Search

Over the last three decades, the control of Beet necrotic yellow vein virus (BNYVV) in sugar beet has relied on the cultivation of varieties harbouring the Rz1 resistance gene. The strong selection pressure on BNYVV has favoured the development of resistance‐breaking strains that display mutations at amino acid positions 67–70 (tetrad) in the pathogenicity factor P25 and strains possessing an additional RNA component (RNA5). To evaluate the durability of Rz1 resistance, it is essential to monitor the ongoing virulence development in BNYVV populations. Therefore, we characterized BNYVV populations from different fields in Europe suspected to possess resistance‐breaking properties. The ability to overcome Rz1 resistance could be confirmed for several populations in greenhouse bait plant tests using susceptible and resistant genotypes. These populations were able to accumulate similar virus concentrations in both genotypes. Most of the populations harboured multiple P25 tetrad variants, but there was no obvious effect of the sugar beet genotype on their composition. The strong selection pressure on P25 was reflected by the overall high number of P25 haplotypes with several amino acids under positive selection. Two different RNA5 species closely related to either the French or the Asian RNA5 type were additionally identified in some populations. Finally, high‐throughput sequencing revealed the formation of genetic reassortments between different virus types, but the overall sequence diversity within BNYVV populations was relatively low and not affected by the genotype. Our results highlight the ongoing adaption of BNYVV towards Rz1 resistance, stressing the importance of alternative resistance sources. [ABSTRACT FROM AUTHOR]

Objectives To identify trends and patterns of sales of veterinary antimicrobial agents in nine European countries during 2005–09 in order to document the situation. Methods Existing sales data, in tonnes of active ingredients, of veterinary antimicrobial agents by class were collected from nine European countries in a standardized manner for the years 2005–09 (one country for 2006–09). A population correction unit (PCU) is introduced as a proxy for the animal population potentially treated with antimicrobial agents. The sales data are expressed as mg of active substance/PCU. Results Data coverage was reported to be 98%–100% for the nine countries. Overall, sales of veterinary antimicrobials agents, in mg/PCU, declined during the reporting period in the nine countries. Substantial differences in the sales patterns and in the magnitude of sales of veterinary antimicrobial agents, expressed as mg/PCU, between the nine countries are observed. The major classes sold were penicillins, sulphonamides and tetracyclines. The sales accounted for by the various veterinary antimicrobial agents have changed substantially for most countries. An increase in the sales of third- and fourth-generation cephalosporins and fluoroquinolones were observed for the majority of the countries. Conclusions Through re-analysis of existing data by application of a harmonized approach, an overall picture of the trends in the sales of veterinary antimicrobial agents in the nine countries was obtained. Notable differences in trends in sales between the countries were observed. Further studies, preferably including data by animal species, are needed to understand the factors that explain these observations. [ABSTRACT FROM AUTHOR]

H1N1 influenza A virus is a respiratory pathogen that undergoes antigenic shift and antigenic drift to improve viral fitness. Tracking the evolutionary trends of H1N1 aids with the current detection and the future response to new viral strains as they emerge. Here, we characterize antigenic drift events observed in the hemagglutinin (HA) sequence of the pandemic H1N1 lineage from 2015-2019. We observed the substitutions S200P, K147N, and P154S, together with other mutations in structural, functional, and/or epitope regions in 2015-2019 HA protein sequences from the Mountain West region of the United States, the larger United States, Europe, and other Northern Hemisphere countries. We reconstructed multiple phylogenetic trees to track the relationships and spread of these mutations and tested for evidence of selection pressure on HA. We found that the prevalence of amino acid substitutions at positions 147, 154, 159, 200, and 233 significantly changed throughout the studied geographical regions between 2015 and 2019. We also found evidence of coevolution among a subset of these amino acid substitutions. The results from this study could be relevant for future epidemiological tracking and vaccine prediction efforts. Similar analyses in the future could identify additional sequence changes that could affect the pathogenicity and/or infectivity of this virus in its human host.

Atypical porcine pestivirus (APPV) has been identified as the main causative agent for congenital tremor (CT) type A-II in piglets, which is threatening the health of the global swine herd. However, the evolution of APPV remains largely unknown. In this study, phylogenetic analysis showed that APPV could be divided into three phylogroups (I, II, and III). Phylogroups I and II included viral strains from China, while phylogroup III contained strains from Europe, North America, and Asia. Phylogroups I and II are tentatively thought to be of Chinese origin. Next, compositional property analysis revealed that a high frequency of nucleotide A and A-end codons was used in the APPV genome. Intriguingly, the analysis of preferred codons revealed that the AGA[Arg] and AGG[Arg] were overrepresented. Dinucleotide CC was found to be overrepresented, and dinucleotide CG was underrepresented. Furthermore, it was found that the weak codon usage bias of APPV was mainly dominated by selection pressures versus mutational forces. The codon adaptation index (CAI), relative codon deoptimization index (RCDI), and similarity index (SiD) analyses showed that the codon usage patterns of phylogroup II and III were more similar to the one of a pig than phylogroup I, suggesting that phylogroup II and III may be more adaptive to pigs. Overall, this study provides insights into APPV evolution through phylogeny and codon usage pattern analysis.

Objectives: To describe sales and sales patterns of veterinary antimicrobial agents in 25 European Union (EU)/European Economic Area (EEA) countries for 2011., Methods: Data on the sales of veterinary antimicrobial agents from 25 EU member states and EEA countries for 2011 were collected at package level (name, formulation, strength, pack size, number of packages sold) according to a standardized protocol and template and presented in a harmonized manner. These data were calculated to express amounts sold, in metric tonnes, of active ingredient of each package. A population correction unit (PCU) was applied as a proxy for the animal biomass potentially treated with antimicrobial agents. The indicator used to express sales was milligrams of active substance per PCU., Results: Substantial variations in the sales patterns and in the magnitude of sales of veterinary antimicrobial agents, expressed as mg/PCU, between the countries were observed. The proportion of sales, in mg/PCU, of products applicable for treatment of groups or herds of animals (premixes, oral powders and oral solution) varied considerably between the countries., Conclusions: Some countries reported much lower sales of veterinary antimicrobial agents than others, when expressed as mg/PCU. Sales patterns varied between countries, particularly with respect to pharmaceutical forms. Further studies are needed to understand the factors that explain the observed differences., (© The Author 2014. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.)