We've seen version of the classic plague doctor's mask, shaped like a bird's beak and filled with aromatics to prevent inhaling the deadly miasma. While those did exist during the 17th century, they weren't universal. They were kind of expensive, so doctors and others who were charged with treating plague victims were more likely to wear something akin to what you see above, which resembles a cross between modern medical hazmat suits and Ku Klux Klan robes.
The sleeves on this get-up are tight to the wrist like modern protective gear, which fits the admonition above to not wear fancy sleeves (Ruisinger questions the 1656 engraving on this basis; the man has voluminous sleeves and may not even be wearing gloves. To this I would suggest that views on miasma were a matter of opinion, not science). The most interesting aspect for me is that the hood has a long bib at the front; a feature shared with two of the Italian beaked masks that I featured in my other article. Perhaps those were the ‘Gucci’ option, or just an alternative view on what would work best?
Read more about the features and variety of the PPE of centuries past at the BS Historian. -via Strange Company