MERS cases, deaths climb; study examines viral loads

Saudi Arabia reported three more MERS-CoV (Middle East Respiratory syndrome coronavirus) cases and four more deaths yesterday, raising the global tally to 64 cases and 38 deaths.

In addition, a Jordanian official said today that antibody tests showed that the first known MERS-CoV case cluster, which occurred in a Jordanian hospital in April 2012, involved 10 cases, 8 more than previously confirmed, according to a Canadian Press (CP) report.

Meanwhile, a report in Lancet Infectious Diseases today described the MERS viral load in a patient who was treated in Germany, yielding data that may help explain why the virus seems to spread less readily than did its cousin, the SARS (severe acute respiratory syndrome) virus.

New Saudi cases

The Saudi Ministry of Health (MOH) announced the three new cases and four deaths yesterday, and the World Health Organization (WHO) noted them in a statement today. The deaths came in previously reported cases.

The MOH and WHO said one of the new cases involved a 42-year-old male Saudi citizen in the Eastern region who has chronic asthma and is hospitalized. A second case-patient is a 63-year-old Saudi woman who is from the Riyadh region, has chronic diseases, and is in an intensive care unit (ICU).

Also in an ICU is the third patient, a 2-year-old who is from Jeddah and has chronic pulmonary disease, the MOH and WHO said.

The four patients who died include two from Taif, which is near Mecca, and two from the Eastern region, the MOH announced. The agency had announced two cases in Taif on Jun 14, in a 65-year-old man and a 68-year-old woman, saying both were in intensive care. The MOH has not said whether the two Taif cases were linked or separate.

In another development, Saudi authorities have urged domestic and foreign Muslim pilgrims to postpone their Hajj and Umrah visits to Mecca this year, according to media reports. The authorities cited ongoing expansion at Mecca's Grand Mosque as the reason for the advisory, but it seems likely to prompt speculation that MERS may be a factor.

In announcements on the Holy Qur'an television channel, based in Mecca, authorities advised pilgrims to postpone their plans in the interest of reducing congestion at the Grand Mosque, according to an report today.

An official with the Hajj and Umrah Committee of the Mecca Chamber of Commerce and Industry said the area where pilgrims congregate can now accommodate only 39,000 people per hour, but that will increase to 130,000 per hour after the expansion is completed, the story said. He advised pilgrims to postpone their visits for a year or two.

Eight more in Jordan outbreak

Concerning the Jordan case cluster, Dr. Mohammad Al-Abdallat of Jordan's Ministry of Health said tests of blood samples from 124 people revealed that eight had antibodies to MERS-CoV, according to the CP report. Previously only two cases, both of them fatal, in the cluster had been confirmed.

The Jordanian outbreak was a mystery when it occurred in April of last year. But samples from the patients were stored, and after MERS-CoV was described in September, tests led to confirmation of the two fatal cases.

In an initial report on the illnesses, the European Centre for Disease Prevention and Control had said they occurred in a hospital ICU and involved 11 people, including 8 healthcare workers.

In a report last December, the WHO said the cases in the Jordanian healthcare workers were probably caused by the novel virus. The cases suggested that MERS-CoV illnesses are not always severe, the agency said

Al-Abdallat said the eight newly confirmed cases involved 6 people who were sick at the time of the outbreak, 1 healthcare worker, and 1 household contact of a confirmed case, according to the CP story.

The antibody study was a joint effort of the Jordanian health ministry and US Centers for Disease Control and Prevention, the story said.

The story noted that if the WHO adds the 8 cases to its MERS-CoV count, the tally will increase to 72, with the death toll staying at 38.

Analysis of viral loads

The Lancet Infectious Diseases report describes the case of a 73-year-old man from the United Arab Emirates who was treated in Munich in March. The researchers, led by Christian Drosten, MD, found the virus in the man's stool and urine, but at low levels that don't suggest a high infection risk from those sources.

The man, who had been diagnosed as having multiple myeloma in 2008, fell ill with a fever and cough on Mar 8, the report says. Relatives said he owned camels and had taken care of a sick one shortly before his symptoms appeared, but the authors were unable to obtain any animal samples or other details about possible exposures.

The man was transferred to Klinikum Schwabing in Munich on Mar 19, the 11th day of his illness. On day 14 he had renal failure and required dialysis, and 4 days later he died of septic shock.

Fourteen healthcare workers who had contact with the patient reported mild respiratory symptoms during or shortly after his treatment, but none tested positive for MERS-CoV.

In studying the patient's viral loads, the authors found that levels of viral RNA were highest in samples from his lower respiratory tract, a finding also reported in other MERS-CoV case reports. Viral material was found in urine on days 12 and 13 of his illness, but not on day 14, after renal failure.

In addition, viral RNA was found in stool samples taken on days 12 and 16, and one of two oronasal samples taken on day 16 contained evidence of the virus, but at low levels. The virus was not found in his blood. Also, the investigators were unable to isolate the virus.

"Our data for stool, urine, and blood samples suggest a fairly low infection risk during non-respiratory care procedures," the authors write. But they caution that the patient had an underlying disease that could affect virus shedding and that their virologic monitoring began late in the patient's disease course. Data from many patients will be needed to better define shedding patterns, they comment.

They also observe that SARS patients often had high viral loads and prolonged shedding of virus in stools, which led to the routine use of stool samples for diagnostic tests. In contrast, the viral load in their patient's stool was close to the lowest detectable level. SARS spread quickly to dozens of countries in early 2003, resulting in more than 8,000 cases and about 800 deaths.

"Stool samples from many patients, including those with early stages of disease, should be tested to assess whether faecal sources could have a role in transmission, or whether MERS-CoV differs from SARS in this respect," the authors write.

In other efforts, the authors sequenced the virus's genome and ran a phylogenetic analysis based on it and four other available MERS-CoV genomes. From this, they concluded that the common ancestor of the five isolates dates to mid-2011, about a year before the first known cases occurred in Jordan.

In an accompanying editorial, two French experts, Benoit Guery, PhD, and Sylvie van der Werf, PhD, say this finding suggests that the virus could have spread unnoticed during that interval.

See also:

Jun 16 Saudi MOH statement

Jun 17 WHO statement

Jun 15 WHO statement

Jun 17 story on Saudi Hajj advisory

Jun 17 CP story

Jun 17 Lancet Infectious Diseases abstract

Jun 17 Lancet Infectious Diseases editorial excerpt

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