Visitors to an open house in Squirrel Hill last weekend were greeted by the homeowner, but not with a handshake.

"We're doing elbow bumps," Janet Anti told her guests, offering the outside of her bent arm. "Because of the national emergency," she added, and everyone nodded knowingly.

Such precautions against the H1N1 flu are becoming more common as people change their behavior to minimize the risk of catching or spreading the virus.

Earlier this week, President Barack Obama declared the epidemic a national emergency. H1N1, also known as swine flu, is a respiratory infection with fever, headache, aches and cough that can make those affected susceptible to pneumonia and other bacterial infections.

The incidence in Allegheny County has been rising. A survey two weeks ago of eight local hospitals showed more than 10 percent of all emergency patients complained of flu-like illness. Last week, the percentage topped 13.

Clare Collins, spokeswoman for the University of Pittsburgh Medical Center, said anyone who comes into the system's emergency rooms with respiratory symptoms is handed a face mask and urged to wear it.

Many folks have adopted other defensive measures -- sneezing into the crook of their arms, making sure to use sanitizer dispensers at the entrance of offices and hospitals, rubbing the handles of shopping carts with store-provided wipes, maybe even hesitating a moment over the free samples at bakeries and grocery stores.

An informal poll has found people wearing gloves at their health clubs, on the bus and other public places, pulling their sleeves down over their hands when they open doors, using paper towels to turn faucets on and off in rest rooms and pushing doors open with their backs.

The Mt. Lebanon Hockey Association did away with its set of shared water bottles for each team level. Two weeks ago, the group issued individual bottles with each player's name, and with squeeze lids so they don't have to put their mouths on the surface.

"We had talked about doing this before, but the H1N1 really made it happen," said Betti Smee, president of the association.

At least one professor at the University of Pittsburgh has asked students to e-mail their assignments rather than turn them in on paper to avoid transmitting the virus.

College students have formed teams to help friends and roommates who come down with the flu by bringing them food.

"The residence halls have a Help Corps so that if someone's ill, they don't have to go to the dining commons," said Rita Abent, spokeswoman for Slippery Rock University. She said the school has had 100 confirmed cases of H1N1 this year. The school recommends those who live nearby go home to recuperate, but she said many have chosen to stay in their rooms.

The virus hasn't meant the end of "Ring Around the Rosie" and other hand-holding games at child-care centers, but it has reinforced the already stringent rules promulgated by the state.

"We just do a lot of hand-washing, but no more than we already did," said Natalie Kaplan, director of Carriage House Children's Center in Squirrel Hill.

"Kids have to wash their hands before walking into the room, before coming inside after playing, before they eat. When caregivers change a diaper, they wash the child's hands, too."

Susie Flannery, catering manager of The Fluted Mushroom on the South Side, said she's noticed more invited guests missing out on big functions due to the illness.

"Everywhere we go, people are changing their counts by five or six guests for weddings and other events, mostly out-of-towners who have the flu," she said. "Nobody wants to spread it to others."

As for the elbow bump, it hasn't caught on widely, but some houses of worship are encouraging congregants to find other ways of greeting each other.

Rabbi Mark Mahler, of Temple Emanuel of the South Hills, spoke to the congregation during the High Holidays in September about foregoing the usual custom of shaking hands and hugging.

"There was an online discussion among Reform rabbis about being mindful of H1N1 and avoiding contact," he said. "The congregants wished one another a good year and chuckled because they felt constrained, but everyone understood it was the right thing to do."

Flu or no flu, some Catholic parishioners are still drinking wine from the Communion chalice and accepting the host from the hands of other people.

The Pittsburgh Catholic recently printed a front-page letter from Bishop David A. Zubik to his fellow priests, reminding them to follow hygienic practices. But, he added, "The decision whether or not to receive the Body and Blood ... remains with the individual communicant. ... Those uncomfortable receiving from the cup during the flu season should not feel obligated to do so."

Furthermore, he wrote, the Sign of Peace can be a bow rather than an embrace at any time of year.

Looking for more from the Post-Gazette? Join PG+, our members-only web site. You'll get exclusive sports content, opinion, financial information, discounts from retailers and restaurants, and more. Our introduction to PG+ gives you all the details.