SARS epidemic

Epidemic

Date: November, 2002, to July, 2003

Place: Worldwide, but primarily Asia and Canada

Result: 8,422 reported cases and 916 known deaths

Severe acute respiratory syndrome (SARS) was the first major health crisis of the twenty-first century. SARS is one of the fastest spreading and most virulent diseases known. It occurs as a severe form of pneumonia and may result in death in patients with preexisting health issues or those who seek treatment too late. From November 27, 2002, to July 14, 2003, SARS infected 8,422 victims worldwide and caused 916 known deaths. In China alone, the source of the outbreak, there were 5,327 cases, with 349 people dying of the disease.

Prior to the identification of SARS, an occurrence of an atypical pneumonia was reported in Guangdong Province, China, in November, 2002. By February, 2003, 24 provinces in China reported cases of atypical pneumonia. A Guangdong physician treating patients suffering from this pneumonia traveled to Hong Kong and checked into a hotel in Kowloon on February 21, 2003. By March 4, he was dead, and 12 guests of the hotel housed on the same floor were infected even though they had had no direct contact with him. Hong Kong is a major transportation hub for all Asia. In a matter of days, these 12 people spread SARS throughout Hong Kong, Canada, Singapore, and Vietnam. By the end of March, 2003, cases of SARS were diagnosed in Italy, France, Ireland, Germany, Switzerland, Spain, Thailand, Malaysia, Taiwan, the United Kingdom, and Romania; by the end of April, cases appeared in the United States, Australia, Brazil, India, Mongolia, South Africa, Kuwait, the Philippines, Sweden, Indonesia, and South Korea. During May, cases appeared in New Zealand, Colombia, Finland, Macao, Russia, and Taiwan. It would take until mid-summer 2003 to contain and control the SARS outbreak through quarantine, isolation, and travel restrictions. In an age of globalization and rapid transportation between nations—air travel to any location on the planet in less than 24 hours—the SARS outbreak demonstrated the severe threat of pandemic posed by new and rapidly emerging communicable diseases.

The Nature of SARS. SARS is an infectious respiratory illness known as an atypical pneumonia. Typical pneumonia is primarily caused by bacteria such as streptococcus, while atypical pneumonia results from viruses such as influenza or specialized bacteria such as chlamydia or mycoplasma. All pneumonia results in stress to the respiratory system. In cases of SARS, however, not only is the respiratory system affected but other organs are involved in the infection as well, especially the liver.

The onset of SARS is marked by a rapidly raising fever and dry cough, followed by shivering, dizziness, lethargy, muscle ache, vomiting, skin rashes, diarrhea, sore throat, and upper respiratory distress. In some patients, these symptoms may be followed by difficulty in breathing and rapidly progress to a severe form of pneumonia resulting in death when the heart and other organs fail from oxygen deprivation. The causal virus of SARS is a unique coronavirus. Coronaviruses are one of the viruses responsible for influenza and about 20 percent of common colds. Coronaviruses can survive in an exposed environment for up to three hours and can infect humans as well as birds, cows, rabbits, dogs, cats, mice, and pigs.

The SARS virus is spread by direct person-to-person contact or contact with aerosolized respiratory secretions from coughing, sneezing, or breathing. In addition, droplets or respiratory secretions that end up on a victim’s hands from rubbing the mouth or nose can also transfer the infection to touched objects. A vaccine for SARS is still in the experimental stage, but patients diagnosed and treated in the early stages of an infection usually recover. Treatment typically includes steroids and broad-spectrum antiviral drugs, and in some cases supplemental oxygen and assisted ventilation.

Outbreak and Control. Coronaviruses and influenza are widespread in the environment and exist in a range of animal hosts, especially birds and pigs. Certain avian strains of influenza have demonstrated the ability to mutate and cross species barriers to infect humans. Southern China is home to massive commercial-scale poultry and pig industries and has a history of spawning new, highly virulent strains of influenza. In the last four decades of the twentieth century, at least four new strains of influenza spread globally from China. The huge number of poultry and pigs contained on these commercial farms provides an easy opportunity for any virus, mutated or otherwise, to find an available host and multiply readily. Animal handlers, cooks, and fresh food market vendors may all have first-line contact with an infected animal. If a cross-species mutation of an animal virus occurs, these people are the first to be exposed.

