Community-based surveillance programs in Cameroon, Chad, Niger and the DRC: a comparative assessment of integration in humanitarian crisis contexts

Abstract

Background

Increasing community involvement to anticipate and organize a rapid response to epidemics remains a major challenge. From 2022 to 2025, the French Red Cross, together with host national Red Cross Societies, supported the Ministries of Health in Cameroon, Chad, Niger and the Democratic Republic of Congo (DRC) in setting up community-based epidemiological surveillance (CBS). On the basis of prevention, early detection and notification of suspected cases, these programs mobilize community players trained in early warning. This article aims to contribute to the limited evidence on CBS effectiveness in humanitarian crises by describing and evaluating the implementation of community-based surveillance in these countries.

Methods

The evaluation of CBS systems followed a mixed retrospective-observational multicentred approach, combining quantitative indicators (responsiveness, verification and sensitivity) and qualitative indicators (simplicity, adaptability, acceptability and perceived usefulness) collected from key stakeholders.

Results

A total of 186 stakeholders involved in the CBS program were interviewed. Combined with quantitative epidemiological data, these findings seem to confirm the advantages of the CBS: its responsiveness, perceived usefulness by the stakeholders involved, simplicity, adaptability, acceptability and proximity to the community. 82% of alerts were verified within 24 h, and 76% of these alerts were validated by a supervisor or health center manager. Apart from the DRC, very few biological samples have been taken; however, the stability of the system cannot be accurately assessed. The sustainability of the CBS, while desired by most stakeholders, remains subject to the question of how it will be financed.

Conclusion

This evaluation confirms the usefulness of the CBS in various humanitarian contexts but highlights areas for improvement, including logistical support, human resources, community player training, healthcare access (especially for women), and microbiological testing. The long-term viability of CBS depends on securing sustainable funding and strengthening healthcare systems to empower local communities to manage future epidemics.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13031-025-00724-7.

Introduction

Infectious diseases remain a major cause of morbidity and mortality around the world, particularly in sub-Saharan African countries [1]. Recent epidemics associated with the emergence of pathogens (mpox, SARS-CoV-2, Ebolavirus, etc.) all highlight the challenges associated with an effective epidemic response, namely, strengthening prevention measures, early case detection and the responsiveness of healthcare systems. This is especially true for low-income countries, where the shortage of passive surveillance systems and primary health care centers, as well as the population’s difficulties in accessing the health care system, the lack of awareness of these transmissible diseases and the lack of trust in public authorities, are all obstacles to early detection of, and therefore early response to, an epidemic [2, 3].

Defined as “the systematic detection and reporting of events of interest to public health within a community, by members of that community” [4], community-based surveillance (CBS) can be based on the recognition of defined syndromic frameworks or on the reporting of any unusual event of interest to public health (event-based surveillance, or EBS). It has been repeatedly recognized as a key tool for improving the early detection of outbreaks [5–13], including in the context of humanitarian crises [14–17]. While the implementation of these programs can take a variety of forms [8], there remains an overall lack of evaluation of these CBS programs in the literature [18].

Present in almost 191 countries through its National Societies, the International Red Cross and Red Crescent Movement has been one of the world’s leading humanitarian organizations since it was founded in 1859. Supported by volunteers from a wide range of backgrounds, its involvement in communities remains strong and recognized, particularly in the promotion of health and the fight against epidemics. For several decades, the French Red Cross has been supporting the national societies of several countries in sub-Saharan Africa in their efforts to prevent and raise awareness of diseases with epidemic potential. In this context, as part of the Pilot Programmatic Partnership (PPP) financed by the European Union (DG ECHO), several community-based surveillance projects were set up in Cameroon, Chad, the Democratic Republic of the Congo and Niger. The aim of these projects was to strengthen the capacity of local communities and stakeholders to anticipate, respond to and recover from humanitarian and health crises and, more specifically, to improve detection, prevention and response to epidemics by integrating community-based surveillance into national epidemiological monitoring systems.

The aim of this study is to contribute to the limited evidence on CBS effectiveness in humanitarian crises by describing and evaluating the implementation of community-based surveillance in these countries.

Project background and description

Humanitarian background

The implementation of CBS in these 4 countries (Cameroon, Chad, the Democratic Republic of the Congo and Niger) was carried out at the request of public authorities and Host National Society (HNS) in complex humanitarian contexts, which differed significantly from one country to another.

In Chad, the CBS was deployed in Mayo-Kebbi East Province beginning in June 2023, an area characterized by rural poverty, persistent insecurity (intercommunal conflicts, kidnappings), and recent floods that damaged infrastructure and displaced populations [19]. As of October 2024, at the request of the authorities, the Sila region, bordering Sudan and experiencing significant population movements, was also included.

