An outbreak of the deadly Marburg virus has intensified in Angola, causing a death toll of about 150. Countries bordering Angola have put in place preventative measures to stop the virus from spreading across the region.

West African countries like the island state of Sao Tome and Principe are among nations that have put the strict measures in place.

Sao Tome's Health Ministry says that all passengers who come into Sao Tome from Angola will remain under medical watch for three to 10 days, the incubation period of the virus.

The epicenter of the current outbreak is in the northern Angolan province of Uige, which is near Gabon, and borders the Democratic Republic of Congo.

The Gabonese director general of health, Kombila Terendez, says the government has issued an alert to all airplanes warning passengers about the symptoms of the disease.

Although authorities have not stopped people from crossing the borders by land, there are teams set up to interrogate people and see if they show symptoms. The Gabonese government is also sending teams into villages to try and educate people about the disease, as well as handing out information leaflets on its borders.

International health agencies are training local staff in the region to recognize the disease which initially mimics the symptoms of severe flu or malaria.

No cases outside Angola have been confirmed by international health agencies, but there have been local reports of suspected deadly cases in both the Democratic Republic of Congo and the Republic of Congo.

There is no cure for the Marburg virus which causes bleeding and fever, and in some cases causes the victim's skin to peel off. It is spread through touch and direct contact with body fluids..

The International Red Cross is working with health agencies in the region to try and educate people about how the disease is contracted.

A doctor who has worked amid similar epidemics before, Harkan Sandbladh, says that although people in the region cross borders everyday to work in other countries, diseases like Marburg tend to be locally contained.

"It is just having outbreaks every half year or one year apart and also then it seems to kill itself sort of. It is self dying. So actually what we have seen so far in all the outbreaks is that it is locally contained," he said.

Dr. Sandbladh says people are unlikely to travel once having contracted the virus because they fall ill very quickly.

Some people survive the Marburg virus, but it is not yet known why. Seventy-five percent of cases in this current outbreak involve children under the age of five.