DAR ES SALAAM, May 10 (Xinhua) -- Tanzania on Thursday issued an alert following an outbreak of the Ebola virus disease in the Democratic Republic of the Congo (DRC).

Ummy Mwalimu, the east African country's minister for health, said the government has directed regional medical officers across the country to strengthen surveillance in an effort to prevent the Ebola outbreak in the country.

"The Tanzanian government has received an official report on the outbreak of the deadly Ebola in the in DRC," Mwalimu told a news conference in the capital Dodoma.

She said Tanzania has, until now, not documented any case of Ebola, but insisted that the country was not immune from the viral disease due to the possibility of cross-border transmission from the affected countries.

"We must strengthen our border surveillance. The fact that no case has ever been reported in our country doesn't mean we are safe," said the minister.

With this reappearance of the Ebola outbreak, the DRC is at its ninth Ebola outbreak since 1976. The last outbreak recorded by the country took place in May 2017 in the northern province of Bas-Uele, which killed four people.

The Ebola virus is highly contagious and causes a range of symptoms including fever, vomiting, diarrhea, generalized pain or malaise and in many cases internal and external bleeding.

Mortality rates of Ebola fever, according to the World Health Organization, are extremely high, with the human case-fatality rate ranging from 50 percent to 89 percent, depending on viral sub-type.