St Publius by ydislins
Here's what the KJV has to say:
"In the same quarters were possessions of the chief man of the island, whose name was Publius; who received us, and lodged us three days courteously. And it came to pass, that the father of Publius lay sick of a fever and of a bloody flux: to whom Paul entered in, and prayed, and laid his hands on him, and healed him. So when this was done, others also, which had diseases in the island, came, and were healed: Who also honoured us with many honours; and when we departed, they laded [us] with such things as were necessary."
There were no Christians on the island at that time, which almost all commentators take to be Malta. Even today those islanders are known for their hospitality.
As to the "bishop" business, there was a tendency of early writers to assign offices to almost anyone mentioned in the NT. A look through the Catholic Encyclopedia of about 100 years ago (at http://www.newadvent.org/cathen/index.html ) will show you this. (BTW that site doesn't have an entry for Publius.) When Luke calls him the "the chief man of the island" he means a chief or secular leader or local king of some kind.
His father's disease was probably dysentery, which often proved fatal in those pre-antibiotic days, so Paul's cure was no trivial thing.
Finally, here's what one of our Jehovah's Witness publications has to say:
"(Pub′li·us) [from Lat., meaning “Popular”].
A wealthy land-owning resident of Malta who kindly entertained Paul and those with him for three days after their shipwreck on the island. Paul, in turn, healed Publius’ father of fever and dysentery.—Ac 28:7, 8.
Publius was “the principal man of the island.” In this instance such a designation appears to denote an official title comparable to governor, probably denoting the leading Roman officer on the island." -From Insight on the Scriptures, vol. 2, p. 714