Pulmonary Tuberculosis seasonality in Tunisia

<b>Introduction:</b> Determining the temporal variationts and seasonal pattern of disease can help in promoting disease control and management program. Although seasonal variation in pulmonary tuberculosis (PTB) incidence has been described in many countries, it remains unknown in Tunisia. The objective of the study is to determinate seasonal variability of PTB in Tunisia. <b>Methods:</b> A time series study was conducted including pulmonary tuberculosis cases diagnosed in pulmonary departement of Rabta hospital from Junuary 2017 to December 2019. The aggregated number of monthly and seasonal PTB cases was obtained by adding the daily counts. We obtained also data of mean daily temperature from the Tunisian Meteoreological Agency. <b>Results:</b> A total of 200 cases of active PTB were reported, seventy nine percent of the patients were male. the seasons with the highest number of cases were spring (32%) and winter (24%) with significant difference (p&lt;0,05). The highest number of case was registered in April, May and March with respectively 13%; 11%; 8% cases. There was no difference in season amplitude between males and females. Old people (&gt;65 years) are more affected by seasonality (39.2% in winter). <b>Conclusion:</b> PTB is a seasonal disease in Tunisia. We can suggest several factors responsible for this seasonal variation such as environmental factors, respiratory infections, characteristics of the Tunisian climate and also living in confined spaces in winter.