A strain of a drug-resistant skin disease that has afflicted sports teams, prisons and military units is now a persistent pest among lobstermen and their families on a Maine island.

Over the past two summers, more than 30 people on Vinalhaven have come down with painful and persistent skin infections, which have required repeated treatments with intravenous antibiotics for some of the victims.

There’s no indication that the germ is linked to lobsters, and boiling or steaming them would kill any bacteria that infected fishermen might leave behind, said Dr. Stephen Sears, Maine’s state epidemiologist.

The working theory is that methicillin-resistant staphylococcus aureus, known as MRSA, moves easily among lobstermen because their work — hauling traps, cutting bait, handling lobsters — causes plenty of scraped knuckles, pinched fingers and small cuts and nicks, giving the bacteria a foothold, Sears said.

No deaths have been associated with the outbreak, but lobstermen and others have sought treatment at the island’s medical center. Some have been treated multiple times.

Landon Morton, a lobsterman, has battled staph infections four or five times in the past year and a half, since first coming down with MRSA while working on one of the town’s docks. Just a few weeks ago, he began his latest bout — and his 18-month-old daughter has it, as well.

Morton said there’s no mistaking it for a run-of-the-mill skin rash, because it’s painful.

“It starts with a little red sore,” he said. “Within a couple of hours it swells and turns really red. The first time I had it, about half of my leg was swollen and red. It’s nasty.”

Hospitals have been dealing with infections caused by the “superbug” for 30 years, said Nicole Coffin of the Centers for Disease Control and Prevention in Atlanta. Community-acquired MRSA, the strain that’s making the rounds in Vinalhaven, tends to cause skin lesions, Coffin said. Left untreated they can become deadly.

Perhaps the best-known case of community-acquired MRSA involved the NFL’s St. Louis Rams in 2003, when the CDC was called in to investigate a cluster caused by skin abrasions and locker room contamination.

MRSA is carried on human skin and can be transferred through towels, gloves or other shared items. It’s a bit of a mystery how MRSA arrived on the 1,200-resident island in Penobscot Bay.

Some islanders believe it started with workers on one of the wharves. Some wonder whether the staph is in the water. Others wonder whether it somehow originated with the herring bait that lobstermen use.

All of those scenarios — and the chance of pinning down the culprit — seem unlikely. MRSA is not carried by seafood, so that rules out herring bait and lobsters, Sears said. And while MRSA has been documented in seawater and on beaches, it doesn’t survive in those environments in concentrations that can cause human infection, he said.

To cut down on MRSA infections, people on Vinalhaven are following guidelines recommended by the CDC: frequent hand-washing, use of disinfectants, washing clothes in hot water and setting the clothes dryer on hot.

Morton said he always had good hygiene. These days he takes multiple showers daily, washes his hands frequently and even changes clothes several times a day. He keeps disinfectant wipes close at hand.

“Some people will call it a little bit of a phobia, but it’s to the point where I’m careful about everything I touch,” Morton said. “I’m very paranoid about keeping things clean.”