The death toll¹ from cholera² across Haiti has risen to 644, as aid workers fight to contain the spread of the disease in the capital, Port-au-Prince.

海地霍乱死亡人数已经上升至644，救援人员正在全力制止该疾病在首都太子港的蔓延。

At least 10,000 people suffering from cholera（霍乱） are in hospitals across the country.

Doctors in Port-au-Prince say they are alarmed at the speed at which new cases are emerging.

A senior health ministry³ official said the epidemic⁴ was now "a matter of national security".

The ministry on Tuesday confirmed the disease had reached Port-au-Prince, which had feared an outbreak since October.

About 170 people are now being treated in hospitals in the city, according to the Pan-American Health Organisation⁵ (Paho). One person has died.

'Cross the border'

Dan Epstein, a Paho spokesman, said the organisation expected 270,000 Haitians to be infected by the disease in "between six months and a year", according to modelling based on a past outbreak in Peru.

"What's really important to us now is the trend of where it is and the long term trend of where it is going to be," he told the BBC.

"Its hard to predict the impact. But it's very likely that cholera is going to be in Haiti for a while," he added.

Paho has warned that there is a real risk of the epidemic crossing the border into the neighbouring Dominican Republic.

The organisation says that trying to educate the population about prevention and treatment of the disease, thereby⁶ reducing the fatality⁷ rate（死亡率） of the disease in the Caribbean country, remains⁸ a priority.

The disease broke out in the Artibonite River valley in central Haiti in mid-October and initially⁹ seemed to have been contained, but cases have since soared（飙升） .