Scientists from the Centers for Disease Control and Prevention (CDC) have identified active circulation of Marburg virus in bat colonies for the first time in Sierra Leone, according to a study published today in Nature Communications. CDC scientists and partners found that 2.5 percent of 435 Egyptian rousette fruit bats tested from four districts in Sierra Leone tested positive for Marburg virus. Some of the infected bats had a strain similar to the one seen in Angola in 2005, thought to be the most virulent strain of Marburg virus that has emerged thus far. During the 2005 outbreak, 9 out of 10 people who contracted the virus died. In contrast, during the 2014-2016 West African Ebola outbreak, 4 out of 10 people reported ill later died. Ebola and Marburg are in the same family of viruses.
This new study is the first time Marburg virus has been found in West Africa and the first time an Angola-like strain has been found in Egyptian rousette bats.
Actively infected bats can potentially spread the virus to people who interact closely with them, including eating them for food or eating fruit that’s been contaminated with infected bat saliva or urine. Egyptian rousette bats are a type of fruit bat that can carry Marburg virus. They eat many kinds of fruit, including types that are also preferred by people. To date, there have been no Marburg outbreaks in people in Sierra Leone. But the presence of the virus in bats means spillover to people is possible. CDC has been working closely with partners in Sierra Leone to educate residents how to live safely with Egyptian rousette bats and avoid becoming infected. Bats have important environmental benefits and the best way to prevent contracting Marburg infection is to avoid the bats and not injure or kill them, or consume partially eaten fruit.
The study, which is available hereexternal icon, was done in coordination partners at the Njala University in Sierra Leone, the One Health Institute at the University of California Davis, and their partner the University of Makeni, also in Sierra Leone.