An extensive look at wastewater samples taken across the United States from May to July found traces of the H5N1 bird flu popping up -- but only in areas populated by farm animals.

Dozens of viruses have been detected mixing in animals at fur farms in China, some of which are new and have the potential to spill over into humans, researchers said Wednesday.

With cold and flu season approaching, it's worth knowing about another virus out there-albeit extremely rare: bird flu. Like the regular flu, bird flu virus symptoms include fever, cough and a sore throat.

Researchers in Texas detected H5N1 in wastewater from 10 cities, but the risk to humans is currently low. Ongoing surveillance is critical to monitor any potential changes in the virus that could increase its threat to public health.