HARRISON COUNTY - Officials in Mississippi have closed off beaches in two counties over an algal bloom that poses a health risk to swimmers.

The News Star reports the Mississippi Department of Environmental Quality announced the latest closures Thursday, bringing the total number of beaches closed in Hancock and Harrison counties to 12 because of the growing blue-green harmful algal bloom.

It's suspected the spread of the algae is due in part to the extended opening of the Bonnet Carre Spillway.

Health officials warned of the same algae spreading throughout Lake Pontchartrain last week. The algae can be harmful to people who come into contact with it, causing rashes, stomach cramps, nausea, diarrhea and vomiting. High exposures of toxins associated with the algae can potentially affect the liver and nervous system.

The algae can also make its way into fishes' organs so fishing in these areas is also not recommended.