The group, most often referred to as RAM, has sent health expeditions to countries like Guyana, India, Tanzania and Haiti, but increasingly its work is in the United States, where 47 million people — more than 15 percent of the population — live without health insurance. Residents of remote rural areas are less likely than their urban and suburban counterparts to have health insurance and more likely to be in fair or poor health. According to the Department of Health and Human Services, nearly half of all adults in rural America are living with at least one chronic condition. Other research has found that in these areas, where hospitals and primary-care providers are in short supply, rates of arthritis, hypertension, heart ailments, diabetes and major depression are higher than in urban areas.

And so each summer, shortly after the Virginia-Kentucky District Fair and Horse Show wraps up at the fairgrounds, members of Virginia Lions Clubs start bleaching the premises, readying them for RAM’s volunteers, who, working in animal stalls and beneath makeshift tents, provide everything from teeth cleaning and free eyeglasses to radiology and minor surgery. The problem, says RAM’s founder, Stan Brock, is always in the numbers, with the patients’ needs far outstripping what his team can supply. In Wise County, when the sun rose and the fairground gates opened at 5:30 on Friday morning, more than 800 people already were waiting in line. Over the next three days, some 2,500 patients would receive care, but at least several hundred, Brock estimates, would be turned away. He adds: “There comes a point where the doctors say: ‘Hey, I gotta go. It’s Sunday evening, and I have to go to work tomorrow.’ ”