A yellow fever outbreak in Sudan\'s Darfur region has killed 127 people as of Thursday, the World Health Organization (WHO) reported Friday. In all, 537 suspected cases of yellow fever have been reported and nearly half of localities across Darfur have been affected by the disease. WHO spokesman Tarik Jasarevic said the local authority has received 2.4 million doses of yellow fever vaccines together with injection supplies and an emergency vaccination campaign has begun. The areas that have reported most cases have been supplied with required blood units and laboratory supplies necessary for blood transfusion, according to Jasarevic. He said his agency has also sent a mission team of experts to the area to investigate the source and spread of the outbreak with the Federal Ministry of Health in Sudan. Yellow fever is an acute viral hemorrhagic disease transmitted by infected mosquitoes. There are an estimated 200,000 cases of yellow fever, causing 30,000 deaths worldwide each year.