Tamar Raphaeli found a few ticks in her sweat socks after jogging at Mason District Park in Annandale on April 24. Later she felt a bump on her head and her mother removed the burrowing tick discovered there. Five days after that, the 15-year-old was lying in an Arlington Hospital bed with a 105-degree fever and a pink rash that recurred on different parts of her body.

George Spahr went to bed with a headache and blistering fever on the evening of Friday, June 4, after a hard day on his dairy farm in southern Pennsylvania. On the following Sunday, he developed spots around his ankles. His wife thought he had chicken pox. Two days later, while Spahr, 43, was filling a silo, he collapsed.

He and Raphaeli each had the same thing -- Rocky Mountain spotted fever.

Cases of the tick-transmitted illness have been on the upswing this year. Virginia has had 72 reports compared with 42 at the same time last year. In Fairfax County, the health department reports 22 cases so far, more than three times last year's total. Maryland has had 48 cases compared with 30 last year, and there have been 10 in Pennsylvania, one more than last year. The trend is nationwide, with 733 cases reported so far this year, an increase of more than 100 from a year ago, according to the National Centers for Disease Control.

Interestingly, only a relative handful of cases occur each year in the Rockies. The bulk are in the East and South.

Dr. Garth Dettinger, Fairfax County assistant health director, attributes some of the increase in the metropolitan Washington area to the warmer, wetter spring. "That's good for development of ticks," he said. "They start their life cycle earlier, and people get out to the woods earlier in the spring if the weather is warmer. That gets people together with ticks."

The illness, occurring usually between April and October, is transmitted in the East by the American dog tick, and is fatal in less than 5 percent of all cases. According to Dr. Jon Kaplan, an epidemiologist at the centers for disease control, only about one percent of ticks carry the rickettsia causing Rocky Mountain spotted fever.

If a tick releases it into your bloodstream, it takes three to 10 days to get the first symptoms, he said. These include intense headaches, fever, body aches and a rash which often starts at the feet or palms and spreads over the body.

When Tamar Raphaeli's symptoms started five days after her encounter with ticks, she woke up feeling achey, tired and feverish. "I thought maybe I was coming down with the flu," she said.

Dr. Alfonso Vergara -- after hearing the symptoms, taking a temperature of 104, and hearing about the ticks -- told Tamar's mother, Ellen Raphaeli, about "the possibility of Rocky Mountain spotted fever" but "she was not yet ready to believe it."

Mrs. Raphaeli, however, did agree to start giving Tamar a long-acting tetracycline, a drug usually used to combat spotted fever. That evening, Tamar's temperature shot up to 105, and spots appeared on her body. At 2:30 a.m., her parents brought her to Arlington Hospital.

There, doctors continued to use tetracycline and rest to treat Tamar "I was always tired and just slept most of the day," she said. "I ached in most of my muscles and I wanted people to leave me alone. But a whole bunch of different doctors kept coming in. They had never seen Rocky Mountain spotted fever before -- I felt like a specimen. They kept taking my temperature and a whole lot of blood tests."

Her temperature fluctuated and spots kept appearing and then disappearing everywhere on her body except her face. "They told me they would give me intravenous feeding if I didn't eat, so I tried to eat," said Raphaeli, who lost six pounds in the hospital. She was released when her temperature stopped fluctuating and her spots had disappeared, but she still tired easily and stayed home from Thomas Jefferson High School a few more days. "We were probably as aware of Rocky Mountain spotted fever as we were of bubonic plague," said Ellen Raphaeli. "We just hadn't thought of it as particularly relevant to our lives in suburban Virginia." Mrs. Raphaeli didn't really believe the diagnosis until the final tests came back six weeks later with confirmation.

George Spahr's 235-acre farm is full of ticks, he said, and he's always pulling them off his two dogs. But he doesn't remember seeing a tick on himself the week before he got Rocky Mountain spotted fever.

By the time Spahr's wife took him to the Hanover General Hospital emergency room, the rash around his ankles had spread, he was burning with fever and his head felt as if it was ready to split open.

"The doctor knew what I had in five minutes," he said, adding that his fever got so bad "that the sweat under my armpits ran out like water." Because of other complications, he spent 13 days not moving from his hospital bed. Doctors told him to "take it easy" for a while after he got home. Since returning, he's seen ticks on himself and his family. "But now," said Spahr, "if anyone around here gets them, they sure pull them off in a hurry."

Dr. Lawrence Eron, an infectious disease specialist, advises frequent tick checks for anyone, but especially children, who spend time in a wooded, brushy area. A tick must be attached for about six hours to transmit the disease. If one is found, remove it with tweezers or pull it off with tissue-covered fingers. If fever and rash develop, said Eron, "you should consult a doctor and not dismiss it as a viral infection."

Eron's Fairfax County office has seen 15 patients with the disease this year, many of them children. "It's about the greatest number of cases we have ever seen," he said.

Dogs often carry ticks but they seldom catch Rocky Mountain spotted fever, according to Dr. Gregory Parham, a veterinary epidemiologist. Parham advises pet owners that flea and tick collars "are only useful if the dog doesn't have ticks or fleas on him in the first place."

As for reports that some people are wearing pet collars on ankles and wrists to ward off ticks, Parham advises against the practice. He said many contain organophosphates, compounds commonly used as pesticides, which often can cause skin irritations on humans.