Study Reveals How New Respiratory Virus Spreads

Infectious-disease experts went to Middle East to gather information on often deadly MERS virus

By Robert Preidt

HealthDay Reporter

WEDNESDAY, June 19 (HealthDay News) -- The new respiratory virus responsible for an ongoing outbreak in the Middle East poses a serious risk to hospitals because it is easily transmitted in health care facilities, according to a new study.

A team of infectious-disease experts traveled to Saudi Arabia to investigate the spread of the Middle East respiratory syndrome coronavirus (MERS-CoV) in four Saudi hospitals in May. They concluded that the new virus was even more deadly than the related SARS (severe acute respiratory syndrome) virus that caused an outbreak in Toronto hospitals in 2003.

Not only is MERS-CoV easily transmitted from patient to patient, but also from hospital to hospital when sick patients are transferred, according to the study, which was published online June 19 in the New England Journal of Medicine.

"Our investigation showed some surprising similarities between MERS and SARS. Both are very deadly viruses and easily transferred between people, and even between health care facilities," team member Dr. Trish Perl, senior hospital epidemiologist for Johns Hopkins Medicine and a professor at the Johns Hopkins University School of Medicine, said in a Johns Hopkins news release.

At the time of the investigation, 23 people in Saudi Arabia had been infected with MERS-CoV and 11 had died of the virus. The death toll in that country now stands at 32, with 49 people infected, according to the most recent report from the U.S. Centers for Disease Control and Prevention.

In Saudi Arabia, swift action by local health officials to monitor the disease -- including rapid detection, isolation and treatment of infected patients -- has largely helped stem the outbreak, Perl said.

In addition, hospitals have ramped up infection control by introducing stronger disinfectants, requiring health care workers to follow strict procedures (such as wearing masks, gowns and gloves), giving infected patients private rooms and providing masks for uninfected patients in the vicinity.

The investigators also found that the death rate for MERS was much higher than for SARS: 48 percent versus 8 percent, respectively. But the MERS death rate may decrease if more cases -- including patients with mild symptoms -- are identified, the experts said.

The time from MERS exposure to the first signs of infection is about a little more than five days. Symptoms include coughing, shortness of breath, fever and vomiting. It took an average of about eight days for the virus to spread from one person to another, the findings showed.

"The story of how this outbreak occurred and how this virus was transmitted became very clear once we started to lay out the evidence and saw that one infected patient had been in the hospital at the same time as another infected patient, and this patient was transferred to another hospital, where another patient became infected shortly thereafter," Perl said in the news release.

Knowing this information is critical to halting future MERS outbreaks because it reveals how long health officials have to act before a person exposed to the virus begins to show symptoms and when people they infect also start to show symptoms, the researchers said.

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