The nation's worst outbreak of sickness from raw oysters appears to be easing nearly two weeks after the industry voluntarily stopped harvesting in Galveston Bay.

Since early June, there have been 316 cases of flulike diarrheal illness in people who ate raw oysters from the bay. After seeing 50 new cases each day at the height of the problem, state health officials said only 16 cases were reported over the weekend.The ill were in Texas, Florida, Oklahoma and Tennessee.

Three or four people have been hospitalized because of the illness, Texas health department spokesman Larry McBride said Tuesday.

Health officials suspect that extreme drought and heat have caused bacterial microorganisms to rapidly reproduce. Others believe that a new, more resilient strain of bacteria has emerged.

Bacteria are always present in the oysters but usually not in quantities high enough to make people sick.