Mexico City  - The bells of Mexico City's cathedral rang in prayer, and the figure of Our Father Jesus of Health was taken out onto the streets of the city's historic centre Sunday for the first time in 150 years to ask God for protection.

As in the times of smallpox, Roman Catholics joined in prayer against the ongoing flu epidemic, including cases of swine flu, that has left 149 people dead in the country in less than a month.

They had good reason. The streets and metro system of the nation's capital turned ghostly as residents donned face masks, handed out by the Mexican army. Football games were played in empty stadiums. Schools were closed until May 6 and other public gatherings were shut down.

Additional worry came from a 5.7-scale earthquake that shook the city to its bones Monday and sent masked workers fleeing from buildings. Fortunately for the city, it was spared the added insult of physical damage from the temblor.

But times are different from the 16th century Aztecs of the ancient Tenochtitlan who had to face the smallpox brought ashore by the Spaniards. They are different from the later devastating epidemics of measles, cholera or mumps.

In fact, residents of Mexico City have many better weapons against disease - face masks, anti-viral drugs, modern communications and an efficient government that can quarantine if need be.

But time-honoured methods still carry their weight in modern Mexico. That was clear on Sunday with the procession of Our Father Jesus of Health, and with the novena - usually a nine-day-long series of prayers - to Our Lady of Guadalupe being organized by the Archdiocese of Mexico City for the coming days.

"You who have rescued us from other plagues, entrust us to the mercy of He who healed us with His wounds and freed us from death with His Resurrection," the devout are praying, at the request of Mexico's Primate Cardinal Norberto Rivera.

On Sunday, most churches in the Mexican capital had cancelled all community masses until further notice, following last minute orders from church authorities. In the coming days, there will be no communal, large-scale first communions or confirmations and no large wedding masses.

When it comes to faith, something has changed with respect to the plagues of old. Earlier, churches would fill up to pray at times of epidemics, said Archdiocese spokesman Hugo Valdemar, whereas now - in the face of scientific progress - people know that concentrating in closed spaces can be worse. Viruses pass from person to person even in God's house.

Some onlookers were incredulous late Sunday as the procession carrying Our Father Jesus of Health - a figure of Christ on the cross that had not been carried through the streets since 1850 - advanced, carried by men with blue face masks.

"That won't do any good," one person muttered.

However, Valdemar disagreed.

"It is a centenary tradition to take out Our Father Jesus of Health on people's shoulders when a pest or epidemic attacks the population," he noted.

Mexico has one of the largest numbers of Roman Catholic faithful in the world, second only to Brazil. Religion has deep roots among the population, particularly with the adoration of Our Lady of Guadalupe.

The Guadalupe basilica, which usually hosts many thousands of faithful every Sunday, is now holding masses only behind closed doors.

Cardinal Rivera invited all Catholics to pray at home, follow mass on the radio and on television and take part in the novena of prayer.

The goal is to ask the Virgin Mary "to free the city and the country from this threat that is hanging on their residents, as she prodigiously did in the past, especially in the pests that the same city suffered in the years 1554, 1695, 1736 and 1850." (dpa)