On November 16, 2002, in Foshan, China, a chef specializing in the preparation of exotic meats was diagnosed and hospitalized with an atypical pneumonia. The patient was able to recover, but four members of the hospital staff who treated him soon showed signs of the same infection. In a matter of days, a number of food handlers and vendors from Guangdong Province’s street markets were hospitalized with a similar pneumonia. Chinese medical authorities suspected that the patients were suffering from a new strain of influenza, but tests for influenza came back negative, as did tests for anthrax and plague. Tests did indicate several different respiratory pathogens present in lung secretions, including metapneumovirus and chlamydia.

By February, 2003, the World Health Organization (WHO) was notified of this unknown respiratory illness infecting 305 patients and resulting in at least 5 deaths in Guangdong, China. All reports of atypical pneumonia or other symptoms indicative of a new strain of influenza reported to WHO are given high-priority status for tracking and action. The outbreak of the illness remained localized around Guangdong, with the majority of victims being food handlers working in open-air markets or health professionals who dealt with infected patients. The epidemic seemed to reach its peak in early February, and then cases began to decline. This all changed on February 21, 2003, when a physician from Guangdong traveled to Hong Kong and checked into the Metropole Hotel. The physician had been treating patients with SARS, and at the time of his arrival in Hong Kong he was already symptomatic of the infection. The physician fell ill and was taken to Prince of Wales Hospital, where he eventually died after infecting many of the hospital’s staff and patients.

Within days, 12 guests staying on the same floor of the hotel as the physician were diagnosed with the Guangdong respiratory illness. One of the infected guests, an American businessman, traveled to Hanoi, carrying the disease with him to Vietnam; he was asymptomatic at the time of his travel but on February 26, 2003, was admitted to a Hanoi hospital and put under the care of a WHO physician, Dr. Carlo Urbani. Another unknowingly infected guest traveled to Singapore; she was hospitalized soon after her arrival, where she infected medical staff and other patients. Two unknowingly infected guests flew to Canada, one to Vancouver and the another to Toronto. Guests in China who became symptomatic while still at the hotel were admitted to Hong Kong hospitals, where again many of the staff members and patients were exposed to the disease. The important fact of the Metropole Hotel outbreak is that none of the infected guests had any direct contact with the visiting Guangdong physician.

Because of SARS’ incubation period of 2 to 14 days, Hong Kong’s cosmopolitan setting, and the ability of unknowing carriers to serve as a vector in a matter of hours via air travel, infected travelers were able to seed local epidemics throughout the world. The disease carrier from Singapore was eventually linked to more than 100 SARS cases in Singapore; the Toronto carrier initiated an outbreak in a Toronto hospital resulting in 132 cases and 12 deaths.

On March 15, 2003, WHO issued a statement that severe acute respiratory syndrome was a global health threat because it was spreading so far and so quickly. On the same day, Air China Flight 112 flew from Hong Kong to Beijing, and 22 passengers and 2 flight attendants fell ill, beginning a SARS outbreak in Beijing. The Beijing outbreak resulted in the most cases and largest number of SARS-related deaths in China.

During the last week of March, 2003, a second outbreak of the illness in Hong Kong began when an infected victim with renal disease passed the disease throughout the Amoy Gardens apartments. The Amoy Gardens is a densely populated housing development. Many of the floor drain traps were not sealed, and many of the bathrooms were openly connected to the sewer pipes. Virus-heavy droplets coming from the infected apartment easily spread through the drains. Initially, SARS was thought to be transmitted only through direct person-to-person contact with respiratory secretions. Because many cases suggested no direct contact between victims, however, environmental transmission was suspected as an additional vector. The Amoy Gardens cases tended to confirm this conclusion, as 213 residents fell ill within the apartment complex. The Hong Kong government first isolated the complex and then relocated residents to two “holiday camps” for quarantine. That same week, a public housing complex across the street from Amoy Gardens reported a new outbreak of 30 cases and was immediately isolated.

