? Cartoon by Yu Dacheng [http://cartoon.chinadaily.com.cn/]

XI'AN - A battalion of more than 300 hungry elementary school students storm toward the dining hall, eager to get their hands on mantou,or steamed bread. Washing their hands prior is required by teachers, but with only eight hand-washing stations, the words are ignored by many, because evidently, appetite trumps cleanliness.

But there are some students at Zhongxun Elementary School in Dancun Town, northwest China's Shaanxi province, realizing the importance of washing hands.

Sun Kexin ,a six-grade girl, stops at a water station, squeezes some soap on the hand and start to hum the Happy Birthday song. "It takes at least 20 seconds to wash your hands thoroughly," says Sun. "So you sing the 'Happy Birthday' song twice."

Sun acquired this knowledge from a health program marking the Global Handwashing Day last autumn at school. The Global Handwashing Day, falling on October 15 every year, is a campaign started in 2008 to encourage washing ?hands with soap and make it a life-long practice to prevent the spread of viral infection.

The program Sun attended was jointly sponsored by the United Nations Children's Fund (UNICEF) and China's National Committee for the Patriotic Public Health Campaign. During the past year, though Sun could not always follow all six steps of handwashing the program promotes, she dutifully maintains two - soap and 20 seconds after use of toilet and before eating.

Dr. Yang Zhenbo, chief of the water, sanitation and hygiene program for UNICEF China said, "People all over the world wash their hands with water, but handwashing with soap isn't as common as we thought."

Figures show that less than a third of people around the world wash their hands with soap after using the toilet or before eating, said Yang.

Yang says the figure was only nine percent in research conducted in nine counties in Shaanxi supported by UNICEF and two other international agencies in 2007 after observing 600 families -- 3,500 people -- after they used the toilet.

Yang says hands often carry infectious diseases like diarrhea, flu and pneumonia from person to person.

"Water does not wash away germs -- it does with soap," Yang says.

Soap breaks down grease and dirt that carry the most germs and interrupts the routes of transmission, Yang says. It could reduce the incidence of diarrhea and pneumonia.

"If properly practiced, handwashing with soap could reduce the incidence of diarrhea among children under five by almost 50 percent and respiratory infections by nearly 25 percent," Yang says.

But changing behavior isn't easy, and it's particularly a challenge in northwest China, where water and handwashing facilities are insufficient.

Zhongxun Elementary School has more than 600 students half of whom are boarders. But it has only 11 taps for running water -- eight outside the dining room, two in the restrooms and one in the students' dormitory. Also, the running water supply isn't stable, so large water tanks sit on the school's playground.

Girls beat boys when it comes to washing their hands, said Zheng Ping, a teacher at the school.

"Girls like to keep their faces and hands clean," Zheng says. "They use soap and enjoy the pleasant scent."

But even when boys do wash their hands, they tend to rush through it, Zheng says, they don't keep the soap on their hands long enough, and it's hardly unusual to find boys with dirt beneath their finger nails.

Zheng becomes especially vigilant concerning handwashing during winter and flu seasons.

"When students return from gym class or head for lunch, I order them to wash their hands," she says.

Zheng's work as a handwashing sentry has paid off, as student sick days have decreased. In her class with 57 students, usually four to five were absent during flu season a couple of years ago, but last winter, only one or two were so.

UNICEF started to do handwashing program with government partners in China in 2008. Several months after the May 12 Wenchuan earthquake, UNICEF went to the quake-hit regions in southwest Sichuan Province, teaching people who then lived in crowded, unsanitary environment to wash hands properly to prevent spread of disease. I

In the following years, UNICEF expanded its program across the country. Last year, the program reached 1,170 schools with more than 1.2 million students.

Yang said children are vulnerable to disease, but washing hands isn't just for children but everyone.

He says many city residents believe the environment is getting cleaner, so it's unnecessary to wash hands frequently. But Yang says washing hands after defecation and before eating is absolutely necessary, and certainly does not indicate obsessive cleanliness.

Yang dismisses the notion that adults seldom touch food with their hands at meals, making it unnecessary to wash hands before eating. And Yang encourages parents to set an example for their children, who touch food with their hands all the time.

Yang said besides diarrhea and respiratory illness, soap and water combine to combat a host of other illnesses, such as parasitic worms, eye infections like trachoma, and skin infections like impetigo.

This year, the promoters of Global Handwashing Day seek to make hand washing a habit and social norm in China.

Habits are contagious, as Sun realized when she returned home and proudly told her family what she had learnt from the program.

"Now my grandma and my mom always wash their hands with soap before preparing meals," Sun says. "I told them I won't eat if they don't wash thoroughly first."