Return of SARS Sparks Concerns About Lab Safety
A SARS outbreak that apparently began in a Chinese laboratory represents a dangerous turn of events: the medical-science community, which last year played the lead role in vanquishing the disease, is now becoming the chief risk for its potential resurgence.
China yesterday reported four new suspected cases of severe acute respiratory syndrome, on top of two confirmed and two suspected cases announced Friday. The four new cases are all in people who came in close contact with one of the confirmed patients, a 20-year-old nurse in Beijing, surnamed Li.
No new SARS infections were reported in Anhui province, where two of the cases announced Friday were located. Nonetheless, the Beijing cases are heightening fears of other infections just days before millions of travelers are expected to jam trains, buses and planes for the May Day holiday, complicating efforts to contain any potential spread of the disease.
"These four cases mean that we're now into a third generation of transmission," said Dick Thompson, a spokesman for the World Health Organization in Geneva. "It's gone from a 26-year-old lab worker to her nurse, and from the nurse to her family members" and a person staying in the same hospital room, he said. More than 300 people who had contact with the cases in Beijing and Anhui have been quarantined so far.
If the ultimate cause of the cases is confirmed to be a laboratory mishap in Beijing, as Chinese officials believe, it would mark the third and the most-serious such incident since an international SARS epidemic faded away in mid-2003. Lab errors in Singapore and Taiwan last year resulted in two people becoming infected. Those cases were contained and the patients recovered, but the recent Chinese infections are believed to have led to at least six secondary transmissions of the virus, including to one person who has died.
At the request of the Chinese government, the World Health Organization is launching an investigation into the incident that Mr. Thompson described as "intensive." The first members of a WHO team are scheduled to arrive in Beijing today. In addition to biosafety experts, epidemiologists are arriving to help Chinese health authorities track down people who may have come in contact with the patients. "The threat to public health is still small and limited," Mr. Thompson said. But he said the organization can't be sure that the disease has been contained until 20 days have passed without any new cases -- twice the maximum incubation period of the virus.
The cases put an uncomfortable spotlight on safety standards and practices at laboratories that handle the virus. After the disease killed 774 people and infected more than 8,000 world-wide, the chain of person-to-person transmissions of SARS was broken last year thanks largely to the effort of scientists, health-care workers and public-health officials. China has also taken significant steps this year to restrict its trade in wild animals, which are believed to harbor the virus.
With those potential sources of disease kept in check, some scientists believe laboratory infections now pose the greatest risk for a comeback by the disease. After conducting a thorough review of the cause of the Chinese outbreak, the WHO may devise more-detailed safety guidelines for all labs handling the virus.
Still, the WHO lacks the ability to enforce safety standards, and even the best-equipped labs provide no guarantees against human error. "No matter what kind of technical safeguards are put in place, labs are going to be operated by human beings, who may feel sick or may have had a bad night, and who could have a lapse of concentration" that leads to infection, Mr. Thompson said.
Among the eight cases, two of the people had been working at a Beijing laboratory in the China Center for Disease Control's Institute of Virology. SARS-related research has been conducted in the lab. One of the two ill lab workers is a 26-year-old graduate student, a Ms. Song from Anhui province, who worked at the lab from March 7 to March 22. She developed a fever March 25 and was confirmed as a SARS case on Friday. She is being treated at the No. 1 Hospital of Anhui Medical University, according to the Ministry of Health.
Ms. Song was treated at Beijing's Jiangong Hospital from March 29 to April 2, where the nurse, Ms. Li, was apparently infected. Ms. Song's mother, who cared for her after March 31, developed a fever April 8 and died April 19. She was declared a suspected SARS carrier after her death. The other laboratory worker is a Mr. Yang, a 31-year-old postdoctoral student. He reported a fever April 17 and was admitted to Ditan hospital in Beijing on April 22. He is classified as a suspected case. Mr. Yang was doing some SARS-related research at the lab, according to Bi Shengli, the institute's vice-director.
Ms. Song was working as an intern and conducted experiments unrelated to SARS, Mr. Bi said. Officials with the Beijing Center for Disease Control said Ms. Song had been researching adenovirus and syncytial virus.
"We're disappointed by what seems to be a failure of biosafety guidelines in the labs," Mr. Thompson said. "One of the features of a biosafety guideline is that if workers become sick, it should trigger an alarm, and that apparently didn't happen." The virology institute has been sealed off since April 23 and will remain so until May 7, according to the Ministry of Health. Mr. Bi said about 180 institute personnel were put under isolation in a rural area of Beijing.
