Juba - Cholera has killed seven people in the South Sudan capita of Juba, the head of the isolation ward at the nation's main public hospital said on Monday.At least 37 cases of cholera have been confirmed but the Health Ministry has not yet declared an official outbreak, according to Dr Thomas Wel Maker of Juba Teaching Hospital.Dr John Rumunu, director general of preventive health at the ministry, told a meeting of the country's cholera task force that "probably we are dealing with cholera outbreak" but it wasn't up to him to make the declaration.Cholera is a fast-developing, highly contagious infection that causes diarrhoea, leading to severe dehydration and possible death.There have been 18 other suspected cholera cases in a camp for displaced people in Juba, according to Alejandro Guzman of the International Medical Corps, who is leading the response in the camp.Guzman said they are still waiting to hear from the ministry if these cases have been confirmed as cholera. He said they submitted their samples over the last two weeks.According to World Health Organisation guidelines, a cholera outbreak should be declared when there are 10-20 cases.The ministry had been expected to declare an outbreak on Monday, but the event was cancelled abruptly and no reason was given."The information is still not out there," Maker said in the Monday meeting for the country's cholera task force. "Many people don't know what we are dealing with."Last year a cholera outbreak in South Sudan infected more than 6 000 people and killed 167, according to WHO figures.