N'Djamena - The Chadian government said on Thursday that more than 50 people have died of cholera in Chad where authorities have since declared an outbreak."We count 312 cases, including 52 deaths," said health ministry secretary-general Hamid Djabar.Authorities declared a cholera outbreak on Monday, which put in place a "crisis committee" to monitor the situation and to strengthen cooperation with partners such as medical charity Doctors Without Borders (MSF) and the UN children's agency Unicef."For the time being, the outbreak is confined to the region of Sila" near the borders with Sudan and the Central African Republic, said Djabar.In the neighbouring region of Salamat, 19 cases and two deaths were recorded, but the health ministry said the situation is "under control".Health authorities discovered the presence of the cholera virus in the east of the country in mid-August following two deaths from acute diarrhoea and vomiting.The cholera virus, which can kill within a few hours if left untreated, regularly affects the east and the Lake Chad basin, the least developed areas of the country where half the population lives below the poverty threshold."In 2011, Chad, along with other countries in Sub-Saharan Africa, was affected by a large-scale cholera outbreak. More than 450 deaths and a total of 17 200 cases of the disease were reported," MSF said on its website.A similar outbreak was also discovered in neighbouring Nigeria, where the UN said Monday that at least 44 people have died of the disease in the northeast of the country.The first cholera case in Nigeria was identified in Borno State also in mid-August and has since spread, mainly in camps for those displaced by the Boko Haram insurgency."According to estimates, there are 1.3 to 4 million cases of cholera every year, and 21 000 to 143 000 deaths due to the disease worldwide," the World Health Organisation said in July.