Implementing TB Surveillance in Nigeria: Best Practices, Challenges and Lessons Learnt

Introduction: TB Surveillance is a critical component of the global TB response. Comprehensive, accurate and timely information on TB is crucial for an effective TB control program hence the need for a robust tuberculosis surveillance system in all countries that contribute to the global burden of TB including Nigeria. Against this backdrop, an intervention was set in motion to triangulate the information from the health data reporting systems towards improving the overall surveillance system for TB in the country. Objectives: This article highlights the best practices, lessons learnt and challenges associ-ated with the implementation of TB surveillance in Nigeria. In resource-limited settings such as Nigeria where health systems including health information management are sub-optimal, there is a heavy reliance on national and sub-national TB surveillance systems. TB data is mainly reported through the National Tuberculosis Control, however the integrated disease surveillance and response (IDSR) system also provides a platform for TB data collation through the LGA and State disease surveillance and notification officers. Conclusion: Implementing TB surveillance in Nigeria brought to fore the need for a wider engagement of all health facilities in TB control. As a divi-dend of the TB surveillance intervention, quality of care was improved in the private health sector through effective linkages to the commodity management system of the NTP and the national treatment guidelines. Strengthening community health surveillance system was identified as a critical element of Tuberculosis control. Also, the efficiency birthed by the integration of TB surveillance into the IDSR structure opened up other potential opportunities such as a unified capacity building of community informants on all notifiable diseases and the integration of reporting and risk communication for all health issues at the community level.


Background
Public health surveillance is described as the ongoing systematic collection, collation, analysis and interpretation of health information for informed and prompt public health action [1] [2]. Surveillance is the heart and conscience of public health and provides the intelligence required to prevent, avert and manage epidemics [2]. Disease surveillance provides a bedrock for all other public health elements including health promotion, health financing and health policy development. Tuberculosis surveillance is the embodiment of all components of public health surveillance focused on TB data. It describes the monitoring of incident and prevalent cases; risk of infection and deaths as a result of Tuberculosis and the use of such information to control TB epidemics [3]. Demographic, geographic, diagnostics and behavioural data are all relevant in TB surveillance for both human and non-human primates [4] [5] [6]. Comprehensive, accurate and timely information is crucial for an effective TB control program hence the need for a robust TB surveillance system in all countries, including Nigeria, that contribute significantly to the global burden of TB [2] [7] [8].
TB surveillance affords countries and institutions the information required to develop effective strategies, targeted interventions and robust policies to address the scourge of the epidemics [4] [5] [9] [10]. Globally, TB surveillance has been recognized as a critical source of information on the burden and epidemiological pattern of TB [11] [12]. Complete, accurate and timely surveillance data is needed to monitor the quality of TB care [13]. This is even more pertinent in resource-limited settings such as Nigeria where health systems including health information management are sub-optimal and less advanced compared to industrialized countries [8] [14]. Robust health information systems are sufficiently able to assess the burden of TB based on case notification hence some countries can measure TB case incidence directly from their case notification [2]. This is not the case in countries with weak health information systems such as Nigeria. Annually, WHO has estimated the burden of TB in Nigeria and in 2012, a national prevalence survey was conducted to provide an empirical measurement of the incidence and prevalence of TB in the country. According to the 2019 global TB Report, the incidence of TB in Nigeria is 219 (143 -311, 95% CI) per 100,000 populations [15]. This incidence forms the basis for estimating the TB disease burden at national and sub-national levels with large margins of error due to a projected population estimate derived from a national census conducted far back in 2006.

