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Botvinkin et al. One Health Implement Res 2023;3:125-34 https://dx.doi.org/10.20517/ohir.2023.19 Page 131

Figure 3. Spatial distribution of documented animal rabies cases in the Amur River basin. (1) lineage was not determined; (2) Arctic-like
2 isolates; (3) Steppe isolates. Russian Far East: ARR - 2018-2022; TBR - 2014-2020 [after 21] ; JAR - 2017-2019; KHR - 2018-2019; PRR:
adjacent territories of China (2007-2018) [after 16-19] ; (4) detection of Arctic-like 2 isolates in Russia in 1977-
1989 [after 14, the locations were corrected according to original information about the samples collection] . Black lines: state and regional borders; Arrows: probable
directions of rabies virus incursion into ARR. ARR: Amur Region; JAR: Jewish Autonomous Region; KHR: Khabarovsk Region; PRR:
Primorsky Region; TBR: Trans-Baikal Region.

the Steppe lineage prevails. Currently, foxes play a pivotal role in the spread of rabies in the IMAR and some
other provinces in northern China [5,18,25] .

Because of the data collected, two scenarios of RABV incursion into the ARR were suggested. It is most
likely that rabies was introduced by wild carnivores from a natural focus located in the middle reaches of the
Amur River. Mountain ranges sandwich the narrow valley of the Amur River in a section about 150 km
long between the Zeya-Bureya and the Middle Amur Plains. The border between Russia and China lies
along the Amur River. Due to the border protection, the floodplain territory, island, and coastal biotopes are
little used for economic needs in both countries. The absence of anthropogenic press creates ample
opportunities for wildlife, including migrations of carnivores along frozen rivers in winter, and may
contribute to the transboundary spread of RABV. Another possible incursion route might occur from the
Central Manchurian Plain along the valleys of the right-bank tributaries that flow into the Amur River near
the site of the first reported ARR rabies case in 2018 [Figure 3]. However, in available publications, we could
not find reports with georeferencing of rabies cases in the bordering area of China.

A retrospective analysis of the outbreak of rabies in the ARR demonstrates the importance of ecological
channels and natural barriers for the spread of wildlife rabies. Presumably, the relative geographical
isolation of the Zeya-Bureya Plain contributed to the conservation of the rabies-free status of the ARR for a
long time. The Zeya-Bureya Plain is separated from similar landscapes in Russia and China by mountain
ranges covered with taiga and coniferous-broad-leaved forests (dark green shading on the maps, Figures 1
and 3). The concentration of rabies cases along river valleys and at the junctions of forest and open
landscapes is remarkable on this map. The habitats of mesocarnivores in the river floodplains and foothills
are preserved even in conditions of intensive use of the plains for crops. It should be emphasized that rabies