Foreign Policy has a list of 10 stories you might have missed over the past year. This one is misleading: "Mexico's Drug War Moves South." It details how "Mexico's" war has started to hurt Central America.
Until now, the cocaine itself has been processed almost exclusively where coca is grown in the Andean region of South America. But in March, the first cocaine-processing lab ever discovered in Central America was found in Honduras. In El Salvador, which has also seen its crime rate skyrocket, Sinaloa and the Zetas are believed to have established alliances with local gangs such as the infamous Mara Salvatrucha.
This isn't just Mexico's drug war anymore.
The problem is that this is a crisis that has moved northward, not southward. Coca is not grown in Mexico, and cocaine is not processed--yet, anyway--in Mexico. We're just seeing more balloon effect, dating way back to the 1980s in Bolivia. As long as demand remains high, then various aspects of drug trafficking move around the region, with the constant creation and destruction of DTOs, both large and small.
Lastly, we always need to remember that drug demand in the United States largely fuels this, so it is not "Mexico's war" any more than it was "Colombia's war." Regardless, it did not start in Mexico and then flow south.