America's murder problem could be solved by this brilliant new insight

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In Richmond, California, a revolutionary approach of reframing violence as a disease led to 76% reduction in the murder rate in only seven years — all it took was identifying the people most likely to "carry" the disease of violence, then offer them the structure to not fight.

Now data from Michigan State University suggests that violence-as-disease isn't just a useful analogy. 

A new study published in the Journal of American Public Health found gang-related homicides clearly spread throughout Newark, New Jersey, via channels typically found in disease transmission.

Between 1997 and 2005, researchers collected data on where gang violence popped up in the Newark area. They found it began in one neighborhood and gradually moved to — or infected — the neighborhoods surrounding it.

While homicide rates are declining in the US overall, cities like Washington, D.C., Chicago, Milwaukee, and New Orleans have all seen surges in recent years. If each violence-prone city begins focusing on making criminals less violent rather than quarantining them in prison, the new research suggests, those "murder capitals" could quickly become safer places. 

When viruses spread, infectious agents like bacteria and viruses infect certain everyday mediums: the water we drink, the food we eat, and the air we breathe.

In gangs, according to lead author of the study April Zeoli, the infectious agents could be the gang's sense of pride or demand for respect. Those get transmitted through word of mouth or other publicity, Zeoli says. When they "infect" a susceptible area, what often breaks out is violence.

Zeoli and her team initially considered the idea that violence is contagious in 2012, with a study published in Justice Quarterly. It was among the first evidence to suggest that law enforcement could track the spread of crime by treating it like disease.

"By using the principles of infectious disease control ... we may be able to prevent homicide," Zeoli and her coauthors wrote.

Rather than deter crime through harsh jail sentences, communities could use the data on how violence spreads to predict where problems will emerge and send help to those neighborhoods.

In practice that process involves a few steps, including:

• Public health workers discovering the underlying risk factors by which some people are immune or susceptible to joining gangs.
• Increasing the susceptible population's resistance to committing violence through the deployment of case workers and other creative crime-deterrent strategies, like paying criminals not to commit crimes.
• Addressing individual and environmental conditions that lead to the spread of gangs and violence, such as drug trade and poverty.

Other solutions to homicide are more large-scale.

In Australia, a brutal string of massacres reached a boiling point in 1996, leading the Australian parliament to ban the import of all automatic and semiautomatic guns. It also destroyed some 700,000 guns between October 1996 and September 1997.

The US would have tens of millions more guns to destroy if it wanted to reach Australia's level of safety, but research suggests a simple change in attitude could be a huge first step.