What is the conflict that's causing such a high rate?

I associate Col/Mex deaths with cartels warring over trafficking routes but what is happening in Brazil? Is it just street trade?

Brazil has 3 national-level drug cartels that are in their own mini-war. Besides that, some cities (like Rio and São Paulo) have many local cartels that constantly fight over territory.

Col is a producer, Mex is a route to the US, Brazil is a route to Europe

Normal business disputes are settled through the courts (or the threat of the courts). Disputes related to illegal business are settled through violence. The state benefits by maintaining a base level of violence, so it always keeps some popular industries outlawed.