In Cameroon, CBS was implemented in four departments of the Extreme North region starting in January 2022. This region, with a mixed climate ranging from arid to tropical, also faces a complex humanitarian situation due to regular incursions by nonstate armed groups, leading to population displacements and episodes of floods and droughts [20].

Initially, deployed in the Tillabéri region in Niger, activities were later transferred to Tahoua and Maradi in June 2024 due to evolving security risks and at the request of local authorities. These regions, bordering Nigeria and Mali, host significant population movements due to incursions by nonstate armed groups in neighboring countries.

In the DRC, the CBS was finally established in the Uvira territory of South Kivu in January 2023. This region has been affected by a regional interstate conflict since January 2025 and faces a long-standing humanitarian crisis, including security instability, mass population displacement, seasonal floods, food insecurity, and limited access to clean water [21].

Project implementation

The selection of health areas for the CBS project was performed collaboratively with local authorities and HNSs on the basis of 4 criteria: epidemiological situations, the absence of prior CBS implementation, the willingness of host countries and fund providers, and the feasibility of accessing health centers and communities while considering security risks.

CBS activities were implemented in line with the WHO and IFRC recommendations. Volunteers were recruited on the basis of their engagement with the Red Cross/Red Crescent movement, health training, local language proficiency, and community acceptance. In Niger, existing community health workers were prioritized for recruitment. The diseases under surveillance were selected in collaboration with local health authorities and HNSs on the basis of the epidemiological situation in health areas (cf. Table 1). Suspected cases were defined on the basis of the WHO [22] and the IFRC definitions [23] (cf. Appendix 1). Notably, all alerts were verified and investigated where appropriate without defining an alert threshold. Volunteers received daily allowances funded by the French Red Cross (FRC).

Table 1.

Table of the different health areas and diseases under surveillance involved in CBS

Country	Health area	Estimated population	Recruited volunteers	Diseases under surveillance
Cameroon (Far North)	Kousseri district Amchédiré, Hilé-Haoussa, Kala-Kafra, Logone-Birni, Madana, Madagascar, Ndjagaré, Ngodéni, Par-par, Zimado, Zina Maroua III district Birio, Dargala, Djarengol Kodek, Djoulgouf, Dougoi, Kaewo, Kodek, Kongola, Ouro-Zangui, Yoldeo Moutourwa district Damai, Foulou, Mouda, Moutourwa, Titing Vele district Begue-Palam, Djafga, Doreissou, Gabaraye, Kaikai, Kartoua, Kouro-Mokdaye, Madalam, Vele, Widigue	Project population for 2017 (INS Cameroun) 362 888	158	­ Cholera ­ Yellow fever ­ Acute respiratory infections ­ Mpox ­ Acute flaccid paralysis ­ Rabies ­ Measles ­ Guinea worm + EBS
Chad (East Mayo Kebbi and Sila regions)	Bongor district: Biliam Oursi, Bongor urbain 1, Bongor urbain 2, Bongor Sieke, Djoumane, Maguine Goz-Beida district Doroti, Kerfi	Project population for 2024 (DPSN, Tchad) 75 000	183	­ Cholera ­ Yellow fever ­ Acute respiratory infections ­ Mpox ­ Acute flaccid paralysis ­ Rabies ­ Measles ­ Guinea worm ­ + EBS
Niger (Madari and Tahoua region)	Guidan-Roumdji district Chadakori, Indoto Almou, Sae saboua, Souloulou, Urbain Mayahi district Guidan Taweye, Mallamawa Kaka, Nanaye, Urbain Mayahi Tessaoua district Baoudeta, Dan A’I, Gournaka, Guindaoua, Toki Madoua district : Eroufa, Manzou, Takorka Keita district Grado nord, Hiro, Labanda, Urbain Keita	Project population for 2023 (Carte sanitaire, Niger) 575 185	415	­ Cholera ­ Yellow fever ­ Meningitis ­ Mpox ­ Acute flaccid paralysis ­ Rabies ­ Measles ­ Neonatal tetanus + EBS
Democratic Republic of Congo (South Kivu)	Uvira health zone Kabindula, Kabindula Etat, Kalundu Etat, Kasenga CEPAC, Kavimvira:, Kilomoni, Mitumba, Mulongwe, Saint-Paul, Tanganyika, CTC Uvira	Project population (Health pyramid for health zones, Ministry of Health, 2024) 209 645	128	­ Cholera ­ Acute respiratory infections ­ Mpox ­ Measles

Volunteer training

Volunteers underwent training delivered by HNSs and the FRC, which focused on recognizing diseases under surveillance and prevention measures (cf. Appendix 1). This training also included sensibilization of zoonoses and the One Health approach. Knowledge assessments were conducted before and after training, with refresher courses provided periodically. Trainer training sessions were also held on the same themes for volunteer supervisors and health center managers. All those who attended the training sessions received daily allowances.

