THAINGKHALI, Bangladesh (AP) -- U.N. agencies say they have begun a massive cholera immunization campaign to stem a possible outbreak of the water-borne disease among more than a half million Rohingya Muslims who have fled violence in Myanmar to neighboring Bangladesh.
No cases of the potentially life-threatening diarrheal disease have yet appeared in makeshift camps in Bangladesh.
UNICEF says the vaccination campaign starting Tuesday involves 900,000 doses delivered by more than 200 mobile teams, making it the second-largest oral vaccination campaign of its kind, after another in Haiti last year.
The World Health Organization has tallied some 10,000 cases of diarrhea among the refugees, and says unhygienic and cramped conditions raise the potential for a cholera outbreak.
The U.N. refugee agency says Bangladeshi border guards reported over 11,000 Rohingya refugees crossed the border Monday.