Marla Davis Bellamy sees violence the way a doctor sees the flu: an infection that can be prevented.

She leads Philadelphia CeaseFire, part of a growing international movement tackling violence as a public health crisis.

So it makes sense that CeaseFire is teaming up with the city's trauma centers. The aim: along with offering medical care for victims of violence at hospitals, try to prevent them from striking back and escalating the cycle of violence.

"A gunshot victim one day is a perpetrator the next," said Davis Bellamy, who holds joint appointments at Temple University's School of Medicine and its Beasley School of Law, and who is a former chief of staff for the Pennsylvania Department of Health. "What are we going to do to change that mind-set?"

The answer, according to participants at a workshop Thursday at Temple: Train people who know the cycle of violence personally, so they can stop it from spreading.

People like Marcus McAllister, who stars in a documentary shown at the training session, sponsored by Cure Violence. Started in Chicago in 2000, the program now has offshoots around the nation, including Philadelphia CeaseFire, which started in 2011.

Programs that use the Cure Violence model have been shown to help reduce shootings and homicides, according to independent evaluations by the federal Centers for Disease Control and Prevention, Johns Hopkins University, and the Center for Court Innovation, along with the Bureau of Justice Assistance in New York.

"I come from the gang lifestyle," McAllister said in the video. "I can relate with making bad decisions."

After 10 years in federal prison, McAllister is now a national trainer with Cure Violence. The video shows him in a suit, with a family and a good job - a 180-degree turn from his old life.

The people McAllister and others are training - known as "violence interrupters" - can do their work in many ways. In Philadelphia, CeaseFire has people canvassing the streets using crime data to figure out where trouble might occur. Its latest project is a partnership with trauma centers at Temple University Hospital, Einstein Healthcare Network, and Penn Presbyterian Medical Center to reach crime victims and convince them that retaliation is not the way.

Linda Rich, director of education and consultation at Drexel University's Center for Nonviolence and Social Justice, is involved with another program that complements CeaseFire.

"There is a greater message that is being sent by Philadelphia. The Department of Behavioral Health is funding both these programs," she said. "Philadelphia is saying, we care about the people in the communities."

Funding for the Philadelphia CeaseFire program comes from an initial $250,000 grant from the Pennsylvania Commission on Crime and Delinquency and a three-year grant for $1.5 million from the federal Office of Juvenile Justice and Delinquency Prevention.

"We have about 20 or so police districts, but this notion of violence only occurs in about eight of them," Davis Bellamy said. "These residents have been constantly exposed to it, so it's second nature. That's all they know."

Gary Slutkin, CEO of Cure Violence, said exposure is key to how violence spreads, much like contagious diseases.

"Growing up in the community I grew up in, people [imitated] you, they do what you do," said Cobe Williams, a national trainer for Cure Violence. "I get mad at a certain individual, and as soon as I get mad, my whole block is mad at him. Just because."

Slutkin said violence fits the medical definition of a disease: "It is a characteristic set of signs and symptoms. It results in people being less healthy. And people [exposed to violence] are more likely to have a death or some type of disability."

CeaseFire, like Cure Violence, uses violence interrupters to ease tension in areas that need it most. The 10 interrupters were recruited from the neighborhoods they serve, and are full-time employees of Temple University School of Medicine.

"Several of our outreach workers are those who've had a criminal past," Davis Bellamy said. "They have an immediate rapport with those young people who have made some bad decisions. But they can relate. It's an immediate connection. Through that, they're able to mentor them."