Another duty of the Marine Hospital OD that I recall from my 2 yr hitch there as a Gnl. M.O. was “Quaratine Calls.” US Seaports of Entry (where you can clear in) all, theoretically at least, had a designated “Quarantine Officer”. In most that fell to the USPHS, though I believe ports w/o a PHS presence might use a civil MD (local county health officer, etc,) under contract.
Once upon a time, when things like cholera, typhus and tb could be, and were imported, ports had actual isolation “quarantine stations.” Galveston had one but it was long closed by the ‘60s. But masters still had rules and conventions to follow, as you MM officers know better than I do. When “requesting pratique” as they used to say, they had certain things that had to be reported.
If infectious disease was suspected onboard, that got reported, via the CG, to the Marine Hospital. The duty of responding fell to the OD (a 24 hr rotation). Depending on the nature & circumstances of the report, it most often was handled by the OD boarding first at the dock. But a few times, I recalll getting treated to a helo or small boat ride out to an anchored or offshore vessel. Never found much beyond flu, chicken pox, mumps, etc. , but I did get the treat of having to negotiate one of those damn swinging rope ladders with the wooden steps a few times! In my PHS whites too! Weren’t all white when I got back! ;-)).
I’m sure that whole thing gets ignored 99.9% with arrivals now, but I wonder who would handle it if they did have something really serious and contagious aboard a ship nowadays?