As tor the 'troll farms', I imagine that since the advent of social media 'trolls' are a worldwide phenomenon, with many of them more developed countries using it as a political tool.
Internet troll; "In Internet slang, a troll (/troʊl, trɒl/) is a person who sows discord on the Internet by starting quarrels or upsetting people, by posting inflammatory, extraneous, or off-topic messages in an online community (such as a newsgroup, forum, chat room, or blog) with the intent of provoking readers into an emotional response or of otherwise disrupting normal, on-topic discussion, often for the troll's amusement.
This sense of both the noun and the verb "troll" is associated with Internet discourse, but also has been used more widely. Media attention in recent years has equated trolling with online harassment. For example, the mass media have used "troll" to mean "a person who defaces Internet tribute sites with the aim of causing grief to families". In addition, depictions of trolling have been included in popular fictional works, such as the HBO television program The Newsroom, in which a main character encounters harassing persons online and tries to infiltrate their circles by posting negative sexual comments."