Jan 14, 2013
H5N1 hits backyard flocks in Bhutan
An outbreak of highly pathogenic H5N1 avian flu in backyard free-ranging flocks in Bhutan has killed 18 poultry and led to 952 more being culled, according to a Jan 11 report to the World Organization for Animal Health (OIE). The birds had died from Dec 19 through Dec 30 in Dagana village in Dagana district, the report said. Trace-back investigations found that 10 more birds had died in the previous month but had not been reported, the report said. A national and a regional reference lab confirmed H5N1 in two samples collected from backyard flocks, whereupon the remaining 952 susceptible poultry were culled to prevent disease spread. The report said the outbreak investigation is ongoing. Bhutan reported eight H5N1 outbreaks in 2012, including its first ever last January.
Jan 11 OIE report
Modeling study finds low pandemic risk from variant H3N2
Novel swine-origin variant H3N2 influenza (H3N2v) does not currently pose a substantial pandemic risk, according to Canadian flu experts, but that could change over time, according to a study in PLoS One. The scientists estimated potential epidemic attack rates (ARs) based on age-specific estimates of serosusceptibility and social interactions. They used a contact network model established for Greater Vancouver to estimate ARs for H3N2v, pandemic 2009 H1N1, and a former seasonal H3N2 strain. The model factored in typical flu characteristics, basic reproduction number, social contacts, and age-specific seroprotection rates (SPRs). The researchers determined an AR of 6% for H3N2v, meaning that 6% of the population exposed would be infected, but the AR grew to 16% in kids 6 to 11 years old. If they modified the SPRs, however, H3N2v ARs of 20% or higher were possible. The authors conclude, "If H3N2v epidemics do occur, overall community ARs are unlikely to exceed typical seasonal influenza experience [which typically involves ARs of 5% to 15%]. However, risk assessment may change with time and depends crucially upon the validation of epidemiological features of influenza."
Jan 11 PLoS One study
