The violence virus

IN URBAN areas across our nation, hardly a day goes by without news of a shooting. Many such incidents start with a rash argument between young people armed with guns. The typical response, when shootings increase, is to enhance law enforcement, but that is only part of the solution.

This deadly cycle of shootings is a public-health epidemic. By approaching it as such -- as a contagious disease of underlying expectations and pressures, one that is both treatable and preventable -- we can make significant progress toward halting it.

Urban violence is spread largely by expectations among youths in many gangs: If you insult or harm me, I must harm you. That powerful peer pressure and behavior is transmitted, like a virus, from person to person and gang to gang -- until there's a violent outbreak, and someone is killed. Then the virus is quiet until another outbreak .

A number of impressive efforts to prevent such violence are under way in Boston. But the benefits of shifting from law enforcement alone to community efforts to make violence unacceptable have become especially clear in Chicago -- because of that city's CeaseFire program, a public-health approach with some roots in an earlier Boston effort.

As former dean of the School of Public Health at the University of Illinois, Chicago, I have seen firsthand how CeaseFire has identified the pressures driving violent behavior and used community-based interventions to alleviate those pressures and modify behavior.

Gary Slutkin, the UIC epidemiologist who founded and directed Chicago CeaseFire, drew on his experience in epidemic control for tuberculosis, AIDS, and cholera. He adapted the program from selected violence-reduction practices of several cities -- including Boston's Ceasefire, an innovative 1990s program to reduce gun violence -- as well as from international practice in reversing epidemics.

One key component of the program is the use of street-smart outreach workers . Street outreach workers come from troubled neighborhoods and work to change the street behavioral norms. Many outreach workers have been gang members in the past and some have spent time in prison. But they are committed to a new lifestyle and want to help the youth in their neighborhoods.

Carefully selected for their intimate knowledge of what motivates an urban youth to shoot, then trained by violence prevention experts, these "violence interrupters" get plugged into the street grapevine to understand who might be seeking revenge. When they identify a troubled youth on the verge of seeking vengeance, they work to draw him into thinking about the devastating consequences of retaliation for himself and his family. Many times, building that relationship is enough. If that fails, and violence occurs, the workers head to the hospital to talk to the victim's friends and try to squelch ideas of retaliation.

Like the street workers in Boston and elsewhere, Chicago outreach workers also offer the youths alternatives to violent life, such as school or job training through community organizations. In 2006, outreach workers helped mediate numerous conflicts, made more than 8,000 visits to youths' homes, and helped hundreds of the highest-risk youth get back into school or into a job.

These interventions work. After the Chicago CeaseFire model was implemented in 2000, the second-most-violent police beat in the city saw a 67 percent decrease in shootings. Replications of the program in six other parts of the city produced an average reduction in shootings of 45 percent. Chicago's shootings dropped to the lowest level in 40 years in 2004. The program is now being adopted by other cities around the country, and CeaseFire workers in Chicago are seeking to expand the campaign there.

Much like the concerted effort to change people's norms around drunken driving or smoking, a successful anti violence campaign needs a single message with multiple messengers.

These are the ingredients for success: Neighborhood and religious groups that can work with police, schools, and public-health and social-service experts to change the norms that feed violence. A trained network of former gang members who understand the underlying issues, keep a pulse on potential conflict, and step in quickly to negotiate. Strong financial support from federal and local government and from business leaders. A neutral organization such as a university to help draw together groups from across a city and state .

In Boston and other urban areas, concerned people are working together to stop the escalating violence. Approaching urban shootings as a preventable public health epidemic is one crucial way to help strengthen neighborhoods, give at-risk youth a future, and make our cities healthier.

Susan C. Scrimshaw is president of Simmons College in Boston.