Cats that became infected with bird flu might have spread the virus to humans in the same household and vice versa, according to data that briefly appeared online in a report from the Centers for Disease Control and Prevention but then abruptly vanished. The data appear to have been mistakenly posted but includes crucial information about the risks of bird flu to people and pets.
In one household, an infected cat might have spread the virus to another cat and to a human adolescent, according to a copy of the data table obtained by The New York Times. The cat died four days after symptoms began. In a second household, an infected dairy farmworker appears to have been the first to show symptoms, and a cat then became ill two days later and died on the third day.
A 13-year-old girl in British Columbia developed a severe and life-threatening case of H5N1 (bird flu) in November 2024. Initially presenting with mild symptoms like conjunctivitis and fever, her condition rapidly worsened within days, leading to severe respiratory distress, kidney failure, and dangerously low blood cell counts. She was transferred to a pediatric ICU, where tests confirmed she was infected with a highly pathogenic avian influenza strain.
Her illness was so severe that she required two weeks of extracorporeal membrane oxygenation (ECMO)—a life-support machine that takes over heart and lung function—indicating extreme lung failure. She also underwent multiple blood transfusions and plasma exchange therapy to combat cytokine-related complications and stabilize her dangerously unstable condition. Despite receiving three different antiviral drugs, the infection was so aggressive that she remained critically ill for weeks.
Genetic testing of the virus revealed mutations that may enhance its ability to infect human respiratory cells, raising major concerns about its potential for adaptation to humans.
