Kenya has reported two out of three suspected cases of yellow fever after a patient died of the disease in Nairobi.

The Ministry of Health has scaled up surveillance, calling on Kenyans to be on the lookout for symptoms and report cases to the nearest health facility.

According to the ministry, laboratory investigations conducted at the Kenya Medical Research Institute (Kemri) tested positive for yellow fever antibodies and negative for Ebola and Marburg for the patient who died.

Investigations for the other two cases tested positive for one, and negative for the other.

The two patients confirmed to have the yellow fever virus had returned from Angola where there has been a flare up of the disease that has killed more than 250 people since last December.

Nairobi County Executive in charge of health Bernard Muia has said the patient who tested positive for the disease is undergoing treatment.

In Kenya, yellow fever cases were last reported in 1999 in the Rift Valley where the disease is endemic.

Angola has been reporting nearly 900 suspected cases each day. The Ministry of Health says it recorded 76 suspect cases and 10 deaths in three days alone this month, but gave no overall toll.

Following this, Kenya has been on high alert for yellow fever, increasing surveillance at all entry points especially for people travelling from Angola.

Yellow fever symptoms include severe headache, nausea, vomiting and fatigue, according to the World Health Organisation. The disease can enter a toxic phase in some people, leading to organ failure and death.

Poor sanitation is being blamed for stoking the outbreak, by providing fertile breeding grounds for the mosquitoes.

Angola, like Kenya, lies in the yellow fever belt of Africa where vaccination against the disease is recommended. Since the second half of 2015, yellow fever virus circulation has been reported in Mali and Ghana.

There is no specific treatment for the viral haemorrhagic disease which is transmitted by infected mosquitoes and found in tropical regions of Africa and Latin America's Amazon region.