Alert reporting procedure

Volunteers conducted regular home visits in a village or neighbourhood assigned to them, coordinated by a designated supervisor. Upon detecting a suspected case, volunteers reported to the supervisor, who confirmed the alert on the basis of community case definitions. If the supervisor was unavailable, the alert was escalated to the health center manager, who provided care and conducted microbiological sampling when possible. Each home visit was carried out with the agreement of the community or its designated chief. Alerts were recorded and regularly transmitted, so that they could be integrated into other epidemiological surveillance systems and, more generally, into each country’s integrated disease surveillance and response system (IDSR), to district and regional health authorities (Fig. 1).

Fig. 1.

Flow chart for reporting a suspected case detected by a community volunteer

These alerts were reported by various means. The vast majority of alerts used a community notification form (see Appendix 2) in parallel with reporting by telephone (SMS and Nyss system). In Niger, however, volunteers were also able to report these alerts via forms within the Kobo Collect^® application—simplifying collection and enabling faster transmission of the alert (cf. Appendix 3). Confirmed cases taken into care in health centers were then reported—in the same way as the passive epidemiological surveillance set up in various countries—to the epidemiological surveillance officers in the health district and then to the regional directorate of the Ministry of Health (DHIS2 since 2023 for Cameroon, Niger and the DRC).

Methods

The evaluation of these CBS programs is based on a descriptive, mixed (quantitative and qualitative), retrospective and multicentred approach in compliance with the recommendations published by the WHO [22] and the IFRC [23].

Quantitative evaluation

For the quantitative evaluation, all alerts issued since the introduction of the CBS (SMS, form, Kobo, etc.), up to March 01, 2025, in the 4 countries were analysed. This included all alerts issued by the CBS, excluding alerts issued by epidemiological surveillance systems in place. Notably, the variables collected for each alert varied significantly from country to country. For the sake of comparability, only 13 variables were ultimately retained for this evaluation (date of notification, country, district, health area, age of suspect case, sex of suspect case, type of alert, validation of alert by supervisor/health center, verification of alert within 24 h, verification by a member of the referring health center, transfer to the referring health center, sample collection, test result).

Qualitative evaluation

For the qualitative evaluation, all stakeholders directly or indirectly involved in the implementation of the CBS project (health district managers involved in epidemiological surveillance, members of provincial or departmental Red Cross committees, managers of the health areas concerned, community volunteers from national companies involved in CBS, etc.) were interviewed via semi structured questionnaires written in French (see Appendix 5). Open interviews were also conducted with community volunteers, health center managers and district chiefs in East Mayo-Kebbi (Chad). For the community volunteers, sampling was carried out based on a random draw with stratification by sex (female/male ratio of 1:1) and health area (minimum of 1 community volunteer per health area). A target of at least 20 volunteers per country was set. A supplementary list of volunteers was also drawn to compensate for participants who could not be reached during the evaluation period or who refused to take part in the evaluation. The interviews were conducted in French by members of the FRC and the HNSs, keeping the investigators’ direct involvement in the program or hierarchical relationship with the interviewee to a minimum. The open-ended questions asked by the various participants were then reviewed independently by two of the authors and grouped into main themes for analysis and synthesis.

Ethical considerations

The ethical principles associated with research were observed. Each participant in the qualitative evaluation received oral and written information (see Appendix 4), describing the purpose of the evaluation, his or her rights with regard to the answers collected, and how the information gathered would be processed. Written consent was obtained from all participants. All information that could lead to the identification of participants or suspected cases was removed.

Analysis criteria

The evaluation was carried out using the maximum number of criteria expected of an available epidemiological surveillance system [24, 25]. Based on the main comparable articles identified [5, 14, 15, 17] and the indicators summarized by A.W. Crawley et al. [18], several evaluation criteria were used (perceived usefulness, simplicity, reactivity, alert sensitivity, acceptability, adaptability, sustainability, etc.). A definition for each of these criteria is given in Appendix 5.

Quantitative epidemiological data and responses to the qualitative evaluation were collected via Excel software (Version 2503 Build 16.0.18623.20116). No analysis software was used for this data. Statistical analysis of the quantitative results was carried out via R studio software (version 2024.12.1). Confidence intervals were calculated via the binomial distribution (exact method), and statistical tests were performed via the chi-square test.

Results

Based on the criteria expected for an epidemiological surveillance system [24, 25] and the indicators summarized by A.W. Crawley and al. [18], for the sake of clarity, as well as to maintain a chronological order in the implementation of the project, the results are here structured into broad themes: “Profiling and training of community volunteer”, “target population and alerts” for details of identified suspected cases, “simplicity and implementation of CBS”, “alert transmission”, “responsiveness and sensitivity”, “perceived usefulness and community acceptability”, and finally “sustainability”. A definition for each of these criteria is given in Appendix 5.

