Phil, in my experience, rotting flesh, burnt flesh and passed gas very quickly circulate to the cockpit. If the suspected disease is sufficient for the caregivers to protect themselves from airborne spread, then I think the pilot should as well. The full face mask is a little much in some circumstances, but it's better to have more protection than insufficient protection, and the one I'm referring to integrates extremely well with helmets, comms, and flying duties. We got into this when SARS was a concern. big concern for one hospital when a SAR helicopter showed up during the SARS outbreak. Definite over-reaction.