GALLUP, N.M. (AP) _ A headache and sore elbows were all it took to send one Navajo man 30 miles to the nearest clinic.

Fearful he might have contracted a mystery illness that has claimed 13 lives, Nelson Bitsilly joined hundreds in visiting the Gallup Indian Medical Center in the past week. He said he heard Navajo President Peterson Zah urge his people to seek medical care if they have symptoms of the flu-like illness.

In Pine Hill, an end-of-the-road settlement 50 miles south of Gallup, KTDB disc jockey Martha Pino interrupted the country music twice an hour to deliver in the Navajo language a medical alert issued by the Pine Hill Health Center.

People with fever and muscle aches especially should see a doctor immediately, she said, adding: ''Do not wait.''

The medical alert was first issued a week ago Wednesday, the same day Hank Henio Jr. of Pine Hill died at the nearby Zuni Indian medical center. Henio, who was engaged to Pino's cousin, died a day after feeling achy and tired.

''I'm scared,'' Pino said. ''I'm not afraid to say I'm scared. I'm terrified. We don't know what we're dealing with.''

On Wednesday, the most recent known victim, a 13-year-old girl from east of Gallup, was buried. Dozens of people attended the funeral and burial. Family members demanded privacy, and reporters and photographers were excluded.

Visits are up 30 percent to 50 percent at the Gallup hospital since the outbreak was first reported the last week of May, director Dr. Tim Fleming said.

''We're certainly trying to give them reassurance. There doesn't seem to be a pattern of person-to-person spread,'' Fleming said.

Some tribal members said they have changed their habits because of the killer disease.

''We've tried not to associate with crowds, like going to the malls and stuff,'' said Lyman Martinez, a Navajo from Ganado, Ariz.

''It's scary to go out,'' said his wife, Wylma. The couple are also trying stick with the same foods and drinks they have been consuming, she said.