H7N9 is not the only game in town.

Three HCWs who looked after the first H7N9 exported case have developed upper respiratory tract(URTs) infections somewhere during the 15-days between illness onset and lab confirmation. It is well worth noting that H7N9 is not the only virus that can cause URTs.

There are over 200 endemic human "respiratory viruses" that have been associated with URTs including the rhinoviruses (160 of them alone), coronaviruses, adenoviruses, enteroviruses, parainfluenzaviruses, influenza viruses, metapneumovirus, respiratory syncytial virus and bocavirus. Working out what causes a patient's URT is a challenging task, especially when more than one of these viruses can be detected by PCR in a patients airway sample at the same time. 

Differential diagnoses (testing for all the things that may cause the same clinical appearance) is interesting in times of an outbreak. Keep an eye on these HCWs - they could be an important canary in the dark H7N9 mine we've been stumbling about in so far.