective: To determine the mechanisms of influenza response to climate variability.
Methods: An ecological study with retrospective analysis of time series of Influenza and climatic, combined with the techniques of exploratory data analysis and correlation analysis with and without delay was performed. Influenza data (2010-2017) and climatic anomalies described by the Bultó climatic indexes were considered. For trend the Spearman and Kendall-Mannt coefficients were used. Cluster analysis of months and regions of Influenza was used. Kriging method combined with the inverse distance at 20 km2 and weight matrix by the "queen" method of second order of contiguity was used, the spatial autocorrelation by the Moran's I, the Moran's correlograms and the Local Space Association Indicators were calculated.
Results: Influenza shows a circulation increase in the months of rainy season (May-October) with cycles of 2 years and a clear association with the climate variability. High humidity, temperature and precipitation predominated Influenza has a global tendency to decrease with a high persistence or serial correlation. It reaches a value of the Mann Statistician, 2.012 (0.0001) in the year 2010, however it decreases in time. Cumulative effect up to 2 months of the climate in the Influenza, with a correlation of 0.30 (p<0.0043) and 0.35 (p<0.00051) was evidenced. With a strong spatial correlation (Moran's I˃0.4136 during July), the central region showed the higher circulation.
Conclusions: Influenza responds to climatic variability mainly during the rainy season (May-October), period in which high humidity, temperature combined with low pressures favor the viral circulation, condition the pH in the respiratory tract, leading to additional acidification of the local areas of the respiratory system.