Genetic variation among African swine fever genotype II viruses, eastern and central Europe

Abstract

African swine fever virus (ASFV) was first reported in eastern Europe/Eurasia in 2007. Continued spread of ASFV has placed central European countries at risk, and in 2014, ASFV was detected in Lithuania and Poland. Sequencing showed the isolates are identical to a 2013 ASFV from Belarus but differ from ASFV isolated in Georgia in 2007.

Figure 1

Locations of 4 cases of African swine fever in wild boars in the European Union countries of Poland and Lithuania and location of a 2013 outbreak among domestic pigs in Belarus, an eastern European country that shares a border with Poland and Lithuania. Inset map shows location (square) of countries in the larger map within the larger surrounding area.

Figure 2

Minimum evolution (ME) phylogenetic tree of African swine fever virus (ASFV) isolates from Lithuania and Poland based on the C-terminal end of the p72 coding gene relative to the 22 p72 genotypes (labeled I-XXII), including 88 nt sequences. The tree was inferred by using the ME method (http://www.megasoftware.net/mega4/WebHelp/part_iv___evolutionary_analysis/constructing_phylogenetic_trees/minimum_evolution_method/rh_minimum_evolution.htm) following initial application of a neighbor-joining algorithm. The phylogenetic tree was rooted by the midpoint method. The percentage of replicate trees >50% in which the associated taxa clustered together by bootstrap analysis (1,000 replicates) is shown adjacent to the nodes. The robustness of the ME tree was tested by using the close-neighbor-interchange algorithm at a search level of 1. Squares indicate ASFV isolates from Lithuania and Poland that were genotyped in this study; circles indicate ASFV isolates during 2007–2013 from the Caucasus region. Scale bar indicates nucleotide mutations per site.

Figure 3

Partial nucleotide sequence alignment of the intergenic region between I73R and I329L in African swine fever virus (ASFV) isolates from eastern and central Europe, including a virus isolated in 2007 in Georgia (Georgia2007; GenBank accession no. FR682468.1). The mutation that results in the insertion of a single nucleotide internal repeat sequence (GGAATATATA) in the ASFVs from Belarus, Ukraine, Lithuania, and Poland is indicated by gray shading.