Virology News

Hybrid viruses derived from an H5N1 bird flu strain can infect guinea pigs through the air.

Human influenza infections exhibit a strong seasonal cycle in temperate regions. Recent laboratory and epidemiological evidence suggests that low specific humidity conditions facilitate the airborne survival and transmission of the influenza virus in temperate regions, resulting in annual winter epidemics. However, this relationship is unlikely to account for the epidemiology of influenza in tropical and subtropical regions where epidemics often occur during the rainy season or transmit year-round without a well-defined season. We assessed the role of specific humidity and other local climatic variables on influenza virus seasonality by modeling epidemiological and climatic information from 78 study sites sampled globally. We substantiated that there are two types of environmental conditions associated with seasonal influenza epidemics: “cold-dry” and “humid-rainy”. For sites where monthly average specific humidity or temperature decreases below thresholds of approximately 11–12 g/kg and 18–21°C during the year, influenza activity peaks during the cold-dry season (i.e., winter) when specific humidity and temperature are at minimal levels. For sites where specific humidity and temperature do not decrease below these thresholds, seasonal influenza activity is more likely to peak in months when average precipitation totals are maximal and greater than 150 mm per month. These findings provide a simple climate-based model rooted in empirical data that accounts for the diversity of seasonal influenza patterns observed across temperate, subtropical and tropical climates.

NIAID scientists and their collaborators travel to a remote village in the Republic of the Congo to search for Ebola

and other emerging viruses.

Vaccination has been successful at controlling many of the world’s diseases. However, there are many emerging viral diseases for which no licensed (US or EU) vaccine exists. Here I’ve selected 10 emerging or re-emerging viruses which I think are especially important due to their incidence, prevalence, morbidity, mortality and suitability of current treatment...

Ebola virus graphic courtesy of Russell Kightely Media