For the second time in the past three days (see Sunday’s Saudi MOH Reports A New Primary MERS Case In Hofuf), the Saudi MOH is reporting a new primary MERS case from Hofuf (aka `Hufoof’). Hofuf was the scene of a prolonged nosocomial outbreak earlier this year (April-July), involving more than 40 patients.
The designation as a `Primary’ case only tells us these cases had no known exposure to an indentified MERS case. Nearly 40% of all known Saudi cases fall into this `primary’ category.
Some percentage of these cases likely had contact with camels - or camel products – but for most their source of exposure is unknown. While often mentioned as a possibility, the role of mild or asymptomatic cases in facilitating the community spread of MERS remains largely unproven.
Our understanding of community transmission of the MERS virus continues to be hampered by the lack of a well-mounted case-control study out of Saudi Arabia (see WHO EMRO: Scientific Meeting Reviews MERS Progress & Knowledge Gaps).