Dr. Carlo Urbani, the Italian epidemiologist working with WHO in Hanoi who first named the disease “severe acute respiratory syndrome,” became a victim of SARS and died on March 29. In memory of his research, WHO formally designated the disease “SARS” on April 16. By the end of April, 2003, SARS was identified in 14 countries around the globe, with more than 1,300 cases and 50 known deaths; by the end of the month, SARS was reported contained in Vietnam, and new cases in Singapore and Hong Kong were diminishing. Unfortunately, a new outbreak of SARS was reported in Taiwan, where a misdiagnosis resulted in the disease spreading widely throughout regional health care facilities. Random cases continued to appear in China, but the second largest outbreak was in Toronto. The traveler landing in Vancouver from Hong Kong arrived showing signs of infection, was quickly isolated, and recovered without infecting others. In Toronto, the carrier from Hong Kong was able to infect family members and eventually a number of health care providers. By mid-March, Toronto public health officials alerted the public to the outbreak of an atypical pneumonia. Before the end of May, nearly 7,000 cases of voluntary quarantine were imposed on suspected patients or carriers to stop the outbreak in and around Toronto.

Throughout the world, stringent control measures were taken to stop the spread of SARS. Most important, airport and border guards began screening travelers for fever, and strict isolation and quarantine protocols were instituted in areas reporting SARS symptoms. By mid-May 2003, the number of new cases of SARS diminished, and at that time researchers in Hong Kong discovered the genetic sequencing of a coronavirus found in civet cats to be 99 percent the same as the SARS virus. On May 24, 2003, the Chinese government temporarily banned importing exotic meat from civet cats, a popular Guangdong Province delicacy. It is likely that the original reported human infection of SARS, the exotic meat cook from Foshan, had contracted the disease from preparing civet cat.

Besides the human toll, SARS inflicted economic and political damage. During the months of outbreak, Asian countries saw an estimated financial loss of $28 billion. For the first time in its history, WHO issued an advisory suggesting that travelers avoid parts of the world infected with a disease. Airlines cut 10 percent of their flights from North America to Asia, and some countries saw a drop of more than 60 percent in tourism. In Canada, China, and the United States, sporting events, public gatherings, film productions, religious services, and parades were all canceled as a result of concerns about SARS. After the SARS outbreak was contained, public health officials and political leaders, especially in China, were accused of cover-ups and mismanaging the crisis to avoid economic disruption.

An interesting footnote to the SARS legacy occurred in June, 2006, when Chinese researchers revealed that at least one of the reported SARS deaths in China during 2003 was actually the result of H5N1 avian influenza, raising the possibility that other cases attributed to SARS may have actually been human cases of H5N1 bird flu and that the Chinese government covered up the possibility that two pathogens were experiencing simultaneous outbreaks in China.

Bibliography

Kleinman, Arthur, and James L. Watson, eds. SARS in China: Prelude to Pandemic? Stanford, Calif.: Stanford University Press, 2006.

Koh, Tommy, Aileen Plant, and Eng Hin Lee, eds. The New Global Threat: Severe Acute Respiratory Syndrome and Its Impacts. River Edge, N.J.: World Scientific, 2003.

Leung, Ping Chung, and Eng Eong Ooi, eds. SARS War: Combating the Disease. River Edge, N.J.: World Scientific, 2003.

Levy, Elinor, and Mark Fischetti. The New Killer Diseases: How the Alarming Evolution of Mutant Germs Threatens Us All. New York: Crown, 2003.

Schmidt, A., M. H. Wolff, and O. Weber, eds. Coronaviruses, with Special Emphasis on First Insights Concerning SARS. Boston: Birkhäuser Verlag, 2005.