FAIRBANKS - When Don Ritter started tracking viruses in Alaska more than three decades ago, rabies was ravaging rural parts of the state.
Foxes in the northern and western parts of the state commonly carry the fatal virus. They can pass it to dogs through bite wounds.
Dogs, especially in rural areas, were not always vaccinated against the virus. If they got infected, they could bite people and pass the disease to them.
Rabies requires fast action; the clock starts ticking when a person is bitten by an infected animal. Once the virus takes hold of the nervous system and symptoms start, it's usually too late to save the person.
To prevent this from happening, the patient needs a round of vaccines. Decades ago, that meant 23 shots that could cause side effects bad enough to send people to the hospital.
Ritter helped start a program that boosted the number of animals vaccinated throughout the state and reduced the number of people exposed to rabies. In fact, nobody has died from rabies in Alaska since the 1940s, said Dr. John Middaugh, the state's longtime epidemiologist.
"This is one of these major programs which is a great public health success in Alaska and probably most people don't even know about it," Middaugh said.
Middaugh credits this and other public health successes to Ritter, a man who went to work in the evenings and on weekends to test animals for rabies.
Ritter retired last month, after almost 40 years as the state's virologist.
He didn't set out to work with viruses.
Raised near Chicago, Ritter joined the Army and became a helicopter crew chief. That was his ticket to Alaska in the 1950s. He flew around the state mapping its topography. Years later, he enlisted in the Air Force determined to become a pilot, but he failed an eyesight test.
He returned to college, became fascinated with viruses during a lecture and earned a bachelor's degree in biology. After returning to Alaska, he directed large-scale programs. In the 1980s, one required testing more than 100,000 Alaskans, many of them Natives, for hepatitis B.
The goal was to prevent the spread of the virus, which attacks the liver, by vaccinating those who didn't have protection against it.
"He researched and set up a computer system to keep track of all of that," said Terry Schmidt, a microbiologist who took over the state's only virology laboratory, in Fairbanks, after Ritter retired.
Middaugh remembered several years when Ritter detected new influenza strains in Alaska and helped get them included in the next year's nationwide flu vaccine.
"It's a demonstration of the superb level of expertise in his lab," Middaugh said.
Peg Ritter, a retired teacher who has been married to Don for more than 40 years, said her husband is a perfectionist and thrives on work. She met him during college in California, when he was paying his own way to earn a degree.
"He's worked very hard for what he's done," she said.
A few months ago, his colleagues got together in Anchorage to honor his four decades of work. One by one, they praised his dedication and his ability to convert an aging building into a state-of-the-art lab.
Ritter is humble, a behind-the-scenes type of worker. When his colleagues presented him with a gold pan and a standing ovation, he pushed the thanks back onto them. Many of them talked about Ritter's commitment to the rabies program.
The virus can be detected in an infected animal's brain tissue. To track the virus, health officials shipped heads from potentially ill animals to Fairbanks. They'd arrive in the evenings or on weekends, but Ritter would still run them back to his lab and do the tests himself instead of passing the job to someone else, Schmidt said.
Schmidt said there were very few weeks when Ritter didn't come in at least one day on the weekend to "catch up," as he'd say. If the animal's rabies test came back positive and health officials felt that a person had been exposed to the virus, treatment was started as soon as possible.
"Once a decision to treat is made, then it's full-court press, a public health emergency to get that vaccine and treatment into that person as soon as possible," Middaugh said.
Ritter might still be looking for viruses today had he not taken a trip to Switzerland last year that convinced him there was more to life than his laboratory.
He's planning for more travel now, but he's not sure how else he'll fill his days.
"I don't know," he said. "I think that's going to be the toughest thing."