RESUMEN
Canine distemper virus (CDV) is a lethal viral disease of carnivores which is considered to be a serious threat to domestic and wild species. Despite the widespread use of vaccines, CDV still occurs in vaccinated animals and current vaccines does not guarantee complete protection. In this study, a total of 286 hemagglutinin (H) gene sequences of the virus isolated in 25 countries during 90 years (1930-2020) were analyzed by Bayesian maximum likelihood analysis to estimate the population dynamics. We identified the most recent common ancestor (TMRCA) of the virus in 1868 in the USA which arrived in continental Europe in 1948, and from there, the virus spread rapidly to other continents. The Canidae family was identified as the original host as well as a source of the subsequent spread. We identified 11 lineages of geographic co-circulating strains globally. The effective population size experienced a two-phase-exponential growth between 2000-2005 and 2010-2012. Our findings provide a novel insight into the epidemic history of canine distemper virus which may facilitate more effective disease management. This study uses a large set of sequencing data on the H gene of CDV to identify distinct lineages of the virus, track its geographic spread over time, analyze its likelihood of transmission within and between animal families, and provide suggestions for improved strategies to combat the virus. Supplementary Information: The online version contains supplementary material available at 10.1007/s10344-023-01685-z.
RESUMEN
China has experienced a sudden multi-focal and multi-round of African swine fever (ASF) outbreaks during 2018. The subsequent epidemiological survey resulted in a debate including the possibility of a transboundary spread from European Russia to China through wild boar. We contribute to the debate by assessing a hypothetical overland Euro-Siberian transmission path and its associated ASF arrival dates. We selected the maximum entropy algorithm for spatial modelling of ASF-infected wild boar and the Spatial Distribution Modeller in ArcGIS to plot Least Cost Paths (LCPs) between Eastern Europe and NE China. The arrival dates of ASF-infected wild boar have been predicted by cumulative maximum transmission distances per season and cover with their associated minimum time intervals along the LCPs. Our results show high costs for wild boar to cross Kazakhstan, Xinjiang (NW China) and/or Mongolia to reach NE China. Instead, the Paths lead almost straight eastward along the 59.5° northern latitude through Siberia and would have taken a minimum of 219 or 260 days. Therefore, infected wild boar moving all the way along the LCP could not have been the source of the ASF infection in NE China on 2 August 2018.
