Saudi Arabia and the United Arab Emirates (UAE) reported a total of 21 more MERS-CoV (Middle East respiratory syndrome coronavirus) cases today, while the European Centre for Disease Prevention and Control (ECDC) predicted that more exported cases are likely to crop up in Europe.
In addition, in the first word of any genetic sequencing results for recent MERS-CoV isolates, a news report in Science said that preliminary findings from analysis of one viral protein yielded no evidence of mutations. The recent spurt of cases in the Middle East has triggered much speculation about changes in the virus, among other possible causes.
The Saudi Arabian Ministry of Health (MOH) reported 14 new MERS cases today, with 4 deaths. Seven cases are in Jeddah, site of a healthcare-related outbreak, while four are in Riyadh and three are in Mecca, according to a computer translation of the statement, posted on Avian Flu Diary, an infectious disease blog.
Four of the new case-patients are asymptomatic, four are in stable condition, and two are in intensive care units, the MOH said. Among the patients are four healthcare workers, all nurses, three from the Philippines and one from India.
The four patients who died were all men: an 81-year-old Palestinian, a 64-year-old Palestinian, a 30-year-old Saudi, and a 40-year-old Bangladeshi.
The MOH also announced the death of a previously reported case-patient, a 59-year-old man in Riyadh. With today's report, the MOH raised its MERS count to 313 cases with 92 deaths.
In the UAE, a report of seven new cases in Abu Dhabi today came from the Emirates News Agency, also known as WAM.
The Health Authority Abu Dhabi said the seven patients have mild or no symptoms and are isolated in a hospital, according to the brief story. It gave no other details about the cases.
The story also said eight other case-patients have now tested negative for the virus and will soon be released from a hospital where they have been kept in isolation. The story gave no total number for the current outbreak in the UAE, but it said 18 case-patients have now tested negative for the virus.
ECDC sizes up risk once again
The ECDC, in an updated risk assessment today, said it expects to see more MERS cases in Europe, but it still holds to its earlier finding that the risk for Europeans visiting or living in the Middle East is low and that secondary transmission from imported cases is low. The agency also weighed possible explanations for the recent spate of cases and concluded that there's not enough evidence to settle on any of them.
The updated assessment comes in the wake of the first case in Greece, reported a week ago in a Greek man who lives in Jeddah but was diagnosed in Athens. Cases have previously been reported in France, Germany, Italy, and the United Kingdom, all with links to the Middle East.
"Given the current epidemiology on the Arabian Peninsula, it is likely that more cases will be imported and detected in [European Union] Member States," the ECDC said. "Further vigilance in assessing patients with travel history to the affected region is warranted."
The report says there is too little solid information to draw any firm conclusions on the risk posed by the latest outbreaks. "It is not clear what role nosocomial transmission is playing in these clusters or whether wider community transmission is taking place," it adds. "However, unless these recent detections are due to laboratory contaminations, the epidemiological evidence from Saudi Arabia and UAE seems to suggest increased circulation of the virus or increased case detection among humans."
The recent increase in exported cases, which have turned up in the Philippines and Malaysia as well as Greece, "might indicate increased transmissibility of the virus and perhaps longer transmission chains than have been seen in the past," the report states. "An apparent increase in the size of nosocomial clusters also supports this hypothesis."
In examining possible explanations for the higher flow of cases, the ECDC said there is too little information on MERS-CoV testing practices in Saudi Arabia to determine if a change in such practices might help explain the situation. "However, the fact that the proportion of asymptomatic to symptomatic confirmed cases has remained stable during the increase in cases in April indicates that increased testing alone is unlikely to explain the increase, as increased testing of contacts is expected to increase the proportion of asymptomatic cases."
Similarly, the agency said there's not enough information to determine if increased transmission of MERS-CoV from camels to humans is a factor in the situation. It said that the number of camel farms near cities has risen in the past 10 years, but a better understanding of MERS-CoV epidemiology in camels is needed to fully assess the risk.
As for the possibility of infection control lapses, the report says a full evaluation of the preventive measures used at the involved healthcare facilities could shed light on the issue. Likewise, increases in close-contact infections, nosocomial transmission, and asymptomatic infections suggest the possibility of more effective transmission of the virus, but lack of data forbids any conclusions as yet.
The report says laboratory contamination of samples is unlikely to be the "only explanation" for the increase in cases, since the recent outbreaks have occurred in three cities in two countries.
The agency also cited a need for genetic analysis of recent MERS-CoV isolates, stating, "Gene sequences from the recent human cases have not been submitted to GENBANK or other publicly available databases," making it impossible to determine if the virus has changed.
As for genomic analysis, a news report yesterday in Science said virologist Christian Drosten, MD, of the University of Bonn received samples from 31 MERS-CoV patients in Jeddah last week. Drosten told the journal he found the virus in all but one of the samples.
Drosten said partial sequencing of the spike protein gene of all 30 isolates showed that they are identical to each other and also to older isolates, revealing no mutations in that part of the genome, according to the article. He also said he was proceeding with sequencing the rest of the genome.
In a related development, a Eurosurveillance report published yesterday on Greece's first MERS case said sequencing of the virus from that case was under way. The case involved a 69-year-old Greek man who lives in Jeddah and was sick when he flew to Greece on Apr 17. He has been in critical condition and on a ventilator since Apr 20, the report said.
Health officials identified and contacted 73 contacts of the patient, none of whom have gotten sick, according to the report. Among them were two healthcare workers who had face-to-face contact with him for more than 15 minutes.
Machine-translated Apr 25 Saudi statement on new cases, via Avian Flu Diary
Apr 5 Emirates News Agency report on UAE cases
Apr 25 ECDC risk assessment
Apr 24 Science news story
Apr 24 Eurosurveillance report on case in Greece