This week was posted the first case control study on MERS in KSA. Not really a surprise but new evidence on the key role of dromedary camels as the source and reservoir for MERS-CoV . Two main causes to explain the spread of MERS in KSA since 2012:
- Zoonosis: People indirect contact with camels are more exposed to get MERS; Camel herdsmen or slaughterhouse workers are mostly the primary cases.
- Nosocomial outbreak: People with underlying or pre-existing medical conditions like diabetes,cardiac or pulmonary failures,kidney disease or immuno-compromised are high risks to get MERS at the hospital whenever a lack of the infectious control protocol is occurring. Health Care Workers (HCW) are impacted but also responsible for this nosocomial outbreak.
Regarding Epidemiology, this study brings up interesting data regarding the ratio primary/secondary MERS cases:
- 6% are primary cases related to zoonosis; up to 56% died. This fatality rate is over the total MERS fatality rate around 42%.
- 94% are secondary cases, human to human spread which occurs mostly at the hospital (Emergency room,ICU,renal dialysis) due to underlying poor medical conditions.
The flow chart above summarizes the different root causes, risk exposure and how risks factors are playing a key role in the outcome.