Following an initial assessment for the threat of the Eurasian H5N1 avian flu strain to human health in November, UK health officials today published a more detailed assessment, which found no increasing risk, though the level of confidence is low and the situation requires regular review because of ongoing high transmission in poultry.
The new assessment from the UK's Health Security Agency (HSA) defined six levels of transmission to gauge the threat, putting the United Kingdom at level 3, meaning evidence of virus genetic changes that provide an advantage for adaptation to mammals.
Also, the HSA said it is investigating a small number of flu virus samples that can't be subtyped, but it added there is no evidence they are H5N1 avian influenza. HSA experts document nearly 2,100 human H5N1 exposures during the current reporting year, which began on Oct 1. No infections have been reported. Britain had earlier reported one human H5N1 infection in the previous reporting year involving a person who had close contact with domestic poultry.
Globally, four human H5N1 infections have been reported related to the surge in circulation in poultry and wild birds. One in the United Kingdom, two in Spain, and one in the United States.
More virus in US poultry and wild birds
In US developments, the US Department of Agriculture (USDA) Animal and Plant Health Inspection Service (APHIS) reported one more outbreak in poultry, which occurred in a noncommercial flock of 20 birds in California's Mendocino County.
Also, APHIS reported 221 more H5N1 detections in wild birds, raising the total to 5,221. Many of the latest detections involved snow geese found dead in multiple states. There were also several black vultures found dead in a handful of states.