An outbreak of yellow fever that started in Angola in December has spread to at least 16 other countries threatening to hurt travel business in Africa the way the Ebola virus in West Africa did a few years ago.

This is the worst yellow fever outbreak recorded in over 30 years and has already killed 238 people  and affected thousands others in several countries in sub-Saharan Africa, including Angola, Uganda, Rwanda and the Democratic Republic of Congo, Independent reported.

Other countries where the disease has been exported by traveller from Angola include China and Kenya.

According to the World Health Organization (WHO), yellow fever whose symptoms include vomiting, fatigue, severe headache and nausea and could leading to organ failure and death, has no specific treatment apart from vaccination.

Countries where there are Aedes mosquitos, carriers of the yellow fever virus, are particularly at risk. Areas where there have been previous outbreaks of Dengue, Chikungunya or Zika virus are also fertile grounds for the disease to spread.

WHO has warned that if the disease is not checked in time it could become a “threat to the entire world”.

“The evolution of the situation in Angola is concerning and needs to be closely monitored,” WHO stated in a report, adding that he large number of expatriates living in Angola could easily spread the disease to other parts of the world.

In Southern Africa, Namibia and Zambia are on high alert of an outbreak of the disease, while in East Africa travel between Kenya, Rwanda and Uganda, which use a single visa, has been affected by cases of travellers being detained at the border for not having proper yellow fever vaccine certificates.

Rwanda has gone ahead to administer yellow fever vaccinations on arrival for those without the required certificate at a $40 per jab fee, Traveller24 reported.

Travelers from Africa or Latin America arriving to Asia must have a certificate of yellow fever vaccination and if there are medical grounds for not getting vaccinated, International Health Regulations require that this must be certified by the appropriate authorities.