U.S. Army medical officials in Germany said Saturday they expect to get lab results back Monday indicating whether four more servicemembers at Landstuhl Regional Medical Center are sick with H1N1 influenza, or swine flu.

Tests on two other military members at the hospital came back positive for the virus Thursday, hospital officials announced Friday, making them the first confirmed cases of the new human strain of H1N1 among U.S. military personnel in Europe.

In the meantime, health officials are trying to determine the source of the infection among the small group at Landstuhl, while working with their base communities and units to remain vigilant against any further signs of the virus.

The confirmed cases at Landstuhl are two U.S. soldiers, from Mannheim and Stuttgart, Germany, said Col. Evelyn Barraza, Europe Regional Medical Command preventive medicine consultant and department of preventive medicine chief at Landstuhl.

The four “probable” cases involve two sailors from Naples, Italy, an airman from Spangdahlem Air Base, Germany, and another airman from Incirlik, Turkey.

All shared in “similar activities” at Landstuhl but were not being treated for combat-related injuries, Barraza said Saturday, declining to provide more detail due to patient confidentiality.

Health officials were first tipped off to the swine flu cases when one of the infected soldiers went to the emergency room at Landstuhl on Sunday, where an “astute” provider took a nasal-throat swab for H1N1, Barraza said.

One of the probable cases — a sailor from Naples — was identified only after health officials began interviewing servicemembers with whom the soldier had been in contact. The sailor had been at Landstuhl for only two days before getting sick, but his symptoms were mild enough that he didn’t seek medical attention, Barraza said. Because the sailor had the earliest onset of symptoms, it’s possible he may have contracted the virus in Naples, Barraza said.

That’s “just an assumption … based on the sequence of events,” Barraza said. “We have no confirmation of that.”

But officials in Naples said they’ve concluded Naples was not the source of the flu cases in Germany.

“After conducting and reviewing all of the medical interviews, evaluations, and lab tests completed in Naples in the last 48 hours and the history of the probable H1N1 cases in Germany, at this point, I do not find any evidence the source of the H1N1 virus is here in Naples,” Dr. (Cmdr.) Timothy Halenkamp, occupational and environmental medicine specialist in Naples, said in a statement e-mailed to Stars and Stripes on Saturday. “Therefore, no additional public health preventive measures are recommended at this time.”

Another active-duty member stationed in Sigonella, Sicily, who tested positive for Type A influenza virus late last month tested negative for swine flu, Sigonella hospital spokeswoman Petty Officer 1st Class Clarissa Rosalin said Saturday.

According to the World Health Organization, as of Friday, 69 countries have officially reported a total of 21,940 cases of influenza A, H1N1 infection, including 125 deaths. The disease has also spread to all 50 U.S. states, the Centers for Disease Control and Prevention says.

The six servicemembers at Landstuhl with confirmed and suspected H1N1 are in medical isolation, housed in a building separate from the hospital, Barraza said. Someone brings them their meals and medication and monitors their progress, she said. Their days are spent watching TV and reading. This weekend they may get to go outside, but they will be limited to the vicinity around their quarters, she said.

All are on the antiviral flu medication Tamiflu and responding well to it, Barraza said. She described their symptoms as “so far, mostly mild,” with fever, chills and head and back aches. Two servicemembers, however, experienced nausea and vomiting. But none of the individuals were hospitalized for the illness.

While health officials haven’t ruled out the possibility that the infection has not been contained, at this time there are no more suspected H1N1 cases at Landstuhl or in the base communities from which the servicemembers came. Individuals who came into contact with the servicemembers at Landstuhl have been interviewed and some have decided to take anti-flu medication.

While this is outside the typical flu season, “this is not your typical flu,” Barraza said of H1N1.

“Most people have not been exposed to this before, so we’re going to see more individuals getting the flu who would not typically get it this time of year,” she said.

A respiratory illness, swine flu is transmitted through coughing and sneezing.

Coming down with flu-like symptoms, however, need not be cause for panic and an immediate visit to the doctor’s office, Barraza said, especially if you’re managing OK with self-care at home. But if symptoms worsen or if someone has underlying medical conditions such as diabetes or a respiratory problem, he or she should seek medical treatment, she said.

Health officials also advise people in Europe’s military communities to continue to follow preventive guidelines recommended by the CDCP.

Stars and Stripes reporter Sandra Jontz contributed to this story.

How to stay healthy

Here are some guidelines to prevent contracting the flu:

Stay informed. The CDC Web site will be updated regularly as information becomes available.

Influenza is thought to spread mainly person-to-person through coughing or sneezing of infected people.

Take everyday actions to stay healthy.

Cover your nose and mouth with a tissue when you cough or sneeze. Throw the tissue in the trash after you use it.

Wash your hands often with soap and water, especially after you cough or sneeze. Alcohol-based hand cleaners are also effective.

Avoid touching your eyes, nose or mouth. Germs spread that way.

Stay home if you get sick to limit contact or spreading infection to others.

Follow public health advice regarding school closures, avoiding crowds and taking other social distancing measures.

Find healthy ways to deal with stress and anxiety.

Source: Occupational and Environmental Medicine department; U.S. Navy Hospital, Naples, Italy