Tuberculosis is a disease caused by a Mycobacterium tuberculosis complex, the most common of which is Mycobacterium tuberculosis or Koch’s bacillus [1] . In 1882, Robert Koch isolated the tuberculosis bacillus for the first time [2] . The causative agent of tuberculosis is thought to have two different evolutionary lineages, the first of which affects only humans [3] . The second lineage, which is thought to be of animal origin, also infects humans but mainly affects mammals such as cattle, goats, and rodents. Transmission of tuberculosis is primarily through the air for the first lineage and through food for the second lineage. Tuberculosis can manifest itself clinically as pulmonary tuberculosis and extrapulmonary tuberculosis. Extrapulmonary tuberculosis affects other organs in the body, in addition to the lungs. Tuberculosis remains a major public health problem, with a high incidence worldwide and in sub-Saharan Africa. Over the last decade, there has been an increase in the number of cases of tuberculosis worldwide, with variations depending on the region and the population. The reported global number of people newly diagnosed with TB was 7.5 million in 2022. This is the highest number since the WHO began monitoring tuberculosis on a global scale [1] . Burkina Faso is a West African country with a National Tuberculosis Control Program and a health information system that appear to be similar to those in other sub-Saharan African countries. In order to detect, treat, and prevent tuberculosis in as many people as possible, a better control strategy is needed. A better control strategy requires the development of better diagnostic techniques. Initially, tuberculosis was diagnosed by culture before the development of more specific techniques, particularly molecular techniques. The country has seen a resurgence in new cases of tuberculosis in recent years despite the implementation of strategies to combat and prevent the disease [4] . Given this situation, it would be useful to have an overview of changes in prevalence and diagnostic methods in recent years. The aim of this study was, therefore, to estimate the prevalence of tuberculosis in Burkina Faso over the last 10 years and to summarize the diagnostic methods used.

This study assessed the available data on the prevalence of tuberculosis and the diagnostic methods used over the last 10 years in Burkina Faso. The overall prevalence of all types of patients combined was 31.58% among the studies considered. When we look at the data for the years targeted by the study, we find a prevalence of 49.2% for 2014 reported at the Sourô Sanou University Hospital (CHUSS) in Bobo-Dioulasso [10] then a value of 44.1% at collection sites such as the district of Bogodogo and the Saint Camille medical centre in Ouagadougou [11] . Sanogo et al. carried out their sample collection from 2012 to 2014, compared with the authors of the Ouagadougou study, for whom the study only covered 2014. This could explain the higher prevalence found by the first authors cited. Two other studies, whose sample collection period included 2014 found lower prevalence rates of 26% [12] and 15% [13] , respectively. These values could be due to the short sample collection period (3 months) for the study by Ouedraogo et al. Regarding the study by Marcy et al. in 2016, the patients recruited were children under 13 years of age living with HIV. In 2015, the prevalence mentioned by the data found was 1.48% [14] . This low prevalence could be explained by the fact that the authors had looked for Mycobacterium tuberculosis in suspected cases of meningitis rather than tuberculosis, but also by the type of sample used (Cerebrospinal fluid). From January to July 2016, a prevalence of 23.6% was observed in patients suspected of having tuberculosis [6] . This value is comparable to the prevalence of 26.8% obtained by authors in Ethiopia among the same types of participants who were suspected of having tuberculosis [15] . In 2020, the tuberculosis prevalence rate obtained by Djibougou and colleagues was 63.36% [7] . This high prevalence came from case contact patients in whom latent tuberculosis had been detected by Tuberculin skin test (TST) and Interferon Gamma Release Assays (IGRAs). Authors have found a lower prevalence among contact cases of 38.10% and 43.6% respectively in Indonesia among children under 5 years of age [16] and India in older participants [17] .

In parallel with these prevalence values obtained by the various studies, from 2014 to 2023, tuberculosis is notified each year in Burkina Faso in terms of the number of cases. In 2014, the number of tuberculosis cases was 5792; in 2015, it had risen to 5808. Between 2016 and 2020, the number of tuberculosis cases rose from 5918 to 6207. The number of tuberculosis cases fluctuated, reaching 7619 in 2021, 7320 in 2022 and 8613 in 2023. National data for 2024 are not yet available. In 2023, the number of new cases and relapses was 8613, compared with 7320 in 2022, an increase of 17.7%. One reason for this is the application of directives, the implementation by the Burkinabe government of the Active case-finding (ACF), and the increase in the number of GeneXpert devices in health centers across the country [4] .

In Burkina Faso, tuberculosis is a notifiable disease that can be diagnosed using various types of samples. In the analyzed studies, some authors used conventional samples for the detection of Mycobacterium tuberculosis, such as sputum, gastric tubes, blood, etc. [7] . Other authors have explored alternatives such as the use of stools, nasopharyngeal swabs, and cerebrospinal fluid. While the study by Ouedraogo et al. in 2016 found that stools were less contributory than sputum, probably due to the pre-treatment stage; in the study by Sanogo and colleagues, the comparison between the two types of samples gave the same detection rate [10] . These alternative samples would, therefore, detect Mycobacterium tuberculosis just as well as standard samples and could be used for children, in whom it is often complicated to obtain a good sputum [18] .

Tuberculosis can be diagnosed clinically and bacteriologically. Bacteriological diagnosis is made from sputum samples and other biological fluids such as gastric tube fluid, ascites puncture, and pleural puncture. [19] . Clinical diagnosis is made on the basis of clinical signs and additional examinations such as the X-ray used in the study of Berteloot et al. [20] .

A review of the different methods used by authors in studies from 2014 to the present day for the bacteriological diagnosis of tuberculosis showed that the use of microscopy and molecular techniques ranked equally at over 70% compared with less than 30% for culture. For a long time, microscopy and culture were the only techniques used before the introduction of GeneXpert in 2013 in Burkina Faso [21] . The use of microscopy was common to all authors [6] [11] [12] [22] [23] followed by culture [8] [10] [12] and Tuberculin Skin Test (TST) [24] . Gene amplification techniques were also mentioned [11] [14] , including GeneXpert [6] [9] [13] [23] as well as QuantiFERON^®-TB Gold test [23] [24] and Vidas TB-IGRA which are automated methods for quantifying gamma interferon compared with the classic Elisa method [25] . Although microscopy remains the standard, recent tests have made a significant contribution to the diagnosis of tuberculosis in Burkina Faso.

The results of this study show that there is heterogeneity in the reported prevalence of tuberculosis in Burkina Faso. There are very few studies on the subject, probably due to the fact that there is a national tuberculosis control program that compiles information on cases and publishes an annual report on incidence. There has been a downward trend in the number of cases reported over the years. As for diagnostic methods, the last 10 years have seen the introduction of more specific molecular techniques, as well as the use of alternative samples to sputum for the detection of Mycobacterium tuberculosis. The Burkinabè health system needed to step up its prevention efforts through awareness campaigns and mass screening using the new diagnostic methods, and by providing all screening centres with GeneXpert equipment.

The authors would like to thank Mr. Jean LOMPO for his assistance with English-language editing.