May 17, 2013 (CIDRAP News) – The World Health Organization (WHO) voiced increased concern today about the possibility of community transmission of the novel coronavirus, while sketching in a few more details about a hospital-centered case cluster in Saudi Arabia and the clinical spectrum of the infection.

Although sustained transmission in the community has not been seen, the WHO said, "The continued appearance of cases that are not part of larger clusters, and who do not have a history of animal contact, increases concerns about possible community transmission. This possibility is being investigated by authorities in Saudi Arabia."

The WHO has confirmed 40 cases and 20 deaths from novel coronavirus infections since the pathogen was identified in 2012, most of them in older men.

The virus has gone by various names to date, but a committee of experts recommended this week that it be called Middle East respiratory syndrome coronavirus, or MERS-CoV. (CIDRAP News will use the new name henceforward.)

Today's WHO summary and literature update follows the emergence in the past 2 weeks of the hospital cluster in Saudi Arabia and the first two MERS-CoV cases in France.

The hospital cluster has been reported to include 21 cases, with 9 deaths; news reports have linked it to the Al-Moosa General Hospital in Hofuf, Eastern province. On May 15 the WHO reported that two healthcare workers who caught the virus from patients were part of the cluster.

Today's report adds some new information about the cluster but also raises more questions. It says the cluster includes 16 males and 5 females, with a median age of 56 years. Six patients remain critically ill, implying that another six have less severe illness or have recovered.

Most of the cases were linked to one healthcare facility in Al-Ahsa, but, as reported previously, some of those who became infected were not patients at the facility, the report notes.

It adds, "Three family members of cases linked to the facility and two health care workers not associated with the Al-Ahsa facility but who had contact with laboratory confirmed cases have become infected."

The report doesn't specify where the two healthcare workers were exposed to infected patients. WHO spokesman Gregory Hartl told CIDRAP News today that the agency doesn't know where the exposures occurred.

The report goes on to say, "Two additional cases have been identified in the community that did not have any links with other cases from the Al-Ahsa healthcare facility. Although investigations are still ongoing into the source of this outbreak, early information indicated that only a small minority of these cases had contact with animals in the time leading up to their illness."

The WHO reiterated previous statements that MERS-CoV is believed to be of animal origin and to be sporadically spread to humans by an unknown route. Human transmission so far has been confined to healthcare facilities and close contacts of patients, the report noted.

It adds, "The recent increase in cases may in part be related to increased awareness among the medical community, however the demonstrated ability of this virus to transmit between humans and to cause large outbreaks, has increased concerns about the possibility of sustained transmission."

On the clinical manifestations of MERS CoV infection, the statement revealed that many patients have had gastrointestinal symptoms, including diarrhea. "One patient, who was immunocompromised, presented with fever, diarrhea and abdominal pain, but had no respiratory symptoms initially; pneumonia was identified incidentally on a radiograph," it states.

That description apparently refers to the first French case-patient. In reporting that case on May 8, the WHO said the patient was immunocompromised and did not have respiratory symptoms when he first got sick on Apr 23. Other reports said the patient, a 65-year-old man, fell ill after returning from a 9-day vacation in Dubai, United Arab Emirates.

Other clinical findings in MERS-CoV cases include acute respiratory distress syndrome, renal failure requiring hemodialysis, consumptive coagulopathy, and pericarditis, the WHO said.

In other comments, the WHO said that the large number of patients with preexisting medical conditions "suggests that increased susceptibility from underlying medical conditions may play a role in transmission."

The agency also said the healthcare workers' cases and other instances of nosocomial transmission point up the need for careful use of infection control measures.

Like the WHO statement, an updated MERS-CoV risk assessment released today by the European Centre for Disease Prevention and Control (ECDC) observed that infected persons may not have respiratory symptoms at first.

"The first French case raises the possibility that presentations may not include respiratory symptoms initially, especially in those with immunosuppression or underlying chronic conditions," the assessment says. "This needs also to be taken into account when revising case-finding strategies."

The ECDC also said that mapping routes of medical evacuation or emergency care from the Arabian Peninsula and countries neighboring the European Union should be considered to determine the most vulnerable EU centers where cases might arrive.

Regarding the MERS-CoV situation in the Middle East, the agency said, "It is unusual to have such a degree of uncertainty at this stage in an outbreak."

See also:

May 17 WHO summary and literature update

May 17 ECDC risk assessment