H5N1 outbreaks & D1.1 variant
H5N1 bird flu has been confirmed at a state poultry farm in Bengaluru and an outbreak was also reported on a farm in Ivory Coast, while a new H5N1 D1.1 variant is reported as dominant across North America. (deccanherald.com) In Bengaluru authorities culled more than 7,400 birds at the Hesaraghatta facility and put quarantine and containment measures in place, and Ivory Coast notified the World Organisation for Animal Health of its outbreak. (newindianexpress.com) Down to Earth reports the D1.1 variant is spreading along migratory bird routes, killing wildlife and affecting poultry flocks while posing a low risk of human transmission. (downtoearth.org.in)
Bird flu is flaring again in poultry, with confirmed H5N1 outbreaks in Bengaluru and Ivory Coast as a newer D1.1 strain spreads through North American wild birds. (deccanherald.com) (thepoultrysite.com) (nature.com) In Bengaluru, Karnataka officials confirmed H5N1 at the state-run poultry rearing and training centre in Mathkur village near Hesaraghatta and culled more than 7,400 birds after unusual deaths were reported. (newindianexpress.com) (deccanherald.com) Officials told Deccan Herald they imposed quarantine, restricted poultry movement, disinfected the site, and began surveillance in nearby villages, while saying no human infections had been detected so far. (deccanherald.com) Ivory Coast separately notified the World Organisation for Animal Health of an H5N1 outbreak on a poultry farm in Koun-Fao district near the Ghana border, where about 95,000 birds were reported killed by the virus. (thepoultrysite.com) (aol.com) H5N1 is a subtype of influenza A virus that mainly infects birds, and mass culling is a standard control measure because the virus can move quickly through poultry flocks and contaminate farms through droppings, feed, water, or equipment. (who.int) (woah.org) The North American piece of the story is not a new disease but a new genetic mix. Scientists reported this week that genotype D1.1 spread rapidly across U.S. and Canadian migratory flyways in the 2024 fall migration season and displaced earlier H5 lineages in many wild birds. (nature.com) (stjude.org) That study linked D1.1’s rise to wild-bird movement across flyways and said the strain’s expansion coincided with detections in poultry, mammals, dairy cattle, and 17 human cases, though the wild-bird viruses lacked key mammal-adaptation markers seen in some human infections. (nature.com) Public health agencies still describe the risk to the general public as low. The U.S. Centers for Disease Control and Prevention says A(H5) bird flu remains widespread in wild birds and has caused outbreaks in poultry and dairy cows, with human cases mainly tied to animal exposure. (cdc.gov) The wider backdrop is a multi-year global spread. The World Health Organization says the current clade 2.3.4.4b wave has caused unusually large losses in wild birds and poultry since 2020 and reached North America in 2021 before spreading farther across the Americas. (who.int) For now, the immediate response is local and familiar: cull infected flocks, lock down farms, and watch exposed workers and nearby birds for new signs of H5N1. (deccanherald.com) (woah.org)
