When Warren E. Johnson got a call to help support the war effort, the Air Force gave the Loudoun County physician just a few hours to make arrangements for thousands of patients.

It wasn't something he enjoyed. "It's not something we looked forward to for anybody's sake," said Johnson, who practices family medicine in Purcellville.

After 20 years as one of the few doctors in western Loudoun, Johnson had grown fond of the toddlers, families and expectant mothers he cared for, and he didn't want to leave them in the lurch, said his wife, Carol.

"We got a call at 6 o'clock Thursday, and he had to report by midnight Friday. We had 30 hours to put our life in order," she said. "It upset him greatly to tell his patients."

But as an Air Force reservist, he had no choice. Johnson, 54, was ordered on Jan. 25 to help replace regular military physicians at the Andrews Air Force Base Malcolm Grow Medical Center in Prince George's County. His unit, the 459th USAF Clinic, was called in because the regular doctors were starting a military hospital in England to support the war.

News of his notification spread quickly through western Loudoun, in part because the loss of a single doctor means losing a third of the doctors available. Johnson has practiced medicine in his Purcellville office, and in the area's rural homes, for 20 years.

"Everybody was pretty much disappointed," said Johnson, who lives on a farm north of Purcellville with his wife and several of their five children. "This is the first time we've been called back to active duty."

Robin Juncal, 28, of Purcellville, already misses Johnson. When he was called up, she was beginning the last month of her pregnancy. Juncal said she now has to get to know another doctor before her baby is born, and she has to find another pediatrician for her 2-year-old daughter.

"You kind of build up a rapport and all of the sudden he is activated," she said. "He is what you think of when you think of a family doctor. He'll talk to you as long as you sit there."

Carol Johnson said people stop her everywhere she goes to ask her about her husband. They have called to wish the family luck. One woman left flowers for them, she said.

"It has been very traumatic for them," she said of her husband's patients. "They just call up in tears or stop you in the supermarket."

Warren Johnson said he is doing much of the same sort of work as he did at the Loudoun Medical Center, where he served recently as chairman of the Family Medicine Department. Mostly he delivers babies, something he still does at home for patients in Loudoun, Johnson said.

Johnson said he referred his patients to colleagues James Towe, of Purcellville, and Peter Chopivsky, of the Loudoun Family Practice in Leesburg. He sent about 30 notes to his pregnant patients, advising them of the need to find another doctor.

Records of his patients will be made available to other doctors, Johnson said, and he may try to continue to have Thursday evening hours in Purcellville.

Although his orders say Johnson has been called up for one year, the orders can be extended for another year if the war continues that long, he said. And though he is now stationed at Andrews Air Force Base, he could be transferred anywhere, including Saudi Arabia, if the Air Force deems it necessary.

"It's a possibility," he said. "They'll put you where they need you."