6 Sigma Probability Chinese Doctor Died Of Human To Human H7N9 Infection Transmission

Given the known dates of direct and indirect exposure to poultry for Dr Zhang, his disease onset (and self treatment)  falls on the 6 Sigma tail of H7N9's  known incubation period (see chart below). In short, this means that it is extremely unlikely that the Doctor acquired H7N9 from those exposures.

Conversely, the data indicates that Dr Zhang was more likely to have been infected during the time period he was performing surgeries at his Emergency Room. Given that his most recent reported work was performing multiple Emergency appendectomies, a prima facie case can be made he was likely infected during such surgery. 

However, it is important to note that as a Surgeon, he had a much higher risk of exposure to H7N9 from bodily fluids (aerosolized or otherwise) than most people. As such, his exposure does not necessarily indicate increased risk outside of the Hospital environment. But, it does indicate it may be wise to stay away from hospitals during Pandemic flu outbreaks.

Chart Source:
The Lancet