Establishing the basis for rabies control and elimination in Liberia

Background: Rabies is a fatal zoonotic disease. Every year, an estimated 59'000 rabies-related deaths are reported globally, affecting four out of ten children. In endemic regions, domestic dogs are the main reservoir of rabies, transmitting the disease to humans through the bite or scratch of an infected animal. Although rabies in animals and humans is notifiable in Liberia, surveillance is primarily passive. There are no accurate estimates of the "true" rabies situation in the country. Based on these shortcomings and the global drive to end dog-related human rabies deaths by 2030, this Ph.D. work aimed to establish animal rabies diagnostics and gather relevant baseline information that is crucial for control programs for rabies elimination in Liberia.
Objectives: This PhD thesis achieved the following objectives, i) established animal rabies diagnostics at the Central Veterinary Laboratory, ii) surveyed the community's knowledge about rabies and vaccination scenarios, and iii) investigated molecular and phylogenetic characteristics of circulating rabies strains in Liberia.
Methods: We used a One Health approach, collaborating between key national and international rabies stakeholders, to successfully establish three animal rabies diagnostic tests. We used an opportunistic sampling approach to collect and diagnose the first animal rabies strain in post-war Liberia. A randomized cross-sectional knowledge, attitude, and practice (KAP) household survey related to dog rabies and was used to estimate the dog population survey in rural and urban households. Based on this data, we developed three scenarios for mass dog vaccination. In addition, we strengthened the rabies surveillance system to collect suspected animal rabies samples to perform a genome-based phylogenetic analysis of RABV isolates circulating in Liberia.
Results: Analyses of the first rabies samples revealed that all isolates belonged to the Africa 2 lineage; Subgroup H circulates in the domestic dog population. This finding subsequently flagged Liberia as an endemic rabies country. It contributed, among other factors, to the country’s score of 1.5/5 on the Stepwise Approach towards Rabies Elimination (SARE) tool, indicating that Liberia is in the early stages of dog rabies control. Results from the cross-sectional survey conducted in rural and urban households estimated a mass vaccination cost of USD 1.5 – 1.6 million to vaccinate the total dog population for one vaccination round. Rabies knowledge among participants was low, thus influencing risky practices. Results from strengthening rabies surveillance identified the disease hotspots. It further demonstrated that RABV isolates circulating in Liberia were clustered into the phylogroup H within the Africa 2 clade. This information is necessary for future rabies control and eradication programs.
Conclusion: This PhD work generated relevant information for rabies control in Liberia. Baseline information is crucial for effective rabies control. Our findings obtained from the household survey are important for developing a national rabies control strategy and intervention. At the same time, findings from the molecular and phylogenetic study are vital to developing appropriate vaccination strategies for dogs and allow their effectiveness to be assessed in Liberia.