Profiling and training of community volunteers

The qualitative evaluation took place from 09/02 to 07/04/2025. Notably, owing to the geopolitical situation in Kivu during the data collection period, it was not possible to interview all the stakeholders planned for the DRC. A total of 186 stakeholders involved in the CBS program were interviewed, including 86 community volunteers, 73 health center managers, 12 representatives of the Red Cross movement at the departmental/provincial level and 17 epidemiological surveillance managers in the health districts. For the volunteers surveyed, the average age was 40.2 years (95% CI [37.7–42.7]), with 45.3% females interviewed (39/86, CI95% [35–56]). The main responses of the community volunteers to the questionnaires are summarized in Fig. 2.

Fig. 2.

Proportion of positive responses from the community volunteers surveyed (n = 86) to the various questions. The average positive response for each question is shown on the right (%, 95% CI)

A total of 884 community volunteers were recruited for this CBS program, 32% of whom were women (283/884, 95% CI [28.9–35.2]). The majority (65.1%) of respondents (56/86, 95% CI [54.1–75.1]) had no financial resources apart from daily allowances, and several of them (29.1%, 25/86) were working as community relays before the project. Overall, most of the volunteers (71%) felt that CBS training was sufficient (66/86, 95% CI [66.4–85.2]). However, during the open interviews, several participants (community volunteers, health center managers, Red Cross representatives) expressed a desire for more in-service training in the future. Moreover, several emphasized that more sustained training for volunteers with less health knowledge would be more appropriate. Finally, some of those in charge of epidemiological surveillance in the health districts mentioned the need for more widespread training in CBS and communicable diseases (all community relays, including those in areas not included in the project, community leaders, etc.).

Target population and alerts

Table 2 summarizes the main quantitative quality indicators for community-based surveillance systems. A total of 6.415 alerts were reported between the implementation of the various CBS programs and 01/03/2025 (3.352 alerts for Cameroon, 1.231 for Chad, 1.482 for Niger, and 530 for DRC).

Table 2.

Main quantitative indicators associated with the quality of the community-based surveillance system - general and by country

Country	Cameroon	Chad	Niger	DRC
Estimated target population	362.888	75.000	575.185	209.645
Community volunteers recruited	158	183	415	128

Target population
Number of alerts received (until March 2025)	3.352 (since January 2022)	1.231 (since June 2024)	1.482 (since January 2023)	530 (since June 2023)
Sex of suspected cases (female) (%, 95% CI)	42,3% (41,1–43,6)
Sex of suspected cases (female)	1.271 (43%)	596 (48,4%)	270 (50,9%)	487 (32,9%)	< 0,001
Age of suspected cases (mean, SD)	9.16 years old (12,18)	NA	NA	21.7 years old (18)	< 0,001

Quality indicators for the community-based monitoring program
Verification by health center/supervisor (%, 95% CI)	92,7% (91,8–93,3)
Verification by health center/supervisor (%)	93,4%	89,8%	96%	94,2%
Verification of alert within 24 h (%, 95% CI)	82.1% (81.2–83)
Verification of alert within 24 h (%)	72,7%	89,8%	96%	89,6%	< 0,001
Alert validation (%, 95% CI)	76.4% (75,2–77.6)
Alert validation (%)	89,1%	35,6%	NA	94,1%
Sample taken (%, 95% CI)	3% (2,7 − 3,5)
Sample taken (%)	148 (12,2%)	58 (4,7%)	NA	478 (100%)
Positive biological sample (%)	1 (0,7%)	2 (3,6%)	NA	453 (94,8%)

These CBS programs covered a predominantly male population, with only 42.3% of suspected cases involving women (IC95% [41.1–43.6]). However, there was a disparity between countries, with women accounting for 50.9% of suspected cases in the DRC versus just 32.9% in Niger (p < 0.001). The age of suspected cases was reported only in Cameroon (9.2 years on average) and in the DRC (21.7 years), again with differences between countries due, among other things, to the pathologies under surveillance.

The type of alerts reported also differed significantly from country to country, with each CBS program having opted to monitor different pathologies. Overall, however, suspected cases of measles and yellow fever accounted for the bulk of alerts in Cameroon, Niger and Chad, which is in line with epidemiological trends reported over the same period (WHO and Africa CDC epidemiological reports). In the DRC, on the other hand, alerts were associated mainly with suspected cases of cholera (58.9%) or Mpox (38.1%), which is again in line with epidemiological data from this period. Most CBS programs also involve event-based surveillance (EBS), reporting diseases associated with the veterinary world—mainly suspected cases of rabies (216) and epizootics (39). Notably, a significant proportion of alerts in Niger (34.3%) were labelled “Other unusual event”, which were mainly suspicions of scabies and malaria (see Table 3).

