Maryland health officials received the materials last month and have not had to use them, said Robert Myers, director of the state public health lab.

"The reason we are taking this very seriously is Europe has already experienced at least four distinct episodes of importation" from the Middle East, said Dr. Mark Pallansch, director of the CDC's viral diseases division. "These episodes tell us the risk is not zero. We have to expect that an importation could occur, and we need to be prepared for that eventuality."

The disease is just the latest infectious outbreak keeping Perl busy. She said she is pulled into such investigations around the world every couple of years, along with visiting hospitals around the country with infection problems.

She has spearheaded or been involved in recent investigations into the national outbreak of fungal meningitis linked to tainted steroid injections and annual flu outbreaks. When dozens of workers got sick at the Johns Hopkins at Keswick offices in Hampden in February, they were asked to cooperate with Perl's inquiries to determine the source of the illnesses.

There is still much to be learned about the MERS outbreak, she said. For example, while the study found that nearly two out of three people infected with the disease died, it is possible that milder cases might have gone undetected.

"There's no question it's a fact, but I don't know whether it's reality," Perl said.

MERS outbreak

The disease: Middle East Respiratory Syndrome is a virus similar to SARS that causes upper respiratory tract infections, thought to be passed via coughing

Case count: 64 infections and 38 deaths across eight countries in the Middle East, Europe and Africa

Symptoms: Severe acute respiratory illness with cough, fever and shortness of breath

Prognosis: Deadly in 65 percent of those infected as part of a cluster in Saudi Arabia that was the subject of a study in The New England Journal of Medicine

Response: With no known treatment, health officials are focusing on preventing spread of disease within health care settings, recommending quarantining patients and preventive measures such as wearing masks and gloves