Kenyan health authorities on Sunday declared a yellow fever outbreak after the death of three people and the detection of 15 other suspected cases in the northern county of Isiolo.
The health ministry said it had dispatched a rapid response team to the area and others in a bid to fight the disease.
“We will prioritise vaccination in at least another half a dozen neighbouring counties now placed on red alert,” the ministry said.
Yellow fever is caused by a virus transmitted to humans by mosquitoes.
In most cases, symptoms include fever, chills, loss of appetite, nausea, muscle pains particularly in the back and headaches.
The last yellow fever outbreak in Kenya was in 1992/1993.