National Borders Effectively Halt the Spread of Rabies: The Current Rabies Epidemic in China Is Dislocated from Cases in Neighboring Countries

Abstract

China has seen a massive resurgence of rabies cases in the last 15 years with more than 25,000 human fatalities. Initial cases were reported in the southwest but are now reported in almost every province. There have been several phylogenetic investigations into the origin and spread of the virus within China but few reports investigating the impact of the epidemic on neighboring countries. We therefore collected nucleoprotein sequences from China and South East Asia and investigated their phylogenetic and phylogeographic relationship. Our results indicate that within South East Asia, isolates mainly cluster according to their geographic origin. We found evidence of sporadic exchange of strains between neighboring countries, but it appears that the major strain responsible for the current Chinese epidemic has not been exported. This suggests that national geographical boundaries and border controls are effective at halting the spread of rabies from China into adjacent regions. We further investigated the geographic structure of Chinese sequences and found that the current epidemic is dominated by variant strains that were likely present at low levels in previous domestic epidemics. We also identified epidemiological linkages between high incidence provinces consistent with observations based on surveillance data from human rabies cases.

Molecular Phylodynamic Analysis Indicates Lineage Displacement Occurred in Chinese Rabies Epidemics between 1949 to 2010

“…The primary exception to this pattern is the isolation of samples from the low case region of Neimenggu (Inner Mongolia) that are placed in the China IV/Arctic-like clade. This suggests that this lineage plays a minor role in the epidemic, further supported by our recently published results investigating the relationship amongst China rabies and lineages in neighbouring countries [31].…”

“…To investigate the contribution from wildlife to rabies in China, wildlife and domestic sequences from the dataset above were combined with the dataset generated from our earlier study based on the N gene to generate a dataset of 368 samples [31]. A complete list of the wildlife isolates are given in Table S4.…”

Large-Scale Phylogenomic Analysis Reveals the Complex Evolutionary History of Rabies Virus in Multiple Carnivore Hosts

“…a molecular clock) was observed within the dog-related RABV group, with a mean evolutionary rate of 2.44 x 10 −4 subs/site/year (95% HPDs of 2.10–2.80 x 10 −4 subs/site/year) for the five concatenated genes. This estimate is evidently more precise than those determined previously [13, 25, 27, 30, 44, 50–53]. …”

Cross-border spread, lineage displacement and evolutionary rate estimation of rabies virus in Yunnan Province, China

“…1) [7, 8, 11, 13]. The geographic locations of the different clusters of Asian RABV, SEA-1–3, are shown in Fig.…”