Larry Webster has been working at Mount Wilson Observatory outside Los Angeles for more than 30 years, doing everything from keeping toilets flushing and adjusting mirrors to mapping sunspots. In September 2006, the 51-year-old solar observer came into work looking more like he was 90. He was dehydrated, jaundiced and had lost a lot of weight. Although he spent a month in and out of emergency rooms for symptoms of nausea and vomiting, doctors were uncertain what had caused his illness.

So Webster began his own investigations into the source of the ailment and his mysterious case would eventually pique the interest of California health officials and convince an entomologist named Tom Schwan to fly halfway across the country in order to catch ticks inside the historic observatory.

It all started in the fall of 2006 when Webster invited a few local astronomers out to the 24-inch (61-centimeter) Snow solar telescope to test out a few filters he was considering purchasing to look at the sun's chromosphere. Beforehand, he thought he should sweep away rodent feces that had accumulated and throw out some old cardboard boxes, because the telescope had only been used intermittently since astronomer George Ellery Hale first installed it in 1904. "Observatories are almost always in remote sites," Webster explains, "This particular building—being so old—was more accessible by mice and chipmunks."

About four days after the cleanup, his wife Elisa noticed two red circles on each of his shins just above the sock line, but he didn't think anything of it. The bites faded over the next week, but just after dinner on Saturday, September 17, Webster experienced a sudden fever, shaking chills, and joint and muscle pain. "I was laying down so sick that I didn't feel like I could get up," he says, "That progressed to nausea and vomiting."

Webster went to see his doctor the next Wednesday, who told him he'd contracted a nasty stomach flu and gave him some medication to reduce his vomiting. But he threw up again the next day and felt so bad he went into the emergency room. Doctors there put him on an IV to rehydrate him, gave him pain relievers, and analyzed his blood and urine, releasing him later that night with another flu diagnosis.  Webster's illness would return two more times before he was finally hospitalized and given his first dose of antibiotics. The doctors said he was recovering from a case of mononucleosis. "I was let go from the hospital and I felt better," he says, "but the whole thing bothered me, and being a scientist by nature I tried to understand what I had."

He went to the U.S. Centers for Disease Control Web site, along with several others, reading about any disease that could be carried by a rodent. He read about rabbit fever and hantavirus, and finally came to a category called relapsing tick fever, caused by a spirochete bacteria present in wild rodents and transmitted by soft-bodied ticks. So, he called his doctor. "Oh, no," she told him, "that's a Third World disease. We don’t have that in this country."

Webster was unconvinced. Soft-bodied ticks are found in dark recesses like caves, which he says was a lot like the 150-foot- (45-meter-) long corrugated steel building that housed the old telescope.  He decided to build himself a tick trap, and read that the pests are attracted by carbon dioxide. "I took a piece of dry ice [frozen CO2]," he says, "and wrapped it in pieces of terry cloth and then duct taped them to these long bamboo sticks I got at a garden supply store." The next day, he pulled the sticks from some recesses and discovered what looked to his untrained eye like a soft-bodied tick. He sent the period-size insect to the University of California, Riverside, where a professional entomologist confirmed his diagnosis.

By now, Webster was a man obsessed. First, he convinced a new doctor to prescribe him tetracycline, the preferred treatment. Then, since he couldn't find much information on ticks transmitting relapsing fever in southern California, he tracked down Tom Schwan, the world's relapsing tick fever expert who works at the Rocky Mountain Laboratory of the National Institute of Allergy and Infectious Diseases. Schwan agreed to run a DNA test on the ticks and confirmed that they contained the spirochete Borrelia hermsii. "With the vector and spirochete found in the very room where Larry was exposed," Schwan says, "I was convinced he had contracted relapsing fever."

If it was true, Schwan realized, it would be the first new case of relapsing tick fever in Los Angeles County since the 1930s. Although the disease was known from other parts of California, he felt that the discovery warranted a collecting trip to the telescope to establish a causal relationship between the microbe and the disease and to raise awareness of the illness. In 2007, he and Webster caught live ticks and allowed them to feed on mice in the lab. Within a week, most of the animals had ruffed hair and tested positive for the disease. Then, in July and October 2008, the team set out rodent traps and found that wild animals in the region tested positive for antibodies to the disease.

Today, Webster has made a full recovery and now works as the site manager for Georgia State University's Chara Array.  As it happens, Schwan is also something of a closet astronomer with an affinity for "optical scientific instruments." He's had a Unitron telescope since he was a kid, and after meeting Webster, he bought a new Spencer Browning & Co. telescope on eBay to go with his antique microscope collection. Just the other night, he had been gazing at the stars in Montana trying to find Neptune above Jupiter.

Schwan and his team describe their work in the July issue of Emerging Infectious Diseases. Notably, Webster is listed as a co-author, placing him in the pantheon of scientists who have studied their own infections. "This disease is underdiagnosed and underreported," Schwan says. "Larry was the guy [who] put this infection on the map."