Equid herpesvirus type 1 (EHV-1) disrupt actin cytoskeleton during productive infection in equine leukocytes

Equid herpesvirus type 1 (EHV-1) is a prevalent causative agent of equine diseases worldwide. After primary replication in the respiratory epithelium the virus disseminates systemically through a peripheral blood mononuclear cell (PBMC)-associated viraemia. EHV-1 is the only alphaherpes-virus known so far which is capable of establishing latent infection not only in neurons but also in immune system cells (mainly in lymphocytes and macrophages). Since leukocytes are not the target cells for viral replication but are used to transport EHV-1 to the internal organs, the question remains how the virus avoids the immune response and whether it could potentially be associated with virus-induced cytoskeletal rearrangements. Therefore, the aim of this study was to investigate the progress of EHV-1 replication in leukocytes stimulated by phytohemagglutinin and the impact of EHV-1 infection on the actin cytoskeleton. Using the real-time PCR method we evaluated the quantity of viral DNA from samples collected at indicated time points post infection. In order to examine possible changes in actin cytoskeleton organization due to EHV-1 infection, we performed immunofluorescent staining using TRITC-phalloidin conjugate. The results showed that EHV-1 replicates in leukocytes at a restricted level but with the accompaniment of chromatin degradation. Simultaneously, infection with EHV-1 caused disruption of the actin cytoskeleton; this was particularly apparent in further stages of infection. Disruption of the actin cytoskeleton may lead to the limited release of the virus from the cells, but may be also beneficial for the virus, since at the same time it potentially impairs the immune function of leukocytes

Recombination Resulting in Virulence Shift in Avian Influenza Outbreak, Chile

Influenza A viruses occur worldwide in wild birds and are occasionally associated with outbreaks in commercial chickens and turkeys. However, avian influenza viruses have not been isolated from wild birds or poultry in South America. A recent outbreak in chickens of H7N3 low pathogenic avian influenza (LPAI) occurred in Chile. One month later, after a sudden increase in deaths, H7N3 highly pathogenic avian influenza (HPAI) virus was isolated. Sequence analysis of all eight genes of the LPAI virus and the HPAI viruses showed minor differences between the viruses except at the hemagglutinin (HA) cleavage site. The LPAI virus had a cleavage site similar to other low pathogenic H7 viruses, but the HPAI isolates had a 30 nucleotide insert. The insertion likely occurred by recombination between the HA and nucleoprotein genes of the LPAI virus, resulting in a virulence shift. Sequence comparison of all eight gene segments showed the Chilean viruses were also distinct from all other avian influenza viruses and represent a distinct South American clade

Species and abundance of ectoparasitic flies (Diptera) in pied flycatcher nests in Fennoscandia

Peer reviewe

Interaction of climate change with effects of conspecific and heterospecific density on reproduction

We studied the relationship between temperature and the coexistence of great titParus majorand blue titCyanistes caeruleus, breeding in 75 study plots across Europe and North Africa. We expected an advance in laying date and a reduction in clutch size during warmer springs as a general response to climate warming and a delay in laying date and a reduction in clutch size during warmer winters due to density-dependent effects. As expected, as spring temperature increases laying date advances and as winter temperature increases clutch size is reduced in both species. Density of great tit affected the relationship between winter temperature and laying date in great and blue tit. Specifically, as density of great tit increased and temperature in winter increased both species started to reproduce later. Density of blue tit affected the relationship between spring temperature and blue and great tit laying date. Thus, both species start to reproduce earlier with increasing spring temperature as density of blue tit increases, which was not an expected outcome, since we expected that increasing spring temperature should advance laying date, while increasing density should delay it cancelling each other out. Climate warming and its interaction with density affects clutch size of great tits but not of blue tits. As predicted, great tit clutch size is reduced more with density of blue tits as temperature in winter increases. The relationship between spring temperature and density on clutch size of great tits depends on whether the increase is in density of great tit or blue tit. Therefore, an increase in temperature negatively affected the coexistence of blue and great tits differently in both species. Thus, blue tit clutch size was unaffected by the interaction effect of density with temperature, while great tit clutch size was affected in multiple ways by these interactions terms.Peer reviewe