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Officials have begun cleanup efforts on Mississippi beaches littered with thousands of nutria rats, killed and swept onshore by Hurricane Isaac.

Officials with the Hancock County Emergency Management Agency say that parts of Beach Boulevard from Lakeshore Road to Washington Street in Bay St. Louis have been closed while workers in hazardous materials suits try and pick up the carcasses.

Hancock County EMA officials estimate more than 15,000 swamp rats were killed by Isaac's storm surge and washed up on the beaches. This is a significant increase from the estimated 5,000 earlier reported.

Flies and mosquitoes were beginning to swarm around the dead animals.

Workers are using pitch forks to remove the nutria, which are then loaded onto front end loaders and eventually disposed of in landfills, WLOX reported.

Authorities are concerned about a potential health issue because of the stench from the animals and the possibility that they might bake and explode in the intense heat.

Residents have been advised to avoid the beaches in Hancock County until further notice.

Hancock County faced a similar dead nutria rat problem after Hurricane Gustav impacted the area in 2008.

Hancock County Supervisor David Yarborough says the count after Gustav reached 16,000, but he thinks Isaac's nutria toll will exceed that, as they continue to come ashore with the tide.

"I did an overhead flight earlier today and I spotted some areas that have some heavy debris lines," Yarborough said.

"More than likely there's animals in them as well. It isn't just nutria. We've got hogs, deer, coyotes and plenty of snakes," he added.