NEW ORLEANS — All of Mississippi's gulf coast beaches are now closed to swimmers because of those blue-green algal blooms. It's believed the algae is a result of the Bonnet Carre Spillway opening. 

Pascagoula beach was the last to restrict swimming, after algae tests came back positive Sunday. The beaches themselves remain open, but swimming in the water or eating fish caught out off any of the closed beaches could make people sick. 

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Lake Pontchartrain is also facing the algae bloom, with Northshore beaches also closed to swimmers. 

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The algae can cause stomach cramps and vomiting, but how at risk are you?

"I just got back from Mississippi and a lot of people are ignoring the warnings," said Dr. James Diaz, Public Health and Tropic Medicine, LSU Health. 

Eyewitness News sat down with Dr. James Diaz to find out how dangerous this blue-green algae really is.

"If you dunk your head under the water or you swallow it or you get water in your ears or nose, that's when we usually see some problems," Diaz said. 

He warns swallowing it can cause nausea, vomiting, and diarrhea. The algae can also cause rashes and stomach cramps.

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Diaz explained the most common problems, "Skin irritation, dermatitis, and swelling of the lips is a unique feature."

If you have open wounds or cuts, the algae might mean the presence of harmful bacteria.

"If you have one of these and the water temperature is very high, there are pathogens in the water that can cause infections," Diaz said. 

While swimming is restricted, the beaches are still open. Dr. Diaz warns even if you don't touch the algae, it can cause itchy eyes and runny nose.

"Some of the toxins produced by the algae can be aerosolized," he said. 

Young kids and pets are at a higher risk, but as Dr. Diaz tells us these problems aren't too common.

"It's relatively low risk for healthy people," he said. 

Dr. John Lopez with the Lake Pontchartrain Basin Foundation has been watching closely.

"Air on the side of caution," he warns. "It looks to me like maybe conditions are improving in Lake Pontchartrain."

The algae is believed to be a result of the opening of the Bonnet Carre spillway.

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"That reduces salinity of the lake, it also introduces nutrients," Lopez said. 

Because of these hot summer days, it is expected to take weeks once the spillway closes for water to be safe again. 

"All the way through August we could still have algal blooms," Lopez said. 

The Army Corps of Engineers is expected to begin closing the spillway sometime this month.

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