On March 26, a patient in a Munich hospital was the first person in Germany to die of a new SARS-like viral infection called MERS-CoV, for Middle East Respiratory Syndrome coronavirus.
This deadly new virus was first reported in a handful of patients in Jordan, Saudi Arabia and Qatar in the spring of 2012. As of June 19 this year, 64 people have had confirmed MERS infection and 38 of them have died. A new study in the journal Lancet examines evidence from the Munich patient and others in order to learn more about the virus and how it has spread.
"There is some good news," wrote Dr Clemens-Martin Wendtner of the Department of Hematology at Klinikum Schwabing and an author in the Lancet study, in an email from the MERS-CoV conference organized by the World Health Organization (WHO) in Cairo. The virus appears to be more reliably detectable in the lower respiratory tract - deep in the lungs - than in the upper tract (through a nasal swab) or in the stool, blood or urine. That means a more invasive diagnostic test is needed, but also that the virus probably does not spread as easily as SARS did. In SARS, patients frequently had diarrhea and the stool spread the virus.
The other good news, Dr Wendtner added, is that the MERS does not seem to be mutating into a more aggressive form - at least not yet.
A decade ago, SARS emerged quickly and infected some 8,000 people, killing 774 of them of acute respiratory distress. MERS, which is closely related to SARS both genetically and symptomatically, seems to be more deadly, with a mortality rate of over 50%. However, some milder MERS cases may have gone undetected, so the mortality rate may not be as high as it appears.
MERS is also much less well understood than SARS at an analogous stage of the outbreak. Because of that, WHO head Margaret Chan recently called MERS her greatest global health concern.
"Any new disease that is emerging faster than our understanding is never under control," Chan said in her closing remarks at the 66th session of World Health Assembly in May. "We do not know where the virus hides in nature. We do not know how people are getting infected. Until we answer these questions, we are empty-handed when it comes to prevention."
The Lancet study is one of several in recent weeks that attempt to answer some of those questions. The Munich patient was a 73-year old man with a chronic blood disease called multiple myeloma. He was from the United Arab Emirates, and had recently tended one of his camels that was sick. On March 10, he was hospitalized in Abu Dubai two days after becoming suddenly ill, and was then transferred to the Klinikum Schwabing in Munich with severe acute respiratory infection on March 19. He rapidly developed kidney failure and died of septic shock 10 days later.
The patient fit what appears to be a typical profile of those infected with MERS to date. All these patients either lived in one of the Middle East countries (many had close contact with camels), or had recently traveled to it, or contracted MERS from a patient who had "imported" it to Europe from the Middle East.
In addition to the Middle East connection, the typical MERS patient is older, predominantly male, and has some underlying disease or compromised immune system. In contrast, SARS infected slightly more women than men, and more young adults and children.
Perhaps veils and other societal norms in Middle Eastern countries reduce female exposure to the virus, or it could be that men from the region preferentially eat food that may be contaminated with the virus, explained Dr Wendtner. It is also possible that the men have more contact with camels or another animal that might be a reservoir for the virus.
For SARS, the virus was traced back to a bat coronavirus. The bats infected civet cats, which then infected people. MERS is also similar to a bat virus. One suspected carrier species is the Egyptian tomb bat (Taphozour perforatus) that is endemic in Western Saudi Arabia where many cases were observed, Dr Wendtner noted. A very preliminary analysis found an antibody to the MERS-CoV in the blood of camels, suggesting camels could be conduits from bats to humans.
Of the 11 cases reported in four European countries so far, three had been transferred from the Middle East for care, three became sick after traveling to the Middle East, and five contracted it from one of those patients, according to the European Center for Disease Prevention and Control's (ECDC) June 18 Updated Risk Assessment.
A report in the New England Journal of Medicine that came out the same day as the Lancet study examines hospital cases in Saudi Arabia, where 49 confirmed MERS infections and 32 deaths have occurred as of June 19. The researchers found that the average time that it takes to develop symptoms after exposure to MERS was about five days - although the incubation period may be as long as 14 days.
The Lancet researchers also attempted to construct a timeline and evolutionary tree of the MERS virus by comparing viral DNA from the limited number of samples available from other patients. When and where did the virus emerge to infect humans and how many geographical clusters were there, and did they arise from one or several independent chains of transmission?
The researchers found two clusters - Qatar and the United Arab Emirates in the eastern part of the Arabian Peninsula, and Saudi Arabia and Jordan in the western part, meaning that the existing cases can be traced back to one of these clusters. The last common ancestor was halfway through 2011 - about a year before the first reported cases. It is possible the disease was slowly spreading undetected during that time.
In an accompanying commentary to this Lancet study, French MERS researchers Dr Benoit Guery and Dr Sylvie van der Werf wrote, "Now is the time to design and assess therapeutic protocols [...]. The research community should learn from SARS and use these data to keep one step ahead of the outbreak."
So far, infectious disease experts recommend similar treatment and preventive protocols for MERS patients as for SARS. For updated information in Germany, consult the Robert-Koch-Institute: http://www.rki.de/DE/Content/InfAZ/C/Corona/Risikoeinschaetzung.html.
To prevent becoming infected during travel or when caring for a sick family member, the ECDC recommends avoiding close contact with an infected person, washing hands frequently if one must, and avoiding unsafe water, undercooked meats, raw fruits and vegetables unless they have been pealed. This will be important, they predict, when millions of pilgrims travel to the Middle East for Ramadan and Haji this summer and fall.