SARS复发引起实验室安全担忧
看似从中国一个实验室肇始的非典型肺炎(SARS)疫情反映出该事件一个危险的转变：去年在扫除该病毒过程中起著先锋作用的医疗科学界现在首当其冲地面临SARS卷土重来时的风险。
中国昨天报告了四例新的疑似严重急性呼吸道综合症(SARS, 俗称：非典型肺炎)病例，此外周五宣布有两人被确诊、另有两人为疑似病例。这四例新病例都是同某确诊病人有过密切接触的人，这位确诊病人是北京一位20岁的李姓护士。
安徽省尚无新的SARS感染病例报告，上周五宣布的疑似病例中有两例发生在安徽。不过北京的病例更加让人对感染SARS感到担忧，因为再过几天，成千上万的人将在五一劳动节挤上火车、公共汽车和飞机外出旅游，这使遏制SARS扩散的难度加大。
日内瓦的世界卫生组织(World Health Organization,WHO)发言人迪克?汤普森(Dick Thompson)说，"这四个病例意味著我们现在进入了第三代传播期，病毒从一位26岁的实验室工作人员身上传染给了他的护士，再由护士传染给了她的家人"以及另外一位同一家医院病室内的人。同北京和安徽的疑似病人有过接触的300多人目前已被隔离。
如果这些病例最终确认是源自北京实验室的不当操作（北京的官员如此认为），这将是2003年年中SARS国际传染消退之后所爆发的第三波、而且也是最严重的复发事件。去年在新加坡和台湾发生的实验室失误事件导致两人感染。这两例病例均被控制，而且病人最终康复，但最近中国发生的感染被认为已至少引起该病毒二次传染到六个人，其中一人已经死亡。
应中国政府的要求，世界卫生组织正对汤普森所谓的"严重"事件展开调查。WHO调查组的第一批成员定于今天抵达北京。除了生物安全专家，还有流行病学家赶来北京帮助中国卫生当局追踪可能同感染病人有过接触的人。
汤普森说，"公共卫生受到的威胁依然很小而且有限。"但他表示WHO不能确认该病毒在被控制20天后是否不再有新的病例出现。20天是SARS病毒最长潜伏期的两倍时间。
这些病例将不安的焦点集中在了处理SARS病毒的实验室的安全标准和行为上。SARS病毒去年爆发后引起全球774人死亡，8,000多人被感染，但在科学家、保健工作人员以及卫生官员的努力下，SARS在人与人之间的传播链条已被截断。中国今年还采取了严厉措施限制野生动物买卖，因据信野生动物是该病毒的藏身之地。
由于SARS病毒的那些潜在来源已被严格控制，一些科学家相信，实验室感染现在是该病毒卷土重来的最大风险所在。在对中国疫情爆发来源进行全面检查后，WHO可能会制定一套针对所有处理SARS病毒的实验室的更为详细的指引。
不过，WHO依然缺乏执行安全标准的能力，甚至那些设备最好的实验室都不能保证不出人为错误。汤普森说，"不管实行什么样的技术安全标准，实验室都是由人来操作的，而人们可能会因感觉不适或晚上没睡好，或注意力分散"引起感染。
在这八个病例中，有两人在中国疾病控制中心病毒病所的北京实验室工作。有关SARS的研究工作在这个实验室进行。两位犯病的实验室工作人员中，一位是来自安徽的26岁宋姓研究生，她3月7日至3月22日期间在该实验室工作。3月25日她出现发烧，并在上周五确证为SARS病例。据中国卫生部称，目前她在安徽医科大学第一附属医院(No. 1 Hospital of Anhui Medical University)就诊。
宋女士在3月29日至4月2日在北京的健宫医院就医，李姓护士显然是在此感染的。宋女士的母亲在3月31日去医院照顾她，然后在4月8日出现发烧症状，4月19日身故。宋女士的母亲死后被宣布为疑似SARS携带者。另外一位在实验室工作的是31岁杨姓博士后学生。他报告4月17日发烧，并在4月22日住进北京地坛医院。他被定为疑似病人。据病毒病研究所副所长毕胜利称，杨当时正在该所做与SARS有关的研究。毕胜利称，宋是在该所实习，她进行的实验和SARS无关。
北京疾病控制中心的官员称，宋研究的是腺病毒和多核体病毒。 汤普森说，"我们对于实验室可能未能遵守生物研究安全规定感到失望。生物研究安全规定的一个特点是如果工作人员感到不适，它应该拉响警报，显然并没有警报发生。"中国卫生部称，这个病毒研究所自从4月23日一来就被封锁，并将持续到5月7日。毕胜利说，该所大约180多名人员已被隔离在北京郊区的某个地方。