Table 3.

Distribution of alert types by country

Disease	Cameroon	Chad	Niger	DRC
Cholera (n,%)	165 (4,9%)	1 (0,1%)	32 (2,2%)	312 (58,9%)
Yellow fever (n,%)	931 (27,8%)	446 (36,2%)	117 (7,9%)	0
Acute respiratory infections (n,%)	139 (4,1%)	6 (0,5%)	148 (10%)	3 (0,6%)
Bacterial meningitis (n,%)	36 (1,1%)	0	16 (1,1%)	0
Mpox (n,%)	3 (0,1%)	4 (0,3%)	0	202 (38,1%)
Acute flaccid paralysis (n,%)	372 (1,1%)	92 (7,5%)	88 (5,9%)	0
Rabies (n,%)	195 (5,7%)	0	21 (1,4%)	0
Measles (n,%)	1 409 (42%)	523 (42,5%)	504 (34%)	4 (0,8%)
Guinean worm (n,%)	18 (0,5%)	57 (4,6%)	11 (0,7%)	0
Neonatal tetanus (n,%)	2 (0,1%)	0	12 (0,8%)	0
Epizootic disease (n,%)	15 (0,4%)	0	24 (1,6%)	0
Other unusual events (n,%)	70 (2,1%)	102 (8,3%)	509 (34,3%)	9 (1,7%)

Simplicity and implementation of CBS

On a practical level, the number of neighbourhoods or villages visited per week varied greatly according to the volunteers surveyed and the country. Overall, 37.2% of the volunteers surveyed (32/86) said they were in charge of more than 3 neighbourhoods/villages—mainly in Cameroon (70.8% of the volunteers, 17/24). Conversely, in Chad, 48.4% of the volunteers surveyed (15/31) covered 1 neighbourhood/village. This disparity is probably largely due to the level of community volunteer supervision, which varies widely from country to country. Taking into account the most recent demographic data available (see Table 1), it can be estimated as a rough guide that a community volunteer was on average responsible for the epidemiological surveillance of 2.300 inhabitants (IC95% [2.000–2.700]) in Cameroon, 1.400 inhabitants (IC95% [1.260–1.530]) in Niger, 1.640 inhabitants (IC95% [1.380–1.960]) in the DRC and 410 inhabitants (IC95% [350–480]) in Chad.

The number of weekly outings was also very heterogeneous among the population surveyed, with 15.1% of the volunteers (13/86) outing one week, whereas the majority (45%, 39/86) outings 3 times a week. The lack of logistical resources, especially for journeys—particularly during the rainy season—was one of the recurring points raised during the unstructured interviews. Overall, 33.7% of the volunteers surveyed (29/86, 95% CI [23.9–44.7]) felt that they had too many neighbourhoods/villages to cover, particularly in Cameroon (15/24) and Niger (6/31).

With respect to the implementation of the CBS, most of the volunteers surveyed (75.6%) considered it straightforward (65/86, 95% CI [65.1–84.2]). Among those who reported difficulties at the start of the project, community mistrust, workload assigned to volunteers and lack of logistical support were among the main causes cited by the volunteers interviewed. Most, however, report that this mistrust was overcome over time, and some advocate greater involvement of community leaders in the future.

On the other hand, this mistrust of the community was not perceived as a major difficulty at the start of the project by the other CBS stakeholders: 84.9% (62/73, 95% CI [74.6–92.2]) of health center managers considered that CBS and its integration were simple to implement, even if several of them (16.4%) recognized low community acceptance at the start of the project as a hindrance (12/73, 95% CI [8.8–27]). Other difficulties mentioned by health centre managers include the lack of communication of biological results (42.5%), the lack of global funding (60.3%) and the lack of coordination between stakeholders (27.4%) (see Fig. 3).

Fig. 3.

Positive response rate to the questions by the health centre managers surveyed (n = 73). The average positive response for each question is shown on the right (%, 95% CI)

Alert transmission, responsiveness and sensitivity

For the vast majority of suspected cases, the 24-hour time limit between detection and verification was respected (82% CI95% [81–82.9]). In Niger, the proportion of alerts was as high as 96%, whereas it was 72.7% in Cameroon (p < 0.001; Table 2). Similarly, approximately 88.4% of the volunteers questioned (76/86, 95% CI [79.7–94.3]) said that they had returned within 24 h of reporting an alert to the health centre supervisor or manager. Notably, the transmission of information and alerts was digitized in Niger (using the Kobo Collect^® application), which may explain why, unlike in the other countries, no volunteers reported any obstacles to the transmission of alerts. For the other countries, several of the volunteers questioned reported an overall lack of logistical support (lack of telephone credit, means of travel, etc.); 22% of them (19/86, 95% CI [13.9–32.3]) reported having encountered an obstacle in transmitting alerts.

