“We don’t issue hajj permits to those who have performed hajj during the past five years,” said Anazi. (Arab News)

Authorities say they have tightened health controls for this year's pilgrimage, which health experts have warned could create the conditions in which a fatal flu pandemic could emerge.

The director of the health control center at King Abdul Aziz International Airport in Jeddah, the main gateway of pilgrims, explained the screening procedures being carried out by his officers.

“The first thing we did one month ago was compile a list of countries plagued with certain diseases,” Dr. Mohammed Al-Harithy told the Saudi daily Arab News.

He said special measures had been taken to deal with pilgrims coming from Africa, the Indian Subcontinent and countries like Egypt and Yemen where infectious diseases such as cholera and meningitis are common.

“Once a plane from a plagued country lands, we dispatch two inspectors,” Harithy said.

“The door of the aircraft is not opened until our people get there.” He says inspectors collect a written certificate from the pilot confirming that the plane has been disinfected and check for empty spray canisters as proof.

Some 4,500 pilgrims from Kyrgyzstan will be vaccinated against meningitis — a disease involving the inflammation of the tissues around the brain or spinal chord, Harithy said.

The Kingdom will pay for the inoculations because of the economic difficulties in the former Soviet republic, he added. A glossy poster at the entrance to the airport clinic tells pilgrims to “pitch in to stop the spread of avian flu.”

Renovations to the Jamrat bridge, which began last year, would be completed after this year's hajj, allowing more pilgrims to come in the future, Osama Al-Bar, the head of the state-run Institute for Hajj Research, told Reuters.

Last year each of the three pillars was transformed into a wall, making it easier for pilgrims to direct their stones.

But there remains the danger of deadly crushes on the bridge where thousands of pilgrims converge toward the walls.

“The bridge will be demolished after this year's hajj and (replaced with) a new one costing 4.2 billion riyals ($1.12 billion)," Bar said, outlining a four-level system of entrances and exits to the three walls, including a subway.

There have been many deadly stampedes in the past. In 2003, 14 pilgrims, including six women, were killed during the first day of the stoning ritual, 35 in 2001 and 118 in 1998.

The worst toll was in July 1990, when 1,426 pilgrims were trampled or asphyxiated to death in a stampede in a tunnel in Mina.

Pilgrims hurl seven pebbles from behind a fence or from the overhead bridge every day for three days at each of the three 18-metre (58-foot) high concrete pillars.