The Haj pilgrimage to Mecca, which begins next week, is a gathering of extraordinary scale. Each year three million people take part, completing one of the five pillars of Islam.
The event is a powerful personal affirmation of faith. But with so many people in such proximity to one another, it can also be a breeding ground for illness.
It has long been the case that many pilgrims return to their home countries with minor respiratory ailments, the “Haj cough”.
And while such diseases clear up without major consequences, this year’s pilgrims, about 1.75 million of whom are likely to come from outside Saudi Arabia, may be at risk of contracting something more serious – Mers coronavirus.
The virus was identified last year, and named Middle East Respiratory Syndrome coronavirus, after the region where most cases have originated. While it is highly likely the virus transferred to humans from animals, it is still unclear exactly which creatures it came from.
What is clear, though, is that it is deadly. Of the 136 people confirmed to have been infected, 58 of them, or 42.6 per cent, have died.
Understandably, doctors are worried. In the space of just a few days, the pilgrims return from Mecca to their homes across the planet.
The World Health Organisation (WHO) has already set up an emergency committee to monitor and control the spread of the virus.
In an attempt to work out which countries were most at risk, a team led by Dr Kamran Khan, a specialist in infectious diseases at St Michael’s Hospital in Toronto, looked at airlines’ data about where travellers leaving Saudi Arabia and other countries where Mers has been identified – the UAE, Qatar and Jordan – were going.
The study, published in the Public Library of Science Currents, a collection of journals, found the biggest destinations were India (which received about 16 per cent of passengers in previous years), Egypt (10 per cent), Pakistan (8 per cent), Britain (4 per cent), Kuwait (4 per cent) and Bangladesh (3 per cent).
That list makes wealth an issue – about two-thirds of the total number of Haj pilgrims are from countries towards the poor end of the scale, where health authorities are likely to be less funded. In those circumstances, what are the chances of them being able to marshal the resources to detect and deal with any outbreak?
Not good, according to Keiji Fukuda, the WHO’s assistant director general for health, security and environment. He said that while Saudi Arabia itself had made efforts to limit the spread of disease among pilgrims, “levels of surveillance remain suboptimal” in many pilgrims’ countries of origin.