Spatial Temporal Dynamics and Molecular Evolution of Re-Emerging Rabies Virus in Taiwan

Abstract

Taiwan has been recognized by the World Organization for Animal Health as rabies-free since 1961. Surprisingly, rabies virus (RABV) was identified in a dead Formosan ferret badger in July 2013. Later, more infected ferret badgers were reported from different geographic regions of Taiwan. In order to know its evolutionary history and spatial temporal dynamics of this virus, phylogeny was reconstructed by maximum likelihood and Bayesian methods based on the full-length of glycoprotein (G), matrix protein (M), and nucleoprotein (N) genes. The evolutionary rates and phylogeographic were determined using Beast and SPREAD software. Phylogenetic trees showed a monophyletic group containing all of RABV isolates from Taiwan and it further separated into three sub-groups. The estimated nucleotide substitution rates of G, M, and N genes were between 2.49ˆ10´4-4.75ˆ10´4 substitutions/site/year, and the mean ratio of dN/dS was significantly low. The time of the most recent common ancestor was estimated around 75, 89, and 170 years, respectively. Phylogeographic analysis suggested the origin of the epidemic could be in Eastern Taiwan, then the Formosan ferret badger moved across the Central Range of Taiwan to western regions and separated into two branches. In this study, we illustrated the evolution history and phylogeographic of RABV in Formosan ferret badgers.

The history of rabies in the Western Hemisphere

“…Although these figures pale in comparison to the number of human infections by dog-maintained RABLV lineages, it is clear that bat-associated rabies is also affecting vulnerable human populations and their domestic animals. Furthermore, these data reflect the increasing frequency of interaction between domestic animals (especially dogs), bats and terrestrial wildlife under the current and evolving status of human demographics and culture ( Escobar et al, 2015 ; Harcourt, 2016 ; Lin et al, 2016 ; Liu et al, 2010 ; Yung et al, 2012 ). At the same time, several Latin American countries (Argentina, Brazil, Chile, Colombia, Ecuador, Paraguay, Peru, Uruguay) with highly successful programs for the control and elimination of dog-maintained rabies have weakened or suspended canine vaccination programs, resulting in increasing numbers of rabies-susceptible dogs and cats ( Escobar et al, 2015 ; Velasco-Villa et al, 2017 in press ).…”

“…Modern ancestral reconstruction methods have become instrumental in estimating an approximate date for the emergence of most dog-derived RABLV variants around the world ( Hanke et al, 2016 ; Hughes et al, 2005 ; Lin et al, 2016 ). Estimated dates based on sequence data (phylogenetic methods) are often more recent than the first historical records, which may be due to assumptions built into molecular clock analyses (e.g., viral isolation dates, taxonomic sampling, sampling distributions of calibration nodes), loss of historical data (viral isolates or documentation either not kept or lost due to unusual circumstances) or cryptic circulation of RABLV in sylvatic animals.…”

Using phylogeographic approaches to analyse the dispersal history, velocity and direction of viral lineages — Application to rabies virus spread in Iran

“…Taiwan (Lin et al, 2016) or more recently in Turkey (Marston et al, 2017;McElhinney et al, 2011). Understanding the key sources responsible for rabies epizootics and identifying host switches can have concrete implications on the implementation of rabies control measures in animals, as well as on the strategy of animal vaccination towards the ultimate goal of elimination (Fusaro et al, 2013;Un et al, 2012).…”

Gut Microbiota Contribute to Age-Related Changes in Skeletal Muscle Size, Composition, and Function: Biological Basis for a Gut-Muscle Axis

“…Given the corresponding change in diet (i.e., low in plant-based nutrients and fiber and high in sucrose and saturated fat) and microbial composition when individuals enter long-term care facilities [99], geriatric clinicians are encouraged to work with older individuals undergoing residence relocation to pursue nutritional strategies that aim to prevent the loss of healthy microbes (e.g., butyrate-producing bacteria). Relevantly, prebiotic supplementation (inulin plus fructooligosaccharides) has been shown to increase muscle strength (handgrip) and endurance (exhaustion) in frail older adults [100], thereby highlighting the utility of prebiotic supplementation as a treatment for age-associated deficits in muscle function.…”