Map: Geolocations of MERS Cases in Saudi Arabia in the Last 3 months, April 30, 2014

About 215 MERS cases have been reported in Saudi Arabia since February 1, 2014, from 8 geographic areas of the country.

Number of Current MERS Infections on the Arabian Peninsula May Be Declining

Since January 1, 2014, about 250 cases of MERS infection have been reported by various public health agencies and official media outlets. The number of reported cases began to increase dramatically about the 9th of April. Most of these cases (about 200) have been reported from the Kingdom of Saudi Arabia.

The graph below suggests that the number of MERS cases may have peaked about April 20, and the outbreak is now being better controlled.

 

 Notes: The date of onset for an individual case is used where available. If onset date is unavailable, the date of hospitalization or death is used. If the case is reported as asymptomatic or no other information is available, the date of report of the case is used.

Map Showing the General Locations of MERS-CoV Cases on the Arabian Peninsula (April 21, 2014)

Map of the general geolocations of more than 330 local MERS-CoV infections on the Arabian Peninsula as of April 21, 2014. Locations with 10 or more reported cases are labeled in black. The area of the circle depicts the relative number of reported cases at that location.  

Reported Geolocations with 10 or More MERS-CoV Cases
Geolocation	Case Count (as of April 21, 2014)
Riyadh	100
Jeddah	73
Abu Dhabi	29
Al Hofuf	26
Ash Sharqiah	17
Al Ain	15
Hafar Al-Batin	11
Madinah	11

Nosocomial Clusters of MERS-CoV Cases on the Arabian Peninsula

Since 2012, the Middle East respiratory syndrome coronavirus (MERS-CoV) has infected almost 300 people, many of them healthcare workers including nurses and doctors. Infections of health care workers and patients that take place within or are associated with a hospital or health care facility are referred to as nosocomial infections. A large number of MERS cases can be classified as nosocomial infections. For the purposes of this discussion, localized geographic clusters of MERS-CoV cases that appear to represent hospital-acquired infections are referred to as nosocomial MERS clusters. Under this definition, there has been at least 10 separate nosocomial clusters of MERS cases.

Of these clusters, only two have been reported in the literature [1,2]. The remaining nosocomial clusters are identified based on media reports, ministry of health reports, and World Health Organization reports. The quality of this data is uncertain but trends are clear and speculations can be advanced. 

The table below identifies these nosocomial clusters by location, month of outbreak for the cluster, the putative number of MERS cases within the cluster, and the number of infected health care workers reportedly associated with the cluster. The case counts include both confirmed and suspected/probable cases. The map below depicts the general locations of these clusters throughout the Arabian Peninsula. 

Table

Map

Discussion

Health care workers represent about 44% of the nosocomial cluster cases. In addition to the health care workers included in the clusters, another 21 health care workers are reported as sporadic or isolated MERS cases. The source of infection for these other health care workers is not identified, but it is likely that there have been additional nosocomial clusters that are not reported. 

Based on these data, it is clear that infection of healthcare workers with the MERS coronavirus is not a rare or random event. More than 2 years after initial hospital cluster in Jordan, health care workers continue to become infected while treating patients. We can assume that health care workers in the Arabian Peninsula region, are now familiar with, and aware of, the dangers of MERS. The fact that MERS is still infecting health care workers and possibly other patients within a hospital setting strongly suggests that MERS is highly infectious among individuals who have close contact with each other. The fact that about 25% of all reported MERS infections are doctors, nurses, and other health care workers is indicative of the infectious nature of this novel coronavirus. 

[1] Novel coronavirus infections in Jordan, April 2012: epidemiological findings from a retrospective investigation

[2] Hospital outbreak of Middle East respiratory syndrome corona­ virus

World Map of Countries with Confirmed or Probable MERS-CoV Cases

The map below shows the countries that have reported either confirmed/suspect or imported MERS-CoV cases as of April 18, 2014.

 

Increasing Number of MERS-CoV Cases in the Jeddah Outbreak

As of  April 15, the total number of MERS-CoV cases associated with the outbreak in Jeddah, Saudi Arabia was at least 30 individuals.  See:

Current Status of the MERS-CoV Outbreak in Jeddah, Saudi Arabia 

The count of MERS cases in the Jeddah outbreak is now at least 47 individuals, including one pilgrim from Malaysia (link) who died. A media report indicates that two other traveling companions from Malaysia are now exhibiting symptoms as well (link). Whether these two other individuals were infected from a common source in Jeddah or a result of human-to-human transmission remains to be reported.