We’re pleased to announce the launch of PLoS Currents: Influenza, a website for the rapid communication of research results and ideas vetted by expert moderators Eddie Holmes (Center for Disease Dynamics, Pennsylvania State University, USA) and Peter Palese (Department of Microbiology, Mount Sinai School of Medicine, USA). Here is a guest blog post from Eddie.
Harold Varmus has explained the exciting concept behind PLoS Currents: Influenza in his blog, so I will take this opportunity to briefly describe the content of the first set of contributions.
The central idea of PLoS Currents: Influenza is to rapidly disseminate data and ideas in the realm of influenza research, stimulated by the ongoing epidemic of swine-origin influenza virus (H1N1pdm). Given this backdrop, it is no surprise that some of first contributions consider important aspects of the H1N1pdm epidemic. Chowell and colleagues use mathematical models to explore how best to control H1N1pdm when the vaccine supply is limited. Their solution is an ‘adaptive’ vaccination policy, in which epidemiological data collected in real time are used to decide which age-group would benefit most from vaccination. Interestingly, in the case of H1N1pdm in Mexico, the optimum group to vaccinate are those aged between 6-59 years, whereas in seasonal influenza it is more usual to vaccinate those under the age of 5 or over 65.
Rambaut and Holmes use the rapidly growing data base of publicly available influenza virus genome sequences to investigate the molecular epidemiology and evolution of H1N1pdm. Their analysis reveals that the circulating strains of H1N1pdm share a common ancestor that originated during the first 7 weeks of 2009. This means that the virus may have been cryptically circulating for up to three months before it came to the attention of the health authorities in April 2009. This analysis also highlights how rapidly H1N1pdm has been able to spread globally, with multiple introductions into most countries. More generally, this contribution illustrates a key aspect of the PLoS Currents: Influenza ethos; that contributions can be short and present preliminary data.
Although PLoS Currents: Influenza was inspired by H1N1pdm, it will cover all types of research on all types of influenza virus. Indeed, the emergence of H1N1pdm brings into focus the need for basic research into many fundamental aspects of influenza biology. An example is provided by Lowen and Palese who tackle one of the most puzzling issues in influenza – its distinctive seasonality. As those of us who live in the northern (and southern) hemispheres are well aware, influenza is usually a winter disease. In the tropics, however, influenza has a far less marked seasonal incidence. Lowen and Palese suggest that climate plays a major role in establishing this pattern, such that the efficiency of viral transmission is set by a combination of temperature and humidity. They go on to propose that these climatic factors mean that influenza is most often transmitted by aerosols during the winter in temperate regions, but by direct contact in the tropics.
In a very different type of study, Cherry and colleagues investigate an important and little-studied aspect of the evolution of seasonal influenza virus – glycosylation. To address this issue they analyzed the distribution of N-linked asparagine glycosylation sites in the H3N2 virus that has dominated human influenza infections since 1968. Importantly, they show that there are major differences in the rate of gain and loss of glycosylation sites between the main ‘trunk’ branch – that links H3N2 viruses sampled from successive epidemics from 1968 to the present day – and the short ‘side’ branches that die-out in each season, with gains in the number of glycosylation sites dominating trunk evolution. This is interpreted to mean that there has been on-going selection for N-linked asparagine glycosylation.
These initial contributions have given PLoS Currents: Influenza an excellent start. The next few months should prove to be very exciting. I therefore encourage all of you working in the area of influenza to send a contribution to PLoS Currents: Influenza, however preliminary, so that your data and ideas are rapidly distributed to a wide audience.
Eddie Holmes, Chief Moderator, PLoS Currents: Influenza