An outbreak of Ebola that has already killed 70 people prompted Senegal to close its border with Guinea on Saturday in hopes of preventing the deadly virus from spreading.

Senegal officials closed the border, as well as a popular market that attracts people from the neighboring countries, according to the Associated Press.

Most of the cases were reported in the southern portion of Guinea, a country in west Africa.

While outbreaks are not entirely uncommon in certain parts of Africa, confirmation that the virus had spread to Guinea's capital city of Conakry caused serious alarm, Reuters reported. Authorities said those infected had been put into quarantine.

Ebola is extremely contagious, moving easily from person to person. It is typically contracted through physical contact with infected people or contaminated objects like needles, although there has been concern in the past that some types of the virus can be transmitted through the air.

Tests of victims with hemorraghic fever, a type of illness that usually causes fever and bleeding disorders, and can be caused by a variety of pathogens such as the hantavirus or dengue fever, confirmed that Ebola was the cause of the recent outbreak. The most notable symptoms include bleeding from the eyes and ears.

Ebola is categorized as a biosafety level 4 pathogen — considered the most dangerous in the world. Once contracted, Ebola is highly fatal, with a fatality rate that can reach as high as 90%, according to the World Health Organization.

The virus first emerged in the 1970s, with a series of outbreaks in the 1990s and early 2000s. A severe outbreak in 1995 caused 245 deaths in Kikwit, a city in the Democratic Republic of Congo.

There is no vaccine or cure for Ebola.

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