Unfortunately, the sensitivity of alerts is not assessable in all countries—the validation of alerts by supervising volunteers who are not notified in Niger. However, it remained high for Cameroon, Chad and DRC; 76% of alerts (IC95% [75.2–77.6]) were validated (compliance with the community definition of a suspect case). However, this figure conceals a significant disparity between countries, with 94.1% of alerts being validated in the DRC compared with 36.2% in Chad.

Finally, sampling of suspected cases for microbiological confirmation was very rare (3% (2.7–3.5) of alerts), except for DRC, where 100% of the validated suspected cases were sampled. This failure to collect and report biological results is in addition to recurring complaints from community volunteers and health officials; as microbiological sampling is largely centralized at the national/regional level (N’djamena in Chad, Garoua in Cameroon, etc.), delays in obtaining results are a major obstacle to the epidemic response. In addition, the results are communicated only to patients if they are positive, which can undermine the legitimacy of the work of community volunteers and partly explain the population’s initial distrust.

Perceived usefulness and community acceptability

All the volunteers surveyed (86/86, 95% CI [95.6–100]) testified to the perceived usefulness of CBS and considered it to be a relevant means of preventing epidemic CBS in their health area. Most were able to cite examples of suspected cases detected and referred to the health centre thanks to CBS. The vast majority (98.8%) noted concrete improvements in the health situation in their community since the system was set up (85/86, 95% CI [93.7–100]), citing increased attendance at health centres, better coordination between local health stakeholders, and greater awareness among the population of hygiene measures and the importance of vaccination. Notably, volunteers and health area managers also reported that the CBS, as implemented in Cameroon, Niger and Chad, was combined with EBS, highlighting its adaptability. All the health centre managers (73/73, 95% CI [95.1–100]) considered CBS to be a relevant means of detecting the emergence of a hitherto unknown pathogen/disease in their health area.

Despite the initial mistrust of the community reported at the start of the project, acceptance by the target populations was generally good. A total of 88.4% of the community volunteers (76/86, 95% CI [79.7–94.3]) stated that the community had fully accepted their surveillance work; the others preferred to speak of partial acceptance, although none reported rejection by the population. All of them also felt that their work had been recognized and supported by the local authorities (86/86, 95% CI [95.8–100]). A total of 97.7% of them (84/86, 95% CI [91.9–99.7]) said that the CBS implemented corresponded to the needs of the community.

The same usefulness was perceived by departmental/provincial Red Cross managers and health district surveillance managers - all of whom (12/12 and 17/17 respectively) felt that the CBS had had a significant effect on the detection and management of epidemics (see Fig. 4).

Fig. 4.

Rates of positive responses from epidemiological surveillance officers in the health districts surveyed (n = 17) to the various questions. The average positive response for each question is shown on the right (%, 95% CI)

Sustainability

Most of the players involved in the CBS (community volunteers, health centre managers, district managers and representatives of the provincial Red Cross) were in favour of continuing the program and extending it to health areas not covered. A total of 95.3% (82/86, 95% CI [88.5–98.7]) of the surveyed volunteers said that they wanted to continue CBS after the end of the project. The same enthusiasm was found among health centre managers (73/73, 95% CI [95–100] wished to continue after the end of the project), the departmental/provincial Red Cross representatives interviewed and health district managers. A total of 73.3% of the volunteers questioned (63/86, 95% CI [62.6–82.2]) are integrated as community relays outside the project—including other public health programs (awareness-raising, vaccination, etc.)—compared with 29.1% (25/86) at the start of the project. Similarly, 63% of health centres (46/73, 95% CI [50.9–74]) indicated that they had trained community relays outside the Red Cross Movement in CBS, most of whom had reported suspected cases during the project (52/73, 95% CI [59.4–81.2]).

However, only 58.3% of the departmental/provincial Red Cross committees (7/12, 95% CI [27.7–84.8]) indicated that they would be able to continue their activities after the end of the project. In terms of a sustainable source of funding, the majority of health district representatives envisaged community participation (83%), national funding (66.7%) or regional/provincial funding (25%) as the solution. A total of 41.7% of the health district representatives interviewed considered funding for CBS activities from an international donor to be a permanent source of funding.

Discussion

The results of this study seem to confirm that the CBS fulfils several of the objectives expected of an epidemiological surveillance system. By actively seeking out cases through community members, it appears to enable early detection of transmissible diseases, with responsiveness to the epidemic response of health centers and simplicity in its implementation. All the stakeholders involved in this CBS project also seem to emphasize the perceived usefulness of this program and its adaptability in the event of the emergence of a new pathogen. Finally, they all seemed to report that the program was well, or even very well, accepted by the community. All these aspects seem to confirm the relevance of CBS in humanitarian crisis contexts, as reported in other comparable programs [5, 6, 14, 15].

