Scientists have voiced concern about this year’s Hajj pilgrimage to Saudi Arabia as they struggle with the enigmatic, deadly virus known as the Middle East Respiratory Syndrome (MERS) which is striking hardest in the kingdom.

Little is known about the new pathogen, beyond the fact that it can be lethal by causing respiratory problems, pneumonia and kidney failure.

It can also be transmitted between humans.

Even so, for any respiratory virus, the mass gathering of the Hajj provides a perfect opportunity to first spread at the two holy Muslim shrines in the cities of Mecca and Medina, and then travel around the globe at jet speed as pilgrims return home.

The 2012 Hajj drew 3.1 million people – and this year’s event likewise occurs in October, as the northern hemisphere slides into the season for coughs and sneezes.

Saudi health officials have reportedly said recently that more than 30 people out of over 50, who caught the disease, have died.

While the Hajj does not take place this year until October, many Muslim pilgrims from around the world are expected to head for Mecca this month during the fast of Ramadan.

Researchers say MERS is even deadlier than SARS which killed many around the world several years ago.

The disease can cause coughing, fever and pneumonia and has spread from the Persian Gulf state to France, Germany, Italy and Britain.