I believe these agencies may have other kinds of intelligence data such as satellite photos of the (empty?) Wuhan Institute of Virology carpark, spikes in mobile phone activity in the area etc.
So assessments are made on more than just biological principles.
I would argue you are sowing disinfo and I honestly dont know what point you are trying to make.
Spikes and/or significant reductions in activity as indicated by external data sources, and particular the timing thereof, will obviously be very useful for determining the sequence of events.
