Surveillance of the Buruli Ulcer in The Democratic Republic of Congo (Drc): Preliminary Results (2016-2018)

Context: Buruli ulcer poses a real public health problem, not well known, calling for international mobilization. It is an emerging threat to public health in many rural and inter-tropical regions, and DRC is not immune to this problem. However, improving the visibility of this disease and mobilizing resources are ways to make disease control activities more effective. Objective: To gather information on Buruli ulcer in the different provinces of the DRC. Material and methods: Samples came from different provinces of DRC from patients uspected of Buruli ulcer. Two techniques were performed namely Ziehl-Nelsen and real-time PCR to confirm cases. Data comparison was performed using the Chi-square test. Results: During 3 years of surveillance (2016-2018), 984 samples were recorded, of which 86.1% were swabs. 72 (7.3%) were Ziehl positive and 251 (25.51%) were confirmed by PCR-(p <0.001). However, the positivity by province, led by Equateur (11/19, 57.9%), followed by Kongo Central (215/707, 30.4%) and Maniema (16/52, 30, 7%). On the other hand Haut Uele and Kinshasa had respectively 3/13(23, 1%) and 13/188(6, 9%). Conclusion: Buruli ulcer surveillance is a public health goal both to measure the importance and trends of its incidence in DRC. This monitoring is important for better documenting the burden of the disease, mapping endemic villages and also ensuring better case management.


Introduction
Central Province [4][5][6][7]. Thus, early diagnosis and treatment are the only means to minimize morbidity and avoid long-term disability [1][2][3]. It is within this framework that the National Institute for Biomedical Research (INRB) has set up a surveillance system for the confirmation of cases by molecular test.

Objective
To confirm cases and document Buruli ulcer in the different provinces of DRC.

Sources and Methods
INRB relies on the various health zones of DRC to carry out surveillance of BU.

Data Processing
The data were recorded in the laboratory register and then transferred to the Excel software. Data comparison was done using the Chi-square test and the significance level was set at 5% and the 95% confidence interval (CI). 43.9% of the samples were from female patients, 50.6% from male, and for 5.5% of patients (p = 0.002) gender was not determined.

Results
The sex ratio was 1.2. The average age of patients was 36.75 years with extremes ranging from 1 month to 89 years. The distribution by age group is shown in (Figure 1).

Discussion
Surveillance of BU is of paramount importance, as people affected with the disease can end up with more or less significant disabilities for life [1][2][3][4][5][6][7][8][9][10]. And so, confirmation of cases by molecular testing appears both as a necessity and a priority [1][2][3][4][5][6][7][8][9][10]. The purpose of the surveillance is to confirm cases and to document the BU in suspected provinces in order to allow a better case management. This surveillance during the three years shows essentially an overall proportion of 26.2% PCR positive samples and in Ziehl -Nelsen, the proportion was low (7.2%). These results corroborate those in the literature which reports that the ZN is less sensitive [1][2][3].
The reported case confirmation shows that Buruli ulcer is a growing threat in DRC and this requires good surveillance of the disease for better determination of the extent of the problem in the country and also ensure good case management in order to avoid complications. However, the proportion of 26.2% reported in this series is lower than those of 35.9% and 75%, observed respectively by [5,7] but it is higher than that obtained by [6]. The difference in Therefore, the hydrographic factor appears to be the determining factor in the outbreak of the disease in this region [9][10][11][12]. he City of Kinshasa also has marshy parts and we had confirmed the cases although the proportion of positive samples is low (6.9%). That is why we must impose and sustain the campaigns of information and sensitization of communities at all levels to help patients to consult in time and avoid the worst because traditional knowledge of the disease remains dominant and linked to a bad curse. a double social problem of school drop-out and reintegration to be solved by the community [14]. Regarding samples analyzed in the laboratory, 86.1% were swabs. This is related to the advanced stage of the disease where we find more ulcerations of different dimensions [5,[10][11][12][13][14][15][16]. Our results are in agreement with those in the literature which show that in many countries where Buruli ulcer is endemic,70 to 100% of patients present with ulcerative lesions and 0 to 30% with non-ulcerous lesions [1][2]have also reported in their series a predominance of ulcerous lesions [5,6,[15][16].

Conclusion
Confirmation of cases using laboratory methods, gene amplification (PCR) or direct examination of smears, is an essential aspect in the overall management of the disease because the results obtained can guide a set of short-term and medium-term actions to limit the adverse effects of the disease on populations.