A yellow fever outbreak in Sudan's Darfur region has killed 107 people in the last six weeks, the World Health Organisation reported, warning that the disease could spread all over the country.
The number of deaths from the outbreak is steadily rising, and Sudan is working on an emergency vaccination drive, WHO said on Tuesday.
Officials reported last week that 67 people had died in the outbreak.
There is no medicinal cure for yellow fever, which is spread by mosquitoes. Doctors treat the main symptoms - dehydration, fever, bleeding and vomiting - and wait for the viral infection to pass.
As part of the emergency response programme, 2.4 million doses of the yellow fever vaccine are scheduled to arrive in the Sudanese capital next week, Dr. Anshu Banerjee of the WHO office in Sudan told AP.
More than 350 suspected cases of yellow fever have been reported in Darfur since late September, and more than 30 per cent of people showing symptoms have died, according to a WHO statement.
Around 70 per cent are under the age of 29, according to a statement released on Monday by the Sudanese Health Ministry and the WHO.
Banerjee warned that yellow fever cases are "definitely spreading" to new areas of the remote region of Darfur, where Sudan's government has been battling rebel groups since 2003.
More than 300,000 people have been killed in the conflict, and health care services are not available to many residents as a result of the turmoil.
He said that while no yellow fever cases had been found outside Darfur, the WHO is planning a risk assessment in the next two weeks on the assumption that all areas in Sudan may be at risk of infection.
Banerjee said that Darfur's heavy rainy season this year created additional breeding sites for the disease-carrying mosquitos.
Sudan's last outbreak of yellow fever killed 160 people in the South Kordofan region in 2005.
The WHO estimates that more than 500 million people in 32 countries in Africa are at risk of yellow fever infection.