HILTON HEAD ISLAND — Residents on Hilton Head Island and in Bluffton are reporting an abundance of marsh rats this year, but it’s not clear whether the rodents’ population has increased as dramatically as some think.

The situation has caused a flood of calls to pest-control companies.

“I’ve had crews in every plantation almost every single day trapping rats and repairing homes to make sure they can’t get in,” said Billy Karijanian, director of operations for Critter Management on Hilton Head. “We are working on 50 to 60 homes a week, trapping rats and critter-proofing the home.”

Karijanian said the population has exploded because of last winter being warmer than usual and plenty of rain this year.

“We didn’t have a freeze last year or this year to kill off some of the population,” he said. “There’s also a lot of food and water to support them. … This has been one of the biggest years for rats that I’ve seen in 19 years.”

John Kaiser with Island Pest Control on Hilton Head, however, contends the marsh rat population – albeit large – has not changed. He and Tony Mills, education director at the LowCountry Institute, say people are just seeing more of them because high tides have driven them from their marsh homes into nearby human homes.

“The tides are covering their habitats and are ending up in people’s yards and homes because there are few places for them to go,” Mills said.

Some residents worry the rats have created a health hazard by carrying infectious diseases such as the hantavirus – a severe, sometimes fatal, respiratory disease that kills about a third of those infected, according to the U.S. Centers for Disease Control and Prevention.

S.C. Department of Health and Environmental Control spokesman Mark Plowden said residents should be cautious but not alarmed.

“I have found no report of hantavirus in S.C. in recent years,” Plowden wrote in an email. “The situation in the area to which you refer is naturally occurring, and has done so repeatedly over the years.”

The agency recommends removal of food, water and items that provide shelter for rodents; covering gaps around fireplaces, walls, pipes, doors, vents, rafters, gables and eaves where rats and mice can get inside.