Background: Ixodes ricinusis the most common tick species in Europe and the main vector forBorrelia burgdorferi(sensu lato) and tick-borne encephalitis virus (TBEV). It is involved also in the transmission ofBorrelia miyamotoi, a relapsing fever spirochete that causes health disorders in humans. Little is known regarding the circulation ofBorreliaspecies and the natural foci of TBEV in north-eastern Germany. The goal of this study was to investigate the infection rates ofBorreliaspp. and of TBEV inI. ricinusticks from north-eastern Germany.Methods: Ticks were collected by flagging from 14 forest sites in Mecklenburg-Western Pomerania between April and October 2018. RNA and DNA extraction was performed from individual adult ticks and from pools of 2–10 nymphs. Real time reverse transcription PCR (RT-qPCR) targeted the 3′ non-coding region of TBEV, while DNA ofBorreliaspp. was tested by nested PCR for the amplification of 16S-23S intergenic spacer. Multilocus sequence typing (MLST) was performed onB. miyamotoiisolates.Results: In total, 2407 ticks were collected (239 females, 232 males and 1936 nymphs). Female and maleI. ricinusticks had identical infection rates (both 12.1%) forBorreliaspp., while nymphal pools showed a minimum infection rate (MIR) of 3.3%. Sequencing revealed fourBorreliaspecies:B. afzelii,B. garinii,B. valaisianaandB. miyamotoi.Borrelia afzeliihad the highest prevalence in adult ticks (5.5%) and nymphs (MIR of 1.8%).Borrelia miyamotoiwas identified in 3.0% of adults and registered the MIR of 0.8% in nymphs.Borrelia valaisianawas confirmed in 2.5% adult ticks and nymphs had the MIR of 0.7%, whileB. gariniiwas present in 1.1% of adults and showed a MIR of 0.1% in nymphs. The MLST ofB. miyamotoiisolates showed that they belong to sequence type 635. No tick sample was positive after RT-qPCR for TBEV RNA.Conclusions: The prevalence ofB. miyamotoiinI. ricinusticks registered similar levels to other reports from Europe suggesting that this agent might be well established in the local tick population. The detection ofB. burgdorferi(s.l.) indicates a constant circulation in tick populations from this region.

African swine fever virus (ASFV), causing an OIE-notifiable viral disease of swine, is spreading over the Eurasian continent and threatening the global pig industry. Here, we conducted the first proteome analysis of ASFV-infected primary porcine monocyte-derived macrophages (moMΦ). In parallel to moMΦ isolated from different pigs, the stable porcine cell line WSL-R was infected with a recombinant of ASFV genotype IX strain “Kenya1033”. The outcome of the infections was compared via quantitative mass spectrometry (MS)-based proteome analysis. Major differences with respect to the expression of viral proteins or the host cell response were not observed. However, cell-specific expression of some individual viral proteins did occur. The observed modulations of the host proteome were mainly related to cell characteristics and function. Overall, we conclude that both infection models are suitable for use in the study of ASFV infection in vitro.

Since the introduction of a highly pathogenic genotype II isolate of the African swine fever virus (ASFV) into Georgia in 2007, African swine fever (ASF) has gone panzootic. Outbreaks have been reported in Europe, Asia and, more recently, Latin America. Thus, ASFV has become a major threat to the pig industry worldwide, as broadly applicable vaccines are not available. While the majority of ASFV strains show high virulence in domestic pigs and wild boar, variations within the ASFV genome have resulted in the emergence of attenuated strains with low or moderate virulence. However, the molecular basis of the differences in virulence has not yet been discovered. To reveal virulence-associated protein expression patterns, we analysed the proteomes of the natural target cells of ASFV, primary porcine macrophages, after infection with two genotype II ASFV strains displaying high (Armenia 2008) and moderate (Estonia 2014) virulence using quantitative mass spectrometry. Very similar expression patterns were observed for the viral genes, and any differences were limited to the deletions within the Estonia 2014 genome. In addition to the canonical ASFV proteins, twelve novel protein products from recently described transcripts were confirmed in both isolates. Pathway analyses showed that both isolates evoked a similar host proteome response, despite their difference in virulence. However, subtle differences in the manipulation of the proteins involved in the proinflammatory response mediated by the MAPK14/p38 signalling cascade were observed

African swine fever is a viral disease of swine caused by the African swine fever virus (ASFV). Currently, ASFV is spreading over the Eurasian continent and threatening global pig husbandry. One viral strategy to undermine an efficient host cell response is to establish a global shutoff of host protein synthesis. This shutoff has been observed in ASFV-infected cultured cells using two-dimensional electrophoresis combined with metabolic radioactive labeling. However, it remained unclear if this shutoff was selective for certain host proteins. Here, we characterized ASFV-induced shutoff in porcine macrophages by measurement of relative protein synthesis rates using a mass spectrometric approach based on stable isotope labeling with amino acids in cell culture (SILAC). The impact of ASFV infection on the synthesis of >2000 individual host proteins showed a high degree of variability, ranging from complete shutoff to a strong induction of proteins that are absent from naïve cells. GO-term enrichment analysis revealed that the most effective shutoff was observed for proteins related to RNA metabolism, while typical representatives of the innate immune system were strongly induced after infection. This experimental setup is suitable to quantify a virion-induced host shutoff (vhs) after infection with different viruses.