Despite the fact that the virus has infected 36 people so far in South Korea, claiming four lives, the latest MERS-CoV outbreak is not likely to set off a global pandemic, say experts.

While there are new cases reported daily, this does not represent a new spread and can be accounted for by the 1,600 odd contacts of the Korean man who spread the virus before it was diagnosed.

The coronavirus, MERS-CoV holds potential pandemic threats but that would happen only once the virus begins to mutate. This has not been seen so far.

Such mutation can happen anytime but is not inevitable, writes Nature. The virus will be sequenced to look for any genetic changes.

It is only if new cases are reported outside the contact circle and away from hospital settings that there is need for alarm.

When the virus spreads between people, as now in South Korea, this happens only in hospital settings or patient case where medical procedures on undiagnosed patients can generate aerosols from the lungs that contaminate the area.

Otherwise, MERS-CoV which infects the deeper areas of the lung is not coughed out.

The virus, first detected in Saudi Arabia in 2012, is primarily an animal virus. It is thought to have originated in bats, and probably jumped to humans through camels.

The current outbreak was sparked when a 68-year-old Korean man flew back to Seoul on 4 May after a visit to four Middle Eastern countries.

MERS-CoV like any other respiratory ailment spreads when the virus gets into the air by sneezing or coughing, as also contact with contaminated surfaces. It can be controlled by public health measures.

Both MERS-CoV and Severe Acute Respiratory Syndrome (SARS) belong to a common class of viruses known as coronavirus (named for the crown-like spikes on their surface).

The difference is that SARS evolved the ability to spread easily among people. MERS CoV has not, so far.

First recognized in China in 2001, SARS-CoV caused a worldwide outbreak with 8,098 probable cases including 774 deaths from 2002 to 2003. Since 2004, there have not been any known cases of SARS-CoV infection, says the Centers for Disease Control and Prevention.

A MERS outbreak in Jeddah in Saudi Arabia last year resulted in 255 people becoming infected, and a cluster of infections in 2013 at a hospital in Al-Hasa, in eastern Saudi Arabia, resulted in 23 confirmed and 11 suspected cases.

The corona viruses cause mild to moderate upper-respiratory illness which turns severe with SARS.

The World Health Organization has warned that the world is highly vulnerable to a severe flu pandemic much severe than the 2009 swine flu outbreak that killed over 284,000.

Of particular concern is the highly pathogenic H5N1 avian influenza virus spreading across new regions of the globe.

The H7N9 strain of the avian virus is swapping genes with other types of flu viruses, giving rise to new strains that could spread fast in humans.