MINA, Saudi Arabia — Millions of Muslim pilgrims, many wearing surgical masks, jostled shoulder-to-shoulder furiously casting pebbles at stone walls representing the devil Saturday — the hajj ritual of highest concern to world health authorities watching for an outbreak of swine flu.
The annual Islamic pilgrimage draws 3 million visitors each year, making it the largest yearly gathering of people in the world and an ideal incubator for the H1N1 flu virus.
So far, only about 60 flu cases have been uncovered, but health officials warn it is likely spreading silently among pilgrims — and the true extent of the push that hajj has given to the virus won't be known until later, after the faithful have returned to their home countries around the world.
Saudi officials, along with American and international health experts, have geared up here to try to limit any outbreak. But they also are using the pilgrimage as a test case to build a database, watch for mutations and look for lessons on controlling the flu at other large gatherings like the 2010 soccer World Cup in South Africa.
The stoning-of-the-devil ritual, performed on Friday, Saturday and today, is when the crowds of pilgrims at the five-day hajj are at their height and contact between them is closest.
Under a hot sun Saturday, hundreds of thousands of sweaty bodies pressed against each other toward the stoning walls. The majority did not wear masks, and many sneezed, coughed and spat, and looked exhausted.
Other parts of the hajj — such as the circling of the Kaaba shrine in Mecca — see a lot of physical contact and close quarters, but perhaps not as much as the rites at Mina, in a desert valley outside Mecca. The epic crowds squeeze together along ramps and platforms that control traffic around the walls. They push past each other to hurl their pebbles at each wall, often shouting curses at Satan and rejecting his temptations.
"This is when the crowding is at its peak and this is where the spreading is likely to take place," said Hassan el-Bushra, an epidemiologist at the Cairo office of the World Health Organization. "All the hajjis (pilgrims) are in a very limited physical location."
American and Saudi health officials circulated among the sprawling tent camp at Mina where the pilgrims live and gave the faithful cheek swabs for testing later.