H5N1 bird flu from an extreme case in the US has mutated to attach to human upper airway cells, health chiefs warn. The case, spotted this month in a hospitalised Louisiana man, is the first "severe" bird flu case in the US amid its rapid spread through cows this year. 2 Bird flu could have adapted to infect humans more effectively Credit: Getty In nearby Canada, a healthy teenage boy was admitted to intensive care after contracting the same strain in October.
The new US case, like the one in Canada, is believed to have caught the virus directly from birds in his backyard, not through infected cattle. Tests show both cases involve a mutated version of H5N1 that helps it bind to human upper respiratory cells. This could make it easier to spread between people through coughing or sneezing , raising concerns the virus is adapting to infect people more effectively.
Read more on bird flu FLU BLOW Thousands of turkeys killed after bird flu outbreak days before Christmas VIRAL SPREAD Man has first severe case of bird flu in the US that has pandemic potential Bird flu viruses typically bind to a cell receptor rare in human upper airways, which helps explain why H5N1 rarely infects people or spreads between them. The mutation was not found in the poultry samples collected on the US patient’s home, "suggesting the changes emerged in the patient after infection," the US Centre for Disease Control said in a statement published on Thursday. That was likely true for the Canadian patient .
