In an update on seven recent MERS-CoV cases in Saudi Arabia, the World Health Organization (WHO) said yesterday that four of the patients drank camel's milk and had frequent contact with camels.
Meanwhile, the Saudi Ministry of Health's (MOH's) MERS page shows the country's case count has increased by 2, to 765, but the ministry has not provided any information on the latest cases.
All patients were older men
The WHO update provides information on seven cases, with one death, reported by the MOH between Sep 29 and Oct 11. All the patients were men at least 50 years old, and five were in their 60s or 70s.
Four of the patients had preexisting illnesses, often drank camel milk, and had frequent contact with camels, according to the WHO. Camels are known to harbor MERS-CoV (Middle East respiratory syndrome coronavirus) and are seen as a likely source of human cases, but exactly how they pass the virus to humans has not been determined.
One of the men who had camel exposure, a 51-year-old from the city of Haradh, died Oct 5, WHO said.
The agency signaled that two other patients had possible exposure to camels; exposures in one case were still under investigation, and the other involved a man in Najran who reported no contact with camels but lives in an area with many camel farms.
None of the patients were reported to be healthcare workers. Information in the WHO statement generally matches up with recent reports by the MOH, but the locations differ in two cases.
The WHO update also notes 19 cases, with 11 deaths, that were reported retrospectively by the Saudi MOH in mid-September as a result of a review of records. All but one of the cases occurred this year. The Saudi review also detected one false-positive case and a case that was counted twice.
"The retrospective identification of these 19 cases does not alter the pattern and dynamic of the epidemic and the global risk assessment remains unchanged," the WHO said.
With the latest additions and changes, the WHO's MERS global count is 877 confirmed cases with 317 deaths.
Meanwhile, Saudi Arabia's tally of MERS cases has increased to 765, from 763 on Oct 14, but contrary to its usual practice, the MOH has not posted any information about the two additional cases. The listed death toll remains at 324.
Spring outbreak isolates analyzed
In other developments, a new analysis of MERS-CoV isolates from cases across Saudi Arabia this past spring found small genetic differences between isolates from Jeddah and those from other locations, but the isolates were biologically the same, according to a report in Clinical Infectious Diseases.
The researchers, from Saudi Arabia and several other countries, report that 49% of 168 positive samples from Jeddah came from King Fahd Hospital. All the Jeddah isolates were closely related, while isolates from Riyadh were more diverse.
Viruses from the two locations did not differ from the original 2012 MERS-CoV isolate in biological characteristics such as replication and serum neutralization. "These results suggest the outbreaks to have been caused by biologically unchanged viruses in connection with nosocomial transmission," the report says.
The authors also say they discovered a hospital transmission cluster in Riyadh that included cases in Indiana and the Netherlands. The first known MERS-CoV case in the United States was identified in May 2014 in an American who worked in a Riyadh hospital and was ill during a trip to Indiana to visit relatives.
Oct 16 WHO update
Saudi MOH MERS page with case count
Related Sep 19 CIDRAP News item
Oct 16 Clin Infect Dis abstract