Stanford University infectious disease doctor Abraar Karan has seen a lot of patients with runny noses, fevers, and irritated eyes lately. Such symptoms could signal allergies, covid, or a cold. This year, there’s another suspect, bird flu — but there’s no way for most doctors to know. If the government doesn’t prepare to ramp up H5N1 bird flu testing, he and other researchers warn, the United States could be caught off guard again by a pandemic. “We’re making the same mistakes today that we made with covid,” Deborah Birx, who served as former President Donald Trump’s coronavirus response coor…