#14,076
We are now just over two weeks into the Holy Month of Ramadan, which sees as many as a million religious pilgrims visiting Saudi Arabia, and their MOH has reported two new MERS cases.
The first, on the 17th - a 59 y.o. male with no known camel contact - closes out epi week #20 with 2 cases, and becomes the 4th primary case reported from Riyadh in the month of May.
Today's case (epi week #21) involves a 22 y.o. female from Al Kharj City, again a primary case with no known camel contact.
While contact with infected camels is a known conduit for reintroducing the MERS virus into the human population, for many primary cases (those outside of healthcare facilities and with no known contact with a MERS case), the source of their infection remains unknown.
Although the number of community MERS cases remains limited, they represent a serious gap in our understanding of how the virus is circulating among humans, and suggest that many (presumably mild) cases are being missed by surveillance.Over the years, we've seen a number of analyses that have concluded that only a fraction of MERS cases are likely diagnosed, including:
- In November of 2013, we looked at a study published in The Lancet Infectious Diseases, that estimated for every case identified, there are likely 5 to 10 that go undetected.
- In 2015, when Saudi Arabia had recorded fewer than 1200 MERS cases, a seroprevalence study (see Presence of Middle East respiratory syndrome coronavirus antibodies in Saudi Arabia: a nationwide, cross-sectional, serological study by Drosten & Memish et al.,) suggested nearly 45,000 might have been infected.
- And a 2016 study (see EID Journal: Estimation of Severe MERS Cases in the Middle East, 2012–2016) suggested that as much as 60% of severe Saudi MERS cases go undiagnosed.
