Why would you infer that? Six out of 150-200,000 may be much better than the sequelae of malaria if all these people are untreated. My Multum Clinical Database does say, however, that chloroquine is the CDC drug of choice.
Slings, yes, you can take it with a grain of salt, but transient nervous system side effects are relatively common and psychiatric side effects are also relatively common, perhaps as part of acute brain syndrome. So, it's not so far-fetched.