Abstract
African swine fever (ASF) has spread across many countries in Europe
since the introduction into Georgia in 2007. We report here on the first
cases of ASF in wild boar detected in Germany close to the border with
Poland. In addition to the constant risk of ASF virus (ASFV) spread
through human activities, movements of infected wild boar also represent
a route of introduction. Since ASF emerged in Western Poland in November
2019, surveillance efforts, in particular examination of wild boar found
dead, were intensified in the regions of Germany bordering with Poland.
The first case of ASF in wild boar in Germany was therefore detected by
passive surveillance and confirmed on 10th September 2020. By 24th
September 2020, 32 cases were recorded. Testing of samples from tissues
of carcasses in different stages of decomposition yielded cycle
threshold values from 18 to 36 in the OIE-recommended PCR which were
comparable between the regional and national reference laboratory. Blood
swabs yielded reliable results, indicating that the method is suitable
also under outbreak conditions. Phylogenetic analysis of the ASFV
whole-genome sequence generated from material of the first carcass
detected in Germany, revealed that it groups with ASFV genotype II
including all sequences from Eastern Europe, Asia and Belgium. However,
some genetic markers including a 14 bp tandem repeat duplication in the
O174L gene were confirmed that have so far been detected only in
sequences from Poland (including Western Poland). Epidemiological
investigations that include estimated postmortem intervals of wild boar
carcasses of infected animals suggest that ASFV had been introduced into
Germany in the first half of July 2020 or even earlier.