“Of course, it helped” early on, said Ravshan Maimulov, director of a regional antiplague service in Kyrgyzstan who examined the teenage plague victim when he died in 2013. He used the same quarantine plan that he had instituted after the boy’s death to respond to the coronavirus in March.

When the 15-year-old had arrived at the village hospital, “the body was still damp from sweat and I felt swelling under the armpits and chin,” Mr. Maimulov said. But the boy was too far gone to save, and he died within hours.

Mr. Maimulov, 57, trained at a Russian antiplague institute called Microbe. After the boy’s death, he had the authority to immediately put in motion plans for a lockdown, even though at that point they had only a partial diagnosis.

He relayed the news to a regional governor in code — they would need to implement “Formula 100” — lest word leak and inhabitants of the village, Ichke-Zhergez, should try to flee before the door slammed shut.

“We needed to prevent them all from running away,” he said. By the next morning, police checkpoints were in place and the village was sealed.

On his recommendation, the authorities in the surrounding Issyk-Kul region used the same approach in March in introducing coronavirus lockdowns. “We worked under the operative plan for the plague,” Mr. Maimulov said in a telephone interview. The region of about half a million people has reported three coronavirus cases, he said. Kyrgyzstan has reported five deaths.