When the month of October 1918 ended, the families of the municipality of Calpulalpan, Tlaxcala, began to suffer the fatal consequences of the flu or Spanish influenza pandemic. Although in the macro scenario the expectations for the public health problem were discouraging, what is remarkable is that at the end of the epidemic cycle in the municipality of Tlaxcala, the mortality rate was barely 2.93. Although the global figure was not so impressive, when looking inside the towns, haciendas and ranches, a different reality is confirmed by the fact that the maximum mortality was 6.12, the minimum 0.16 and even most farms did not contribute to any deaths. This heterogeneity shows that the high figures were determined by the lack of knowledge of the danger of the disease and, otherwise, by adherence to following certain prophylaxis standards. Whether it was one case or the other, the spread of contagion and the magnitude of mortality are argued showing the results by sex and age, collective and individual deaths within families, preventive hygiene recommendations issued by government authorities and the population mobility as a factor of incidence in the entry and spread of the virus.