Circulation of Two Distinct Phylogenetic Subclades of Rabies Viruses in Lao PDR

Rabies remains a significant public health concern in Lao People's Democratic Republic (Lao PDR), with domestic dogs serving as the primary reservoir host and transmission vector. Despite the endemic presence of rabies virus (RABV) within Lao PDR, molecular data on the current circulation of this virus within the country are limited.

In this study, we generated 94 new whole-genome sequences of animal RABV isolates collected between 2017 and 2023 in Lao PDR using the Nanopore technology. We then performed phylogenetic analyses by inferring maximum-likelihood trees on the five concatenated rabies genes and on nucleoprotein and glycoprotein genes.

Phylogenetic analyses revealed that the Lao isolates predominantly cluster in three endemic phylogenetic groups of the Southeast Asian 3 (SEA3) subclade within the Asian clade. Additionally, we report the detection of RABV isolates related to the SEA1b subclade in Lao PDR.

Our findings highlight the complex and dynamic patterns of RABV transmission, likely influenced by transboundary dog movement, and underscore the importance of continuous molecular surveillance at the regional and national levels.