Tracing SARS virus chain
( 2003-05-16 15:38 ) (1)

With bloodshot eyes and a husky voice, 35-year-old Pu Yonglan said she really missed her 2-year-old son, whom she has not seen for weeks.

"Actually, it was only during my last media interview that I had enough time to miss him," she joked. "I am too busy even to remember when that was."

As the leader of an epidemiological investigation team with the Centre for Disease Control and Prevention of Beijing's Haidian District, Pu has been busy taking care of everything since confirmed or suspected SARS cases were reported by hospitals in the district in mid-March.

Pu and her more than 80 colleagues in the Haidian centre are responsible for interviewing SARS patients to learn about all the people with whom they have had close contact. They are also responsible for disinfection and set up quarantine areas. By the evening of May 13, they had carried out epidemiological investigations into 552 patients.

Haidian District has a population of 1.67 million and contains major specialist infectious-disease hospitals. In the SARS epidemiological chart for the country's capital, it had the most SARS cases, the figures having been gathered from hospitals in the district. By May 14, the number of confirmed cases receiving medical treatment in Haidian hospitals numbered 657 and there were 335 suspected cases.

Over 60 per cent of the patients are not residents of Haidian District. But the battle against the flu-like epidemic in Haidian has always been tougher since most of Beijing's best universities and dozens of big hospitals are located in the district.

China Daily's interviews with different staff members of the Haidian disease-control centre were interrupted by phone calls and other urgent business so many times that it took five hours to do all the interviews.

"Epidemiological investigation are vital throughout the battle against SARS," said 47-year-old Dong Shulan, a member of the SARS specialist section in the disease-control centre.

"We help cut off the possible channels through which the virus could spread and all the first-hand information that we have collected is important for further analysis and research into the spread of SARS," she added.

Dong said she is happy that their work is now bearing fruit as the number of SARS cases is falling gradually, both within the district and in the city as a whole. "This is the best form of repayment for our work," she said.

On the front line

Pu and 14 of her staff handled their first SARS case on March 15.

However, the small crew soon found themselves overloaded with the investigation work as the disease spread quickly. They could rest for only two or three hours a day. "My record was when I worked continuously for 48 hours," said Pu, who has worked with the centre for more than 10 years.

About 70 more doctors from local hospitals and institutions joined the Haidian centre's staff on April 23. "But none of us will get the chance to take a break before the spread of SARS is under control," she said.

"There were a few days when I had just come back to the office after handling one case, another one was already waiting me to go out again," she recalled.

It takes about five or six hours for each team of two people to handle each case if everything goes smoothly, she said.

During those five or six hours, the two investigators first rush to the hospital involved to interview the SARS patient and fill in an epidemiological study chart. Then they go to the patient's home to quarantine the family members and disinfect the whole apartment, the elevators and the corridors of the building. After that, they rush to the patient's workplace for further investigations and disinfection work. Finally, they help the patient's family and colleagues take proper measures to quarantine everyone who has come into close contact with the SARS patient.

The Haidian centre's staff strictly follow the detailed guidelines set by the Ministry of Health for investigations, disinfection work and quarantines, said Pu.

Time limits have been set out. Epidemiologists must get to the hospital within one hour of a case being reported to them. They must arrive at the patient's home within two hours. All work for a particular case must be finished within 24 hours, Pu said.

However, the staff sometimes find it impossible to keep to the time.

For instance, at 8 am on May 8, Haidian Hospital reported that a construction worker had been diagnosed with SARS. The worker, surnamed Zhou, arrived in Beijing for the first time on May 6, having taken the train from Guangzhou, the capital of South China's Guangdong Province. Zhou did not know enough about Beijing to tell the exact location of the construction site where he had worked.

Pu sent four squads to interview Zhou, trying to get more useful information out of him. But all he could recall was three phone numbers that he often called. One of the numbers had expired, the other was always busy and they couldn't get an answer from the third phone number.

Construction sites, schools and hospitals are three key places for observation and protection work by disease-control centres, Pu said. "Quarantines and disinfection are especially important for construction sites, which are relatively messy and where migrant workers often live in small, densely packed quarters."

When they were at their wits' end, Pu asked for help from Zhou Liangluo, the head of Haidian District. The local police then managed to reach the people whose phone numbers Zhou had. They were members of Zhou's family in Southwest China's Yunnan Province. These family members told the Haidian police the specific location of the building site at 2 am on May 9.

By 6 am that same morning, the construction site in the northeast of the district had been disinfected. All 23 workers identified as having come into close contacts with Zhou, from among about 100 workers in total, were quarantined.

No one else has developed SARS symptoms yet, said Pu.

Dong Shulan, a member of the SARS specialist section in Disease Control Centre of Haidian District, said: "The sooner the infected places are disinfected and people who have had close contact (with a SARS patient) are quarantined, that chain of infection will be cut off. "We are trying to protect the whole of society and guarantee a relatively safe and healthy environment."

In so doing, the epidemiological workers have put themselves in a high-risk group as they contact both patients and groups of people in potential danger of infection.

Some people regard the disease-control workers as unwelcome and annoying because they bother patients and their families when they are still in pain, Pu said.

"But none of us has any other choice, right? We have to do the job and do it meticulously for the sake of preventing the further spread of the disease," she said.

Need to be meticulous

Pointing at the two pages of the standard questionnaire, Pu said that is what they have to ask just one single SARS patient. The questions cover all the basic information about the patient, clinical signs, current medical treatment and reactions, the latest history of contact with particular places, people and animals.

Pu admitted that some patients were reluctant to answer the questions but most co-operated when Pu and her colleagues told them about the potential damage that SARS would cause.

The team will meet more difficulties when the weather gets hot, said Pu. She added: "Wearing stuffy protective outfits for hours while doing interviews in the wards can make us faint. Even nowadays, we are usually dripping with sweat when we take them off."

The information gathered by the Haidian disease-control centre staff is sent to the main Beijing centre for further analysis and research, said Dong Shulan.

The workers have been so busy with their routine inquiries and disinfection and quarantine work that they have had little time for rest and have been unable to put their heads together to come up with their own conclusions.

"So far, I haven't been able to figure out exactly how many ways SARS is transmitted except being sprayed at short range," said Dong. "In some SARS cases, we don't even find any history of possible contact with the SARS virus."

"What we still need is more understanding of the importance of our work from all levels of society."