West African Ebola strain less aggressive than prototype strain from 1976

West African Ebola strain less aggressive than prototype strain from 1976 | Courtesy of

According to a recent report from the National Institutes of Health (NIH), the current strain of the Ebola virus that is circulating through West Africa is called the Makona strain and is less aggressive than the original Mayinga strain that, which was isolated in Central Africa in 1976.

When compared to the Mayinga strain, the Makona strain takes approximately two additional days to start terminal disease in an animal subject. This is an important discovery to scientists, as they wonder whether the Ebola strain in West Africa will grow more severe over time.

The test subjects were cynomolgus macaques. Researchers used these animals to model disease and infection in humans. The scientists infected three macaques with the Mayinga strain from 1976 and an additional three with the Makona strain from 2015.

Within three days of receiving the infection, both animal groups showed signs of shedding the virus. However, the Mayinga group did show a rash beginning on day four and grew seriously ill on days five and six, while the Makona group began to develop a rash on day six and grew seriously ill on days seven and eight.

In addition, the liver damage common to Ebola disease was also delayed approximately three days for the Makona group -- but not the Mayinga group.

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