The World Health Organization says the worst outbreak for 30 years has spread from the capital Luanda to most coastal and central regions. The disease has killed several hundred people since December.
The UN's health body said that over 2,500 suspected cases had been reported in Angola in recent months, adding that the disease had also spread to the Democratic Republic of Congo, Kenya and even China.
The latest outbreak, the first significant flare-up since 1986, was first detected in the capital Luanda at the end of last year, and has now been confirmed in several other regions of the southern African country.
In an update released Thursday, the WHO said:"Despite vaccination campaigns in Luanda, Huambo and Benguela provinces, circulation of the virus persists in some districts."
The health agency warned of unimmunized travelers spreading the virus after neighboring DR Congo reported 41 cases imported from Angola, with two cases in Kenya and 11 in China.
"The outbreak in Angola remains of high concern due to persistent local transmission in Luanda despite the fact that more than seven million people have been vaccinated," WHO said.
Can be deadly
Yellow fever is aviral hemorrhagic disease transmitted by infected mosquitoes. Symptoms include a mild infection with fever, back pain and fatigue.
But in 15 percent of cases, a second, toxic phase is experienced. This can lead to bleeding in the mouth, eyes and gastrointestinal tract. Around 20 percent of those who experience the toxic phase die.
Although there is no specific treatment for yellow fever infection, vaccinations are recommended for travelers to tropical regions of Africa and Latin America's Amazon region.
Aid groups say poor health facilities and vaccine shortages are limiting Angola's ability to cope with the outbreak.
The WHO said 2.4 million doses of the yellow fever vaccine have been received and a further 2.6 million people will be receiving a jab in the next few weeks.
mm/kms (AFP, WHO)