Introduction
Tuberculosis is a disease of public health concern in Nigeria as it contributes significantly to the country's annual morbidity and mortality data [15]. Nigeria has the largest burden of TB in Africa and is among the ten countries accounting for 80% gap in the estimated incident cases and the number of incident cases reported globally [15]. Nigeria's treatment coverage for TB has remained pre-  [15]. In spite of the huge public health issue presented by TB, the national surveillance system remains inadequate and unable to report every suspected and confirmed case of TB.
The Integrated Disease Surveillance and Response (IDSR) was created by WHO in 1988 to address weaknesses in health surveillance systems in the Africa region, however due to weak political will, this system remains poorly funded and unable to achieve its full potentials [17]. This setback in the IDSR has led to the creation of parallel data information systems at the national, state and LGA levels. Key among which is the National Health Management Information System (NHMIS). In country, WHO continues to support the IDSR system to notify epidemic prone diseases, diseases marked for elimination and eradication; and other diseases of public health concern, including TB. The system is however unequivocally focused on acute flaccid paralysis and to a lesser extent, cholera, measles and neonatal tetanus. This is a far cry from the original design of the IDSR which should report 42 priority diseases under surveillance in Nigeria with designated standard case definitions [18]. The flow of information through the IDSR is from prioritized health facilities (based on population and disease bur-

Principles of TB Surveillance in Nigeria
The key construct of TB surveillance is to enable a robust and accurate assessment of the burden and epidemiological pattern of TB towards developing effective program designs and policies to address the TB epidemics. These epidemi-

Best Practices and Lessons Learnt
Engagement of umbrella bodies of general and private medical practitioners served to rapidly expand the coverage of TB services in the private sector. Service expansion in this frequently ignored but thriving sector is critical and particularly so in settings where the vast majority of clients rely on their services [19]. A subtle and dynamic interplay of factors enhanced the engagement with the private sector which by nature thrives on profit generation. The facilities so engaged were linked to the NTP logistics system through which they had access to free anti-TB medicines for their patients. This improved quality of TB care in the engaged facilities by removing the need for the procurement of sub-standard, anti-TB medicines from unregulated markets [20]. Consequently, the cost of treating TB patients was reduced and this resulted in better patient adherence and treatment outcomes. Other incentives include the supply of reagents for AFB Microscopy.
Leveraging on technology enhanced the timeliness and usefulness of TB surveillance data and ensured prompt interventions for clients. Social media platforms such as WhatsApp were used to create groups for medical doctors in the private sector to enable real time notification of presumptive and diagnosed TB cases. This approach greatly shortened the time between diagnosis and treatment enrolment and minimised pre-treatment loss to follow up which was hitherto prevalent in the private sector [21]. Also, the platforms were used for communicating updates on TB treatment guidelines and for the provision of

Challenges with TB Surveillance in Nigeria
Sub-optimal TB notification has remained an issue for the TB Program in Nigeria. This challenge can be attributed to weak policy framework on mandatory notification of TB by all health facilities and the outcome is under-reporting of TB cases especially in facilities that are not engaged by the National TB program as TB treatment centres. Considering that over 80% of health facilities are yet to be included in the data management system of the NTP, this presents a major challenge for TB surveillance. This is further exacerbated by a weak community surveillance system which means that persons who are unable to access health services are also missed in the community. These challenges are not unrelated to the poorly funded IDSR system, low awareness about TB in the general population and the failure to achieve universal health coverage in Nigeria.
Poorly implemented regulatory framework results in multiplicity of data man- whom they are expected to report notifiable diseases; while those who have knowledge are hindered by lack of infrastructure and adequate logistics [22].
Clinicians have a significant role in disease surveillance and reporting given that they have the ability to cascade knowledge down to other cadres of the health care system and therefore should have their capacity properly built on the use of the IDSR structure [18]. Many healthcare workers have adequate knowledge of the use of IDSR003 form but have very limited knowledge of the use of other very critical IDSR forms [23]. Lack of robust training on disease surveillance affects the effectiveness of the surveillance system; this is also reflected in the absence of feedback to healthcare workers in peripheral facilities [24].

Implication for Future Studies
Future studies should explore the empirical measurement of the impact of TB surveillance on TB control in Nigeria. Investigating the relevance of non-traditional surveillance data such as pharmacy and patent medicine vendors' dispensing information to TB surveillance in Nigeria may also provide useful insights.