At Balukhali refugee camp, unclean water, cramped living quarters and squalid conditions create the prime environment for outbreaks of preventable diseases.
Accounts support accusations of widespread rape by Myanmar's army; the government rejects the claims.
Registering children and tracing their families is first priority for aid groups but with more than 500,000 arrivals, the task is daunting.
Air quality is a problem every year caused by excessive field-burning in the region during the dry season - though this year’s smoke arrived early.
Despite Thai government’s rush to aid tourist areas, relief was slow for hardest-hit villages, comprised largely of unregistered Burmese fishing laborers.
Human rights groups are focusing attention on ongoing forced detentions, restricted movements and intimidation of more than 120,000 displaced ethnic Rohingya.
Parasite adapts resistance to treatment in Cambodia, Vietnam, Thailand, Myanmar and Laos.