about Epidemiology & the department

Epidemiology academic information

Epidemiology faculty

Epidemilogy resources

sites of interest to Epidemiology professionals

Last Updated

01 May 2003

Source: Newsday, May 1, 2003

New Cause of SARS Found

Some clusters may have resulted from gastrointestinal cycle

By Laurie Garrett, Staff Correspondent

Beijing -- Scientists have concluded that severe acute respiratory syndrome may not be just a respiratory disease: Some clusters of cases may have resulted from an entirely different, gastrointestinal cycle of the virus.

The findings don't offer optimism for gaining control of the epidemic. Using masks and other means to guard against exhaled droplets is one thing; blocking fecal contamination of water supplies and food processing, especially in poor countries, is quite another. The leading theory for the Amoy Gardens outbreak in Hong Kong focused on sewage backups into apartment toilets, where the virus may have become aerosolized.

"We now realize that we see two different clinical courses of this disease depending on the port of entry" for the virus, into the body, the World Health Organization's top virologist Dr. Klaus Stohr said in a telephone interview from WHO's Geneva headquarters. "Feces transmission is definitely a concern." In other words, inhalation of the virus results in a respiratory disease, whereas transmission via fecal contamination causes gastrointestinal symptoms.

Studies of people who live in the Amoy Gardens apartment complex in Hong Kong, where more than 300 people contracted SARS, show that many patients experienced primarily diarrhea and gastrointestinal illness. Live viruses were present in the patients' feces, University of Hong Kong SARS researcher Dr. Yuen Kwok-yung said in an e-mail interview, and overall, the Amoy Gardens patients were far sicker, and younger, than other SARS cases. Researchers have determined that they shed live SARS viruses for as long as 28 days.

Whether the virus can be shed for even longer "is still under investigation," Yuen said.

Yuen's team has managed to grow SARS viruses from fecal samples. In addition, Hong Kong physicians report that 12 "recovered" SARS patients, whose respiratory symptoms had disappeared, have experienced relapses, a sign the virus managed to hide from the patients' immune systems.

"It is well known that coronavirus is a cause of diarrhea in animals and occasionally in humans, so shedding in stool should not come as a surprise," Dr. Julian W. Tang of the Department of Virology at the University College London Hospitals, said via e-mail. "With SARS, we obviously need more follow-up studies in recovered patients before any further conclusions can be drawn. But first we need to stem this current pandemic."

Fecal spread poses a serious concern in poor regions, such as provincial China. In such areas dysentery and cholera, both fecally transmitted agents, spread in unfiltered water supplies and on unwashed hands and handled foods.

World Health Organization teams are trying to determine how long the virus can survive outside the human body.

Environmental scientists are combing Hong Kong, trying to scrape live viruses off doorknobs, elevator buttons, banisters and other surfaces. At room temperature, the virus can survive more than 24 hours, Stohr said, though the concentration declines during that time, and lab studies show it surviving for half an hour at temperatures as high as 132.8 degrees Fahrenheit.

"We all remain worried that what we see is an incomplete picture," Stohr said.

In Beijing, where another 101 SARS cases and nine deaths were reported Wednesday, this question of fecal transmission is hardly academic. Acting Mayor Wang Qishan, appointed last week after the cover-up of the SARS outbreak had become clear, said in a news conference that, "with respect to some Amoy-like situations, according to my information such cases do exist" in Beijing.

For the first time Beijing authorities released a list of 11 quarantined buildings in which SARS transmission has occurred on a significant scale. Officials also published a district-by-district breakdown of the city's cases as part of Wang's pledge to provide "absolute transparency".

The list reveals that more than half of Beijing's cumulative 2,705 confirmed and suspected cases are in one district, Haidian. They include students, faculty and staff of two universities that have been under quarantine for a week.

At Northern Jiaotong University, popularly known as Transportation University, a quarantined staff member who asked not to be identified said in a telephone interview she wasn't scared, but added, "I have no choice I have to work here."

She did admit to being "a little bored, and fatigued," after a week in quarantine. SARS has spread in the dormitories, and "if one gets infected, then they all [dorm residents] get infected all the others are in danger."

So far, student cases have been confined to three dorm buildings.

Wang's openness was in stark contrast to the denial six days ago by a health official that any SARS outbreaks had occurred in the city. Wang also spoke about the city's overwhelmed health care system, saying Beijing has 32,000 physicians and 34,000 nurses but only 3,000 of them "know very much about respiratory diseases. We find that we're ill-prepared in terms of the knowledge of our doctors and nurses, and our medical equipment."

Some 1,200 health care workers from the People's Liberation Army joined the civilian medical response Wednesday, and the Central Committee of the Communist Party approved drafting doctors from all over China. Wang said that he hoped the mobilization would help lower Beijing's SARS death rate, which he did not specify.

Physicians have noted indications of fecal spread of SARS in the city. Wang said that waste disposal of medical supplies and patient bedding and other materials is a primary concern, and one that has compelled moving SARS patients out of some of the city's lower quality hospitals.

He also confirmed reports of violence in the rural villages that ring Beijing. There, villagers have fought to prevent urban residents from entering their communities and possibly bringing SARS. Every villager has been supplied with a thermometer, Wang said, and is now required to take his or her temperature daily, providing village leaders with the results. All funerals and weddings are being postponed in those communities, he said.

Wang also said the first patients were ready to move into the new 1,000-bed hospital built on the northern outskirts in the past eight days.

Nationwide, the reported number of deaths reached 159, with cases at 3,460.