Saudi authorities are working hard to ensure Muslim pilgrims flocking to join the annual pilgrimage to Makkah are disease-free and pose no threat to the oil-rich kingdom's security.
The director of the health control centre at King Abdul Aziz airport in the second city of Jeddah, the main gateway to Makkah, proudly explains 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," says doctor Mohammed al-Harthi.
He says special measures have been implemented 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.
By Friday more than 1.1 million pilgrims had already arrived in Saudi Arabia ahead of the annual pilgrimage, or hajj, an interior ministry official said.
It is estimated that a total of two million pilgrims from all corners of the earth will come to perform the rites of the hajj, one of the five pillars of Islam and a once-in-a-lifetime obligation for all devout and able Muslims. Most arrive by air in Jeddah, about 70 kilometres (45 miles) west of Makkah.
Although the hajj itself only starts next Sunday, many pilgrims are already in Makkah to perform a lesser pilgrimage known as the umrah or have headed further north to Medina to pray at the mosque where Prophet Mohammed is buried. "Once a plane from a plagued country lands, we dispatch two inspectors," says Harthi. "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.
Passengers are then bused to a special pilgrims' terminal where they are required to produce a clean bill of health from their home country and are given supplementary vaccinations where necessary.
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, Harthi said.
The Saudi authorities are paying for the innoculations 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." But Harthi says that, besides giving the clinic's 350 staff the drug Tamiflu, no other exceptional measures have been taken to combat the threat of bird flu, which killed more than 70 people in Asia last year, 11 of them in the world's most populous Islamic nation, Indonesia.
Hardjanta Imam Subandi, a 41-year-old pilgrim from Jakarta, flips open his passport to show an attached health certificate in both Arabic and English.
"Besides the required vaccines, no one in our caravan took Tamiflu. We put our faith in Allah," he says.
Many pilgrims cover their mouths and noses with masks in public spaces.
It is a matter of national pride for Saudi Arabia, which considers itself the custodian of Islam's two holiest shrines in Makkah and Medina, that the annual pilgrimage go smoothly and without the deadly incidents that have marred it in the past.
Besides trying to prevent more stampedes like those that killed 251 people in 2003 and 1,426 in 1990, security forces are also on high alert against infiltration by Islamic militants as they continue to battle a wave of unrest blamed on al Qaeda sympathisers.
Soldiers in green combat fatigues protect the perimeter of Jeddah airport while security force personnel in brown uniforms man checkpoints along the highways to Makkah and Medina.
In Makkah alone, a 10,000-strong force has been mobilised from the kingdom's security and civil defence units, the Okaz daily reported, citing its commander Major General Alwani Jeddawi.
"No to terror," says a poster depicting a bloodied hand hung in the lobby of one of Makkah's hotels.
Pilgrims are invited to attend a lecture on the "evils of terror" and take part in a raffle benefiting those killed in "the line of duty".
Five policemen and two suspects on the kingdom's list of 36 most-wanted militants were killed in clashes north of Riyadh over the past week.