In this week's Nature, a team of Chinese researchers report on discovering new variation in the genome of the strain of Ebola virus responsible for the outbreak in Sierra Leone since it was first introduced to the region. The researchers analyzed 175 Ebola virus genome sequences collected from five distinct regions in the country between September and November 2014 after a rapid growth of the outbreak. They found that the genetic diversity of the virus has increased substantially, with several new lineages emerging.
Meanwhile, in Nature Communications, University of Cambridge scientists present data showing how human gene expression changes with the seasons, offering clues to why certain infectious and chronic diseases display seasonal patterns. By analyzing genetic data from publicly available datasets, the group found that roughly a quarter of all genes display significant seasonal differences in expression and that the relative composition of different immune cells in the blood changes with seasons as well. For instance, the European winter pattern is pro-inflammatory with higher levels of cardiovascular and autoimmune disease-linked proteins in blood. In West Africa, people display a peak in seasonal cell types between June and October when rains set in and diseases like malaria become more prevalent. The findings, the study's authors say, could help direct vaccination programs so that they are undertaken when they will be most effective. GenomeWeb has more on this study here.
Also in Nature Communications, a group led by Broad Institute investigators report on a genomic and transcriptomic study of host adaptation in two microsporidian pathogens, the specialist Edhazardia aedis and the generalist Vavraia culicis, both transmitted by mosquitos. Both are obligate intracellular pathogens, needing nutrients and metabolites from their hosts, but also need to evade host defenses. Genome and RNA-seq analysis reveals fundamental differences in cell surface modification and secretion, metabolic capacity, ability to splice transcripts, and host-pathogen transcriptional interplay during infection, the researchers report. The findings further reveal the fundamentally different evolutionary paths and host interplay of specialist and generalist pathogens.