The cases include 20 deaths , and 102 infection cases . Comment: The new strain was n't known until three weeks ago . Until March , the virus had only been present in birds , which is why they 've become the focus of the investigation . International experts in China to monitor the H7N9 strain .
The cases include 20 deaths , and 102 infection cases . Comment: The new strain was n't known until three weeks ago . International experts in China to monitor the H7N9 strain .