The UK Health Security Agency (HSA) today reported two more asymptomatic H5N1 avian flu detections in people who had contact with sick poultry, raising the country's total to four from its ongoing surveillance program.
In other developments, animal health officials in Finland today reported four more H5N1 detections on fur farms, which follows an announcement yesterday of an outbreak in blue foxes at a fur farm.
Positive tests on people at 2 farms
In a statement, the HSA said contact tracing hasn't turned up any related human avian flu infections.
Meera Chand, MBBS, the HSA's director of clinical and emerging infections, said current evidence still suggests the virus isn't spreading easily from birds to people.
"These detections can follow contamination of the nose and throat from breathing in material from the environment, or can be due to infection," she said. "It can be difficult to distinguish these in people who have no symptoms. Following any detection, we will immediately initiate the appropriate public health response."
Health officials said outbreaks in poultry farms have continued at a low level over the summer, but transmission of the virus in wild birds remains high across the United Kingdom, especially among gulls and terns. The two latest people who tested positive were exposed at different farms.
Scientists obtained a partial viral sequence from one person and a full sequence from the other. Both viruses belong to the 2.3.4.4b H5N1 clade and belong to the UK AIV48 genotype.
Earlier this week, global health groups warned of an ongoing threat from H5N1 to people, based on continuing outbreaks in birds and increasing detections in non-human mammals. Though human cases, now at 10, remain sporadic, some were severe or fatal, while others are thought to be the result of environmental contamination of the respiratory tract. All involved people who had contact with sick birds.
Scientists continue to closely watch for any changes in the virus that give it the ability to more easily infect humans. Researchers have already documented changes in the PB2 gene that are linked to increased replication in mammalian cells. And though some of the changes give the virus the ability to bind to human-like receptors, there's no sign of a preference change from avian to human airway receptors.
H5N1 confirmed at 4 more Finnish fur farms
In related developments, the Finnish Food Authority (FFA) today said tests have confirmed H5N1 at four more farms, raising the total to five.
Officials said the virus is the same one found at the facility reported yesterday. Of the new detections, two are in Kauhava, one is in Kausti, and one is in Halsua. The farms are located in the west central part of the country.
At one of the new outbreak farms, the virus was found in both blue foxes and minks. Last October, Spain reported an H5N1 outbreak in minks. Health officials are closely tracking increasing detections in mammals to assess virus changes and because minks have been suggested as a possible mixing vessel for respiratory viruses.
Source : umn.edu