text_1: A 100g dose of chloroquine chemoprophylactic regimen results in retinal toxicity after 5-6 years of weekly intake.
text_2: OBJECTIVES To examine the risk of malaria in long-term travelers, recent developments in personal protective measures, and the safety and tolerability of malaria chemoprophylaxis during long-term use and to consider prevention strategies including continuous chemoprophylaxis, stand-by emergency self-treatment, seasonal prophylaxis, and strategies to prevent primary infection and relapses from P vivax malaria.