Notably, this CBS program was part of a wider epidemic prevention and preparedness program. A number of community volunteers took advantage of their home visits to raise awareness of diseases with epidemic potential that were under surveillance and to promote hygiene and vaccination; most of them noted greater receptiveness and adoption of good practices within the community. In most countries, notably Cameroon, a One Health approach has also been adopted, including raising awareness of zoonoses. The effects of this CBS therefore potentially extend beyond the scope of the diseases covered by community-based surveillance.

Several weaknesses of this program, however, are worth highlighting. First, in terms of logistics, the testimonies of community volunteers and health centre managers in the 4 countries highlight their lack of resources; in terms of communication (telephone credit,.), journey (boots during the rainy season, provision of bicycles for community volunteers, etc.), and the computerization of alerts (assistance with database management, improved integration of alerts into DHIS 2, etc.). Responsiveness to alerts is one of the key elements of CBS [15, 18]; and computerized transmission and processing of alerts are important ways of improving this responsiveness [26, 27]. The use of tablets equipped with the Kobo Collect^® application in Niger, as well as the use of Nyss [14] in all countries, were here efforts to improve alerts transmission. However, feedback from the volunteers we interviewed shows that even basic logistical support (telephone credit, bicycles, etc.) can be decisive for the CBS’s responsiveness. The workload of volunteers is also an important factor: several community volunteers interviewed reported that the number of neighbourhoods/villages in Cameroon, Niger and the DRC was too high, higher than in most comparable CBS programs [17]. The same observation was made by most of the health centers, health district managers and members of the Cameroonian, Nigerian and Congolese Red Cross involved in CBS. In addition to enhanced logistical support, a larger contingent of volunteers should therefore also be considered for future CBS programs.

The sensitivity of alerts also remains a major area for improvement. Although it is on the same order of magnitude as most comparable CBS programs [5], it could be assessed here only by validation of the syndromic case by a volunteer supervisor or health center manager. Too few microbiological tests were carried out, which was in keeping with the project’s aim of building a sustainable CBS system integrated into the country’s health system. The lack of tests carried out, and the fact that results are communicated only in the event of a positive result, is, however, a major obstacle to the trust placed in community volunteers and ultimately to the epidemic response. This is partly due to national decisions to centralize microbiological analyses (N’djamena for Chad, Garoua for Cameroon, etc.) in a context where road infrastructures are often unsuitable for emergency transport. It might therefore be appropriate to lobby public authorities to decentralize these analyses to the regional or even district level. On a broader level, however, it should be remembered that the weakness of laboratory networks in low- and middle-income countries remains a recurrent obstacle to the implementation of the Integrated Disease Surveillance and Response (IDSR) strategy [28].

Training is also a major factor in the success of CBSs. Here, most volunteers surveyed and health center managers expressed a desire for more ongoing training, as well as initial training for all, better adapted to everyone’s level of health knowledge, which is in line with other evaluations reported in the literature [5, 15, 26]. The complexity of initiating the project, as reported by some, underlines in part the need to reinforce the training of committed volunteers but also, more widely, of the actors involved in CBS. Furthermore, outside the DRC, most CBS programs cover a multitude of pathologies and are associated with event-based surveillance (EBS). This strategic choice, made to better respond to needs by nature and evolving in humanitarian crisis contexts, has several advantages and disadvantages. This allows for greater adaptability and better integration of the CBS into the local health system. It also reinforces the integration of a One Health approach and has enabled the detection of several epizootic or zoonotic diseases (rabies, hemorrhagic fever, etc.). At the same time, however, it can lead to confusion in the recognition of community cases by volunteers, thus limiting the specificity of these alerts and ultimately the effectiveness of the epidemic response by inducing too many false alarms. EBS should therefore also be pursued with simplicity in mind, concentrating on a few pathologies under surveillance, as is the case in most CBS programs [8].

The stability of these CBS programs could not be evaluated, as the weekly number of home visits was reported only in Chad. This is a limitation for evaluating these programs compared with other programs [14, 15]. Weekly reporting by volunteers of the absence of identified alerts (“zero report”) is recommended by the WHO and IFRC guidelines for SBC systems [29]. This choice was, however, made to strengthen integration into local health systems and ensure the sustainability of the SBC after the project.

Additionally, the low proportion of women among suspected cases, particularly in Niger, highlights the need to integrate gender considerations in future CBS programs; only 32% of recruited volunteers are women. This also underscores the challenges in accessing healthcare for affected populations, which remains a significant obstacle to the relevance of CBS in these health areas. Finally, several district health officers and Red Cross representatives noted initial community mistrust as a barrier to CBS implementation. Community leaders and traditional practitioners should be more involved in future CBS programs, as emphasized by several community volunteers and health center managers.

