The Hawai'i Department of Health has confirmed 10 cases of salmonella infection on O'ahu since February and officials believe these people became ill after eating poke made from previously frozen imported 'ahi.

No one was seriously ill, although two suffered dehydration and were briefly hospitalized , said Janice Okubo, DOH spokeswoman. The first case was reported on Feb. 27 and the latest on April 6, she said.

The Health Department interviewed the patients and the common link was each reported eating some form of prepared raw fish, usually in the form of poke, Okubo said. The fish was previously frozen 'ahi, most likely from Asia, she said.

The DOH did not say where the tainted poke was purchased.

"We go through a chronology of what they did, what they ate, what they could have been exposed to and when we find something that's common among the individuals , then we do further investigation into sources, where distribution patterns may have occurred," Okubo said. "It is a very complicated process. We don't want to implicate an organization or a business that didn't have any fault."

As of April 12, there have been 13 confirmed cases of this salmonella Paratyphi B infection in five other states and the DOH is working with the U.S. Centers for Disease Control and Prevention to determine if those infected also were exposed to raw 'ahi.

Okubo said if the source or sources of the contamination can be found, measures can be taken to prevent it from happening again.

"The best thing that could happen is we can find the source and prevent it from occurring or prevent the source from supplying fish or teach them to take the precautions so they don't distribute fish that is contaminated ," she said.

Guy Tamashiro of Tamashiro Market said frozen 'ahi "comes from all over" the world, but the primary sources for stores in Hawai'i are the Philippines, Indonesia and Vietnam. He said he wasn't aware of the salmonella problem and said his store sells mostly fresh local fish.

DOH QUESTIONED

At market prices, previously frozen 'ahi sells for $6.99 to $7.99 a pound, compared with $8.99 to $15.99 for fresh tuna, he said. Tamashiro said a good cut of fresh fish has a better texture, taste and color than the frozen fish, but fresh doesn't necessarily mean better.

"There's nothing wrong with good frozen. I always say, a good frozen is better than a junk fresh," Tama-shiro said.

He added that he wondered if the DOH is correct in its conclusion that the cause of the illness was the raw fish.

"Is it just the poke, or two other items or three other items?" Tamashiro said. "They probably asked all those people did you eat this, this, this or this and raw fish was probably one of the first things on their list. But in Hawai'i, everybody eats poke. Very few don't."

Dr. Chiyome Fukino, DOH director, said she is concerned about the latest outbreak because it is similar to a cluster of cases investigated two years ago. Between 2007 and February 2008, she said there were 35 confirmed cases on O'ahu.

An investigation identified raw imported 'ahi used in poke as the source of the illness, but the department was unable to trace the bad fish to a single source.

MANY 'RIDE IT OUT'

Salmonella typically causes diarrhea and is accompanied by abdominal cramps and fever, the DOH said. Symptoms begin within one to four days after exposure to the bacteria.

Okubo said there may have been more than the 10 confirmed cases because many people do not go to the doctor when suffering these symptoms. She said this particular strain is confirmed in five to 10 cases out of the 300 cases of salmonella reported each year.

"Many don't go to the doctor, they just ride it out," Okubo said. "Some people have very mild symptoms or just an upset stomach, so there are probably a lot of salmonella cases that don't get reported."

The DOH is telling people to be careful when feeding raw products to elderly adults or young children. Others who should be take precautions are people who have underlying health conditions.

"We want to remind people that anytime you eat a raw animal product you incur some amount of risk," Okubo said. "You just want to decide based on your own health and your own situation whether that's something you feel comfortable with."