The World Health Organization says the number of cholera cases in Haiti is expected to exceed 500,000 by the end of 2011.
The U.N. health agency says some 470,000 cases and 6,600 deaths have so far been recorded.
WHO cholera expert Claire-Lise Chaignat told reporters in Geneva on Friday that the disease was also likely to become endemic in the Caribbean nation.
No cases of cholera had been documented in Haiti before the outbreak a year ago, months after a devastating earthquake hit the country.
Chaignat says WHO is examining whether a large-scale cholera vaccination campaign is possible in Haiti.