The virus, first detected in humans two years back, has caused 152 deaths

Despite a recent surge of ‘Middle East respiratory syndrome coronavirus’(MERS-CoV) cases, a meeting of an expert committee called by the World Health Organisation has concluded that conditions for declaring an ‘Public Health Emergency of International Concern’ had not been met.

The fifth meeting of WHO’s Emergency Committee for MERS-CoV, which was first convened last July, took place by teleconference on Tuesday. The Committee took into account the fact that there had been sharp increase in cases since this March, particularly in Saudi Arabia but also in the United Arabian Emirates. Moreover, a majority of these cases had occurred in hospital settings, said Keiji Fukuda, the WHO’s Assistant Director-General, during a press briefing today.

But, on the other hand, “there is no convincing evidence right now of an increase in the transmissibility of this virus,” he pointed out. Infected individuals were not passing on the virus to more people than before. Nor were there indications of MERS infections sweeping through communities, he said.

Preventive steps

The Emergency Committee, however, has called for a number of steps to be urgently taken, including better national policies for infection prevention and control in healthcare facilities.

Since the virus was first detected in humans two years back, a total of 152 people have now died and 495 have been confirmed to have contracted the virus in Saudi Arabia, according to an Associated Press report. Most cases of the disease have been in the desert kingdom.

Egypt, Greece, Malaysia, Philippines, and the U.S. have recently reported isolated cases in individuals who had travelled there from the Middle East. The Netherlands has now reported its first such case.

Seasonality could be a factor driving the recent increase. The virus is widespread in camels in the Middle East and north-east Africa, and the animals appear to become infected when young. Increased spread of the virus from camels to humans might be contributing to the outbreak.

An increase in community-acquired cases noted since March this year mimicked what happened in April last year, noted a recent editorial in the journal Eurosurveillance. “It is interesting to note that the possible seasonal increase of human MERS-CoV cases corresponds to the end of the calving season for camels in Saudi Arabia.”

In 2003, another coronavirus, which caused ‘severe acute respiratory syndrome’ (SARS), had suddenly emerged from southern China and spread rapidly across the world. The virus infected over 8,000 people and killed nearly one in ten of them before the epidemic was successfully halted.

Key lessons

There are two key lessons from SARS, according to J.S. Malik Peiris, a well-known virologist at the University of Hong Kong, whose group was the first to isolate the virus responsible for that outbreak.

One was the need for good infection control to stop transmission within hospitals and healthcare facilities, said Prof. Peiris in an email. The other was identifying the animal source of infection and using interventions to stop that transmission. “These are exactly the things that are needed with MERS.”

In the case of MERS, although camels are the likely source of the virus, how transmission from animals to humans takes place is not yet clear.

As MERS-CoV manifested in humans mostly as a respiratory disease, the prevailing thinking is that such transmission occurred via a respiratory route, remarked Ian Mackay, a virologist with the Australian Infectious Diseases Research Centre at the University of Queensland.

Small virus-bearing droplets and aerosols, which might be inhaled, could be generated in many ways. While drinking camel milk had garnered much attention of late, “it is possible that milking a camel exposes the milker and those around them, as well as the drinker of fresh frothy milk, to an aerosol which may contain MERS-CoV,” he pointed out in an email. Similarly, camel urine might generate aerosols during its collection and application.

The Emergency Committee for MERS-CoV has called for studies to better understand the epidemiology of the disease and risk factors underlying the spread of the virus.

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