Research Article: Epidemiology and disease burden of tuberculosis in south of Tunisia over a 22-year period: Current trends and future projections

Date Published: July 24, 2019

Publisher: Public Library of Science

Author(s): Houda Ben Ayed, Makram Koubaa, Lamia Gargouri, Maissa Ben Jemaa, Maroua Trigui, Fatma Hammemi, Mariem Ben Hmida, Abdelmajid Mahfoudh, Neila Zalila, Aida Mustapha, Chokri Masmoudi, Chakib Marrakchi, Sourour Yaich, Feriel Messaadi, Ali Ayedi, Jamel Damak, Mounir Ben Jemaa, Kingsley Nnanna Ukwaja.


Tuberculosis (TB) is a public health problem worldwide. Characterizing its trends over time is a useful tool for decision-makers to assess the efficiency of TB control programs. We aimed to give an update on the current chronological trends of TB in Southern Tunisia from 1995 to 2016 and to estimate future trajectories of TB epidemic by 2030.

We retrospectively collected data of all notified TB new cases by the Center of Tuberculosis Control between 1995 and 2016 in South of Tunisia. Joinpoint Regression Analysis was performed to analyze chronological trends and annual percentage changes (APC) were estimated.

In the past 22 years, a total of 2771 cases of TB were notified in Southern Tunisia. The annual incidence rate of TB was 13.91/100,000 population/year. There was a rise in all forms of TB incidence (APC = 1.63) and in extrapulmonary tuberculosis (EPTB) (APC = 2.04). The incidence of TB increased in children and adult females between 1995 and 2016 (APC = 4.48 and 2.37, respectively). The annual number of TB declined in urban districts between 2004 and 2016 (APC = -2.85). Lymph node TB cases increased (APC = 4.58), while annual number of urogenital TB decreased between 1995 and 2016 (APC = -3.38). Projected incidence rates would increase to 18.13 and 11.8/100,000 population in 2030 for global TB and EPTB, respectively.

Our study highlighted a rise in all forms of TB and among high-risk groups, notably children, females and lymph node TB patients in the last two decades and up to the next one.

Partial Text

Tuberculosis (TB) is a global pandemic which poses a serious threat to public health throughout the world [1]. Despite effective treatment, TB is the leading cause of death from a single infectious agent, ranking above Human Immunodeficiency Virus (HIV), excluding HIV-TB co-infection [2]. TB is a bacterial infection caused by different types of mycobacterium, notably Mycobacterium tuberculosis and Mycobacterium bovis. It may occur at different anatomical sites of the human body, affecting lung parenchyma, called pulmonary tuberculosis (PTB) or other anatomical sites outside parenchyma, designated extra-pulmonary tuberculosis (EPTB). According to the global tuberculosis report of 2018, 10 million people fell ill with TB and there were an estimated 1.3 million TB deaths in 2017 worldwide [2]. In regard to global burden of disease, TB is predicted to maintain its status up to 2020 [3], despite international attention paid to the disease and effective prevention and control programs. The WHO has developed the End Tuberculosis Strategy, with a goal of 90% reduction in incidence and 95% reduction in mortality by 2035 [4]. In Tunisia, TB is of a public health concern. In 2014, there were 3170 new TB cases of any form, among which 59% were EPTB cases [5]. The notification rate of TB, all forms combined, was 28.8/ 100,000 population and the mortality rate was 2/100,000 population in the same year [5,6]. National Tuberculosis Control Program was implemented in Tunisia since 1959, which primary aim was to significantly reduce the burden of TB in compliance with the Sustainable Development Goals, which primary aim was to end TB related deaths, transmission and catastrophic costs by 2030 [7]. The highest rates were recorded in Southern Tunisia, where tuberculosis management is still challenging. Evidently, apart from economic losses, TB burden had an adverse impact either on patients’ quality of life or on their family members. Description of the epidemiological profile of the disease over time and characterizing its chronological trends could play an important role to assess the performance of control strategies for different periods, health development indicators and health planning. Since TB does not homogeneously affect the population, selected high-risk groups and studying their current and future trends should be identified in all settings as they deserve special attention and should be addressed specifically with additional interventions. Moreover, it is a useful tool for health-care professionals and decision-makers to improve planning policies attributed to TB and prioritization as well as the efficacy and efficiency of health program planning. In light of the challenging epidemiological situation and the lack of reliable and recent TB data, we sought to give an update about the current chronological trends of TB from 1995 to 2016 and to predict future trajectories of the TB epidemic up to 2030 in South of Tunisia.

Using TB surveillance data of 2771 patients, we conducted the first assessment of TB burden in South of Tunisia, overall and within subpopulations of different socio-demographic characteristics in the last two decades. This study reported that all TB forms incidence rate as well as EPTB had significantly increased in the last two decades and will continue to rise in the next 10 years. This alarming upward trend was illustrated particularly among high-risk groups, including children, females, and rural districts residents.

Our study provided an insight into the magnitude of TB in Southern Tunisia. TB incidence was higher among the productive age group. Significant increase in the trend of TB globally and among high-risk groups, notably children, females, and rural districts residents in the last two decades and up to the next one, is a point of concern highlighting the importance of strengthening health care services towards these groups. Lymph node TB was epidemic in our region, suggesting the urgent need to establish preventive strategies for controlling zoonotic tuberculosis transmission. These findings provided useful measurements to health-decision makers to better evaluate the efficiency of TB program in our country and to prioritize curative and preventive interventions accordingly.




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