SARS
The Agent
SARS (severe acute respiratory syndrome) is a newly emerged infectious disease that is characteristically severe, has pneumonia-like symptoms, and is often fatal. It is caused by a virus called SARS-associated coronavirus (SARS-CoV). SARS was first recognized in Guangdong Province, China in November of 2002. It then spread extremely rapidly to Hong Kong, Vietnam, China, Singapore, Taiwan, and Toronto, Canada in the early half of 2003. Altogether, more than 8,000 people were documented to have had SARS and over 800 died. SARS-CoV was transmitted from person to person mainly through respiratory droplets that are produced when a person sneezes or coughs and also through direct contact with a surface contaminated with infected respiratory droplets. More recently, several infections were reported that resulted from lapses in high-containment laboratory procedures, but did not spread into the general population.
Courtesy: CDC/
James Gathany
The global scientific response to SARS was unprecedented. Within weeks after the respiratory disease was first reported, the agent that causes the disease was identified, diagnostic tests were developed, and the entire genome of the virus was sequenced. Furthermore, epidemiologists gathered evidence that the first people infected had had contact with wild game in the markets of Guangdong Province in China. It is likely that these individuals were infected through direct contact with infected animals. These animals were found to harbor very closely related coronaviruses. Later, the virus is thought to have mutated and adapted to its human host, and consequently human-to-human transmission became more efficient, setting off the SARS epidemic. Fortunately, the SARS outbreak was short-lived, and public health containment procedures and coordinated responses proved effective in preventing further spread of the disease.
Courtesy: CDC/
Dr. Fred Murphy
SARS-CoV is a newly identified member of a class of viruses known as coronaviruses and is the only known member of this virus family to cause death or severe respiratory disease in humans. The other viruses in this group cause mild upper-respiratory infections in humans and are associated with respiratory, gastrointestinal, and neurologic diseases in animals. Coronaviruses were named for their appearance under the microscope – they have a spiky or crown-like (corona) appearance. One reason that SARS-CoV might be more lethal than other coronaviruses is that it appears to interfere with an enzyme system in humans that is critical for regulating body fluid balance. Therefore, the virus could disrupt normal functioning of the lungs by blocking this enzyme system and allowing fluid to leak into the air sacs of the lungs, resulting in severe respiratory illness.
The Problem
Although there are currently no known human cases of SARS, it is still possible that another outbreak of SARS could occur. SARS-CoV still likely lurks in an animal host in the wild, and human contact with this animal(s) could again spark a SARS epidemic. Two groups of scientists have now reported that the Chinese horseshoe bat is likely to be the animal that is the hiding place of the SARS virus. Genetic analysis of the virus in bats showed that it is closely related to the human SARS virus, although it is still not clear how the SARS virus was transmitted from bats to humans. The Chinese horseshoe bat is not found in the United States.
Despite the large amount of knowledge that has been gained about SARS-CoV following the outbreak, there are still no vaccines or antivirals approved for preventing or treating SARS-CoV infections.
The Research
Investigators in the Department of Molecular Virology and Microbiology (MVM) at Baylor College of Medicine (BCM) have been awarded funds for development of a SARS-CoV research program as an expansion of the existing Virus Respiratory Pathogens Research Unit – a contract arrangement between BCM and the National Institutes of Health (NIH).
The research program on SARS-coronavirus infection and disease within MVM focuses on the
- Pathogenesis of SARS-CoV infection and disease
- Development of a virus-like particle vaccine for SARS
- Clinical trials of SARS vaccine
This research is being conducted by MVM researchers at the Biosafety Level 3 (BSL-3) facilities at the University of Texas Medical Branch (UTMB) in Galveston. MVM researchers have also established collaborations with investigators in Beijing, China. Beijing is where SARS patients received medical care during the 2003 epidemic and will receive care if the disease returns again. This allows MVM researchers access to large numbers of people who survived the previous SARS epidemic and, possibly, to new SARS patients.
The MVM faculty involved in SARS research are Dr. Robert Couch, Dr. Wendy Keitel, and Dr. Innocent Mbawuike.
For more information: