By HENRY SANDERSON (AP) – 3 days ago

BEIJING — Authorities killed rats and fleas on Tuesday as they disinfected a town sealed off after three people died of pneumonic plague in a remote farming town in northwestern China, according to the provincial health department.

Police set up checkpoints around Ziketan in Qinghai province after the outbreak was first detected last Thursday. The lung infection is highly contagious can kill a person in as few as 24 hours if left untreated.

Medical staff are disinfecting the area and killing rodents and insects that can be carriers for the bacteria, a notice on the provincial health department Web site said. Authorities are keeping close track of people who came into contact with those infected.

Authorities urged anyone who had visited the town — more than 300 miles (480 kilometers) west of Beijing — since mid-July and has developed a cough or fever to seek hospital treatment. Pneumonic plague is spread through the air and can be passed from person to person through coughing.

The latest victim was a 64-year-old man named Danzhi, the official Xinhua News Agency said.

He was a neighbor of a 32-year-old herdsman in Ziketan and a 37-year-old man who died earlier. A further nine people — mainly relatives of the herdsman — are infected and in a hospital, according to the local health bureau.

Of those, one is in an extremely serious condition and one other has developed symptoms of coughing and chest pain, but the rest are in stable condition and there have been no reports of new infections, Xinhua and the health department said.

Police checkpoints were set up in a 17-mile (28-kilometer) radius around Ziketan and people were not allowed to leave, a resident said. Many shops remained closed Tuesday, residents said, although more vehicles were out on the street.

Some people tried to leave the quarantined area on Monday evening after the third death was reported, mostly by foot, one resident reached by The Associated Press said Tuesday.

"A lot of people ran off last night when they heard that another person died of this plague. They are mostly from other provinces," said a foodseller surnamed Han who runs a stall at the Crystal Alley Market. "They headed back home with food, mineral water and their donkeys."

It was unclear if the people who headed out of the town made it past the police checkpoints. Officials at the local and provincial level were unavailable to comment.

According to the World Health Organization, pneumonic plague is one of the deadliest infectious diseases, capable of killing a person 24 hours after he or she gets the disease.

A 2006 WHO report from an international meeting on plague cited a Chinese government disease expert as saying that most cases of the plague in China's northwest occur when hunters are contaminated while skinning infected animals.

Pneumonic plague is caused by the same bacteria that causes bubonic plague — the Black Death that killed an estimated 25 million people in Europe in the Middle Ages. However, bubonic plague is usually transmitted by flea bites and can be easily treated with antibiotics.

Copyright © 2009 The Associated Press. All rights reserved.