Saudi Arabia's health ministry today and yesterday announced eight new Middle East respiratory syndrome (MERS) cases, all of which involved contact with previously confirmed cases, including four possible healthcare exposures.
The patients are all younger or middle-aged adults from Riyadh and Medina, and most have mild infections or are asymptomatic, the Saudi Ministry of Health (MOH) said. The new detections lift the unofficial global total to 130 cases, of which 57 have been fatal.
Three of the four cases reported yesterday were asymptomatic: a 22-year-old man from Medina, a 24-year-old man who works in a health setting in Medina, and a 60-year-old man from Riyadh. The other patient is a 47-year-old man from Riyadh who is in stable condition, according to the MOH.
Of the four MERS cases reported today, all were reported from Riyadh, and three involve healthcare workers: a 47-year-old woman who had mild symptoms, a 39-year-old woman who had mild symptoms, and a 38-year-old man whose health status is stable, the MOH said. The fourth patient is a 51-year-old woman who is also in stable condition.
The newly announced cases follow closely on the heels of eight other cases that the health ministry announced on Sep 7 and Sep 8. Three of those infections were fatal.
The World Health Organization, which has not issued a MERS update since Sep 7, lists 114 global cases, 54 of which were fatal. That total does not include the 16 most recent Saudi cases.
Marc Sprenger, MD, PhD, director of the European Centre for Disease Prevention and Control (ECDC) told CIDRAP News that his agency continues to collect and analyze data about new cases and research findings to update its risk assessments. So far the ECDC views the pandemic potential as low and well below the epidemic threshold. He noted that one of the biggest questions is how humans are become infected with MERS.
Transmission patterns in Saudi Arabia, with many sporadic cases distributed over a large geographic area, point to infrequent introductions of the virus from a continuous nonhuman source, Sprenger said. "But unrecognized circulation among humans cannot be ruled out."
Zeroing in on the source of virus transmission is key to formulating guidance on how to reduce the risk of exposure and further spread of MERS, Sprenger said.
Yesterday the ECDC weighed in on a study published last week that found more evidence that camels in the Middle East have been exposed to MERS coronavirus (MERS-CoV) or a close relative. In two sets of tests, dromedary camels in Egypt had high antibody titers to MERS-CoV, but tests of humans, water buffaloes, cows, and other domestic animals in Egypt and Hong Kong found no such antibodies.
In a statement the ECDC said the new findings are in line with earlier findings of high titers in dromedary camels from Oman. The new data lead to the assumption that the animals can be infected with a MERS-CoV–like virus that is probably circulating at high levels among camels in Northern Africa and the Arabian Peninsula.
"The serological evidence is clear, but we have yet to see any direct detection or genetic characterization of the responsible virus in the dromedaries," the ECDC said.
The study's human serology findings, based on samples used in a community-based flu study in Egypt, didn't include any information on risk factors, such as close contact with or handling dromedaries, the ECDC noted. It added that more research is needed to determine if camels are the source of MERS-CoV in humans or are incidentally infected.
Sep 10 Saudi MOH statement
Sep 11 Saudi MOH statement
Sep 9 CIDRAP News story "Officials report 8 new Saudi MERS cases, 3 fatal"
Sep 10 ECDC statement
Sep 5 CIDRAP News story "Study reveals more signs of MERS-CoV in camels"