Rapid City is at the center of a state and federal investigation into a salmonella outbreak that sickened people in South Dakota and at least three other states.

So far, health officials have confirmed 22 cases of a specific strain of the bacterial-borne intestinal disorder in the four states. All of South Dakota's 11 cases - nine adults and two children - were in the Black Hills area. Six of the 11 victims were hospitalized, five at Rapid City Regional Hospital.

"Everybody's recovering," state epidemiologist Lon Kightlinger of the South Dakota Department of Health in Pierre said Monday. "But since we've had so many of these cases hospitalized, which is fairly unusual, it leads me to believe it is a fairly potent strain."

State health officials sent out a public notice in late December saying that salmonella cases were up slightly for the year and encouraged proper precautions to reduce the chance of infection.

At that time, a Rapid City Regional Hospital official confirmed five people had been hospitalized at the facility that month for Newport salmonella strain. Another patient was treated for salmonella at the emergency room and released, but it was not the Newport strain.

On Monday, hospital spokeswoman Pam Stillman-Rokusek also confirmed that three other cases of the Newport salmonella strain were detected in laboratory samples sent to regional from other medical facilities for analysis.

Additional confirmed cases of the Newport strain since the late-December announcement brought the total in South Dakota and three other states to 22 cases and prompted state health officials to issue another news release Monday.

"On the surface, it looks like 22 different cases, but they have a molecular fingerprint that's almost exactly the same," Kightlinger said. "So we're looking for commonality in them."

Kightlinger declined to name the other states involved, but noted that one is a South Dakota border state and the other two are "far flung." Because of the molecular similarities of the cases in the four states, the states and the Centers for Disease Control and Prevention in Atlanta are investigating for links.

There have been no cases with onsets later than Dec. 17. But Kightlinger suspects there are other cases out there that weren't reported.

"Every time we get a cluster like this, I always consider it the tip of the iceberg," he said. "Because you have so many people who would get a bout of diarrhea and not go to a doctor; they'll just hunker down and tough it out."

With additional news coverage of the salmonella investigation and more contacts with West River doctors, Kightlinger hopes for new reports of cases that could prove valuable in determining the cause of the illness.

There is no indication of new cases of the Newport Salmonella strain since last month. Health officials have not identified a specific food, source or location suspected in the cluster of cases, nor is there a clear connection - beyond the molecular similarities - between the cases in South Dakota and the other states, Kightlinger said.

"None of the cases in the other states traveled to South Dakota during the incubation period. None had food processed in South Dakota, that we know of, or have a grandma in South Dakota that sent them Christmas cookies or goodies," he said.

State health officials confirmed 171 cases of salmonella in South Dakota last year, up from a five-year average of 133.

Most people who suffer from salmonella will recover relatively quickly, but the disease can be more serious and even life-threatening to certain groups, said Dr. Kevin Weiland of Rapid City.

"Symptoms can appear one to four hours after contamination and include diarrhea, vomiting, abdominal cramping and fever," Weiland said. "Healthy people might dismiss it as the flu. But in older people, small children and those with poor immune systems, the infection could be deadly."

Contact Kevin Woster at 394-8413 or kevin.woster@rapidcityjournal.com

Salmonella spread by eating, drinking contaminated items

Salmonella infection is spread by eating or drinking food or water contaminated by contact with infected people or animals.

The following precautions can prevent the spread of Salmonella as well as other food-borne diseases:

* Wash hands with warm, soapy water for at least 20 seconds before and after handling raw poultry or meat. Wash cutting boards, dishes and utensils with hot soapy water.

* Wash hands after playing with pets, especially reptiles such as turtles and iguanas.

* Keep raw poultry, meat and fish away from other foods that won't be cooked, and use separate cutting boards for the raw products.

* Cook poultry and meat to safe internal temperatures and use a food thermometer to check - 165 degrees for poultry and 160 degrees for beef and pork.

* Refrigerate raw poultry and meat within two hours after purchase. Cooked poultry and meat should also be refrigerated within two hours after cooking.

Salmonella symptoms include diarrhea, fever and abdominal cramps, typically 12 to 72 hours after infection. The illness usually lasts four to seven days, and most people recover without treatment. For more information, see the department Web site at http://doh.sd.gov/DiseaseFacts/Salmonellosis.aspx or the CDC Web site at www.cdc.gov/ncidod/diseases/submenus/sub_salmonella.htm.