Where are rabies cases lost along the surveillance pathway? A comparative evaluation of participatory and passive rabies surveillance in urban Lilongwe, Malawi

Abstract Background Rabies remains under-ascertained in many endemic settings, from limited effective surveillance and timely public health interventions, particularly in low-resource countries. Participatory surveillance has the potential to improve case detection, but evidence of its effect on surveillance attrition, case ascertainment, and public health decision-making remains limited. We evaluated a participatory rabies surveillance programme implemented in urban Lilongwe, Malawi, during a six-month pilot (January–June 2020). Methods Programme records from the pilot were retrospectively analysed. Surveillance progression was tracked from reporting through traceability assessment, investigation, and final case classification. Case retention, case ascertainment, and diagnostic yield were compared between participatory and passive surveillance pathways. Historical rabies diagnostic records from corresponding January–June periods during 2015–2019 served as a comparator. Results Of 610 suspected rabies reports, 393 (64.4%) were lost before traceability could be established. Of the 217 traceable reports, a further 67 (30.9%) did not progress from traceability assessment to investigation and final classification. Overall, only 150 reports (24.6%) completed the surveillance pathway. Participatory surveillance retained all reports through classification compared with 104 of 564 (18.4%) passive reports ( p < 0.001). Among classified events, confirmed or probable rabies accounted for 13 of 46 (28.3%) participatory reports compared with 7 of 104 (6.7%) passive reports (OR 5.39, 95% CI 1.82–17.39; p = 0.001). Participatory surveillance identified 13 of 20 (65.0%) confirmed or probable rabies cases, including all nine laboratory-confirmed cases detected during the study period. Compared with historical routine surveillance, participatory surveillance was associated with a 2.4-fold increase in laboratory-confirmed rabies detection and a 4.8-fold increase in overall case ascertainment. Among investigated bite exposures, 136 of 141 (96.5%) initiated post-exposure prophylaxis (PEP), although only 16 (11.8%) were linked to confirmed or probable rabies exposures. Conclusion Rabies cases were lost predominantly between initial reporting and traceability assessment, with further attrition before investigation and final classification. Participatory surveillance reduced surveillance losses, improved case ascertainment, and generated more timely animal health evidence to support One Health public health decision-making, including more appropriate PEP use.