Bird Flu Jumps from Cows to Chickens to Humans in Colorado

Five workers infected as high temperatures complicate protective measures during poultry culling

Four cases confirmed by CDC, with one presumptive positive awaiting confirmation.
Symptoms among infected workers range from conjunctivitis to flu-like respiratory issues.
Virus spread linked to movement of cows, people, and equipment between farms.
No evidence of human-to-human transmission; investigations into the infection route continue.
Global preparedness efforts include vaccine development and enhanced surveillance.