The influence of temperature and rainfall in the human viral infections

It is well described by many authors the occurrence of viruses outbreaks that occurs annually at the same time. Epidemiological studies could generate important information about seasonality and its relation to outbreaks, population fluctuations, geographical variations, seasonal environmental. The purpose of this study was to show the influence of temperature and rainfall on the main viral diseases responsible for high rates of morbidity and mortality. Data were collected from samples performed at the Virology Laboratory of the Hospital de Clinicas da Universidade Federal do Parana (HC-UFPR), which is a university tertiary hospital, in the period of 2003 to 2013. The temperature (°C) and mean monthly rainfall (mm) data was provided by the Sistema Meteorologico do Parana (SIMEPAR-PR). The study of viral respiratory infection has revealed an incidence and pattern of seasonal prevalence of the respiratory viruses in Curitiba city, Southern Brazil. It was observed that in the months when the temperatures were lower, especially during June and July, there were an increasing number of samples collected as well as positive scores. For Rotavirus infections it was observed an increase in positive cases was observed in certain years, particularly during the colder months. Enteroviruses circulated in higher frequency during summer months with a median temperature of 21.5°C. Herpesviruses were distributed along the year but its circulation was not observed during the winter months. In conclusion it was observed the seasonality pattern of the viruses’ circulation in Curitiba city, on the other hand rainfall did not demonstrated the same pattern.