ADVANCING RABIES DIAGNOSIS: A SYSTEMATIC REVIEW AND META-ANALYSIS COMPARING MOLECULAR AND CONVENTIONAL METHODS FOR DIAGNOSTIC ACCURACY AND EARLY DETECTION IN HUMANS

Abstract

Background: Rabies remains a universally fatal zoonotic disease once clinical symptoms appear, accounting for significant mortality in low- and middle-income countries. Early and accurate diagnosis is crucial for patient management, surveillance, and implementation of public health measures. Conventional diagnostic methods such as Direct Fluorescent Antibody (DFA) testing are considered gold standards but are largely limited to postmortem confirmation. In contrast, molecular diagnostic techniques have emerged as promising tools for early and antemortem detection. This systematic review and meta-analysis aimed to compare the diagnostic accuracy of molecular and conventional methods for human rabies.

Methods: A comprehensive literature search was conducted across PubMed, Scopus, Web of Science, and Embase for studies published between 1990 and 2026. Studies evaluating diagnostic methods for human rabies with reported sensitivity and specificity were included. Data extraction and quality assessment were performed using standardized tools, including the QUADAS-2 framework. Meta-analysis was conducted using a random-effects model to calculate pooled sensitivity, specificity, likelihood ratios, and diagnostic odds ratios. Summary Receiver Operating Characteristic (SROC) curves were constructed to evaluate overall diagnostic performance.

Results: A total of 60 studies were included in the qualitative synthesis, with 48 studies eligible for meta-analysis. Molecular diagnostic methods demonstrated higher pooled sensitivity (92.3%; 95% CI: 88.7–95.1%) compared to conventional methods (85.4%; 95% CI: 80.2–89.7%), while maintaining comparable specificity (96.5% vs. 98.8%). Real-time PCR exhibited the highest diagnostic accuracy among molecular techniques. Nuchal skin biopsy samples showed superior sensitivity compared to saliva and cerebrospinal fluid. Conventional methods, particularly DFA, remained highly specific but were limited by their dependence on postmortem samples. SROC analysis revealed a higher area under the curve for molecular methods (AUC = 0.97) compared to conventional methods (AUC = 0.91).

Conclusion: Molecular diagnostic methods significantly outperform conventional techniques in terms of sensitivity and enable early antemortem detection of rabies. While conventional methods remain valuable for confirmatory diagnosis and surveillance, integration of molecular tools into routine diagnostic workflows is essential for improving clinical outcomes and strengthening rabies control programs. These findings support global efforts, including those led by the World Health Organization, toward the elimination of rabies.