Middle East Respiratory Syndrome (MERS) patients may require longer quarantine if doctors hope to halt the spread of the potentially deadly disease, according to a report issued by French physicians on May 29.

Published in the journal Lancet, the report is the result of an analysis by the authors of two cases of the virus in France. The cases include a 64-year-old man who began exhibiting symptoms after a trip to Dubai, United Arab Emirates, and an individual who began showing signs after having had contact with the first patient.

Besides offering substantial proof of the ability of the virus to travel between people, the study’s findings “suggest,” according to the researchers, that the virus’s incubation period could be as long as nine to 12 days, a longer period than was previously recorded.

Knowing this, the doctors write, should have “clinical implications for the duration of quarantine” for patients who test positive for the disease.

According to the World Health Organization (WHO), as of May 29, the United Nations organization had been made aware of a total of 49 laboratory-confirmed cases of infection with MERS, 27 of which had died, including the French patient who visited the United Arab Emirates.

In a speech on May 27, WHO Director-General Dr. Margaret Chan said that, of everything going on in the world, MERS is her greatest health concern, calling the ongoing outbreaks “alarm bells” and stating the virus “is a threat to the entire world,” according to USA Today.

Furthermore, according to the Centers for Disease Control and Prevention (CDC), which has been working closely with the WHO as well as other partners to better understand the risk posed by the disease, genetic sequence analyses have shown that this new virus is different from any other known human coronaviruses.

The virus was first isolated from a patient with acute pneumonia and renal failure in summer 2012 in Jeddah, Saudi Arabia, according to a May 15 CDC report; however, the onset of the disease, according to the U.S. agency, can be traced back to an even earlier time when, in April of 2012, a cluster of pneumonia cases in health care workers arose in an intensive care unit in a hospital in Zarqa, Jordan.

At that point, two people died, both of whom were confirmed to be infected with the novel coronavirus.

In the end, the WHO does not advise special screening at points of entry in regard to the virus, nor does it advise any travel or trade restrictions.