The virus known as Middle East Respiratory Syndrome Coronavirus, or MERS -- which has so far killed 38 of the 64 people known to have been infected with it -- has been especially aggressive in Saudi Arabia, where, as of Wednesday, health officials had reported 49 cases and 32 deaths.
Now a team of U.S. and Canadian scientists has teamed with Saudi health officials and others to report on how MERS spread through four hospitals in the eastern part of the country, infecting 23 patients and healthcare workers and killing 15.
Writing in the New England Journal of Medicine, Johns Hopkins epidemiologist Dr. Trish Perl and colleagues from other institutions described the outbreak, which took place in April and May. Sifting painstakingly through medical records compiled by their Saudi hosts and other data, Perl and the team reconstructed how the virus spread from patient to patient, discovering that it passed from person to person in dialysis and intensive care units -- and also when patients were transferred between hospitals.
Through what Perl called "the CSI part" of the research, they showed that the virus is able to pass from person to person to person. "This moves it to the next level," she said, in an interview. "We have ongoing propagation."
Perl's visit came as Saudi officials were drawing some criticism about their response to MERS -- a virus that is similar in many ways to SARS, which killed 774 people about a decade ago. There is much researchers still don't know about MERS, including how dangerous it will ultimately be for people, what animals are its natural host and what other animals might harbor the virus and pass it along to people.
The new research doesn't shed light on those questions, but will help health officials battle the disease. The team was able to calculate the incubation period, or how long it took for infections to progress to illness (median 5.2 days), and the serial interval, or time between cases in the chain of transmission (median 7.6 days.)
Knowing how long it takes for the virus to infect, sicken and pass among people will help hone guidelines for quarantines and other protective measures in healthcare facilities, Perl said.
She said she also hoped the team's experience of being invited to work in Saudi Arabia, which she described as "an honor," would help forge ties between local officials and health workers in the Middle East and the global health community. Collaboration could speed development of better diagnostics and rigorously defined clinical approaches for patients with MERS, she added.
"We need a research agenda that's an international agenda," she said.
So far, most MERS cases have occurred in the Middle East, and the handful of cases in Europe have occurred in patients with links to the region. On Monday, another group of researchers reported in the Lancet on a MERS patient who traveled from Abu Dhabi to Germany for treatment but died on day 18 of his illness.