These limitations raise the question of the sustainability of this CBS program. Several factors remain encouraging first and foremost: all those involved have shown their enthusiasm and their determination to continue. The training by the health centers of community relays, outside the project, and the Red Cross Movement, which operates CBS and has reported alerts, is also reassuring in this sense, since it underlines the integration of CBS into the health system. There are, however, a number of dark spots in this picture. First, it should be noted that most volunteers surveyed had no resources other than Red Cross benefits. The nonpayment per diems in 2023 and 2024 in Cameroon and Chad led to a drop in alert notifications, indicating that, despite the sincere commitment of these volunteers, the dailies allowance is still necessary to ensure the sustainability of CBS activities—if only to cover travel costs, telephone credit, etc.

The question of funding is—to our knowledge—not widely addressed in the literature [5, 26] and is the subject of debate among the stakeholders interviewed (district manager, health area manager, local Red Cross representative). Most health district managers propose the hypothesis of financial participation by the community, although most stress the need for public authorities to participate at the national level. For 41.7% of them, international players remain indispensable for the sustainability of these epidemiological surveillance activities. This question also highlights the overall lack of investment in the health systems of Cameroon, Chad, Niger and the DRC. While it remains an effective means of detecting and responding to epidemics, strengthening the capacity of local communities and stakeholders to anticipate, respond to and recover from humanitarian and health crises will probably not be possible without strengthening the local healthcare system (logistical reinforcement of healthcare structures, financial models for the management of the main pathologies, etc.).

Finally, several limitations of this study must be noted. This evaluation, although carried out as much as possible by staff not directly involved in the CBS, was first and foremost carried out by FRC staff. Despite the desire for impartiality and the need to carry out standardized interviews with answers as unbiased as possible, this constitutes a conflict of interest potentially influencing the results observed. Moreover, the interviews were conducted in French, which may have led some volunteers to misunderstand the questions. The absence of several pieces of information—the lack of notification of alerts verified by a healthcare professional, of systematic microbiological testing or of “Recording a Zero” for stability—also limits the interpretation of quantitative indicators, including sensitivity and the epidemiological events identified. It was also not possible to survey a representative sample of the population targeted by this program, and acceptability was only gathered through the perceptions of community volunteers and health center managers. Finally, it was not possible to carry out a cost-efficiency evaluation of this program, which could have enriched this evaluation.

Conclusion

This evaluation of programs set up in Cameroon, Chad, Niger, and DRC confirms the advantages proposed for the CBS: its responsiveness; perceived usefulness by the stakeholders involved; and adaptability, acceptability and proximity to the community. However, there are still a number of areas for improvement concerning logistical support (travel, communication, etc.), human resources, initial and ongoing training for community volunteers, access to the healthcare system for the populations concerned, particularly women, and the performance of microbiological tests and communication of their results. The long-term viability of this program, while desired by the vast majority of those involved, also remains dependent on the question of funding and, more generally, on strengthening the healthcare system to reinforce the capacity of local communities to anticipate and cope with future epidemics.

Abbreviations

CBS

Community-based surveillance

DHIS 2

District health information software

DRC

Democratic republic of the congo

EBS

Event-based surveillance

FRC

French red cross

HNS

Host national society

IDSR

Integrated disease surveillance and response

IFCR

International federation of the red cross

PPP

Pilot programmatic partnership

WHO

World health organization

Author contributions

D.A.M. and J.D designed the study, participated in the evaluation in Chad and Cameroon, analyzed the quantitatives and qualitatives data and wrote the article.D.B.S., S.F.M.C.H, I.C.A., H.Y. supervised CBS projects in Cameroon, Chad, Niger and the DRC respectively, and played an active role in collecting epidemiological quantitatives and qualitatives data.All authors consented to the publication of this paper and have read the final version.

Funding

This evaluation was funded by the French Red Cross. The CBS program was part of a larger regional program (Pilot Programmatic Partnership (PPP)) funded by the European Union (DG ECHO).

Data availability

Access to anonymous quantitative epidemiological and qualitative data (semi-structured interviews) is possible by contacting the authors at djeriamani.molamba@croix-rouge.fr.

Declarations

Ethics approval and consent to participate

The ethical principles associated with research were observed. All information that could lead to the identification of participants or suspected cases in database was removed. The CBS was set up and evaluated with the agreement of local authorities and the active participation of the Red Cross societies of Cameroon, Chad, Niger and DRC.Each participant interviewed received oral and written information, and written consent was obtained.

Consent for publication

All authors consented to the publication of this paper and have read the final version.

Competing interests

This evaluation was funded by the French Red Cross. The authors, as members of the French Red Cross, are salaried employees. No remuneration was specifically received by the authors for this publication.