What is the Ebola Sudan strain?

The Ministry of Health on Tuesday declared that the Ebola outbreak in the central Mubende District is of the Sudan variant, different from the Zaire type ravaging eastern Democratic Republic of Congo (DR Congo).
The Ebola Sudan was named because the virus causing it was first discovered in the southern part of Sudan, present-day South Sudan, in 1976. 
The World Health Organisation (WHO) initially categorised Ebola, whose name derives from River Ebola in former Zaire, now the DR Congo, as a hemorrhagic fever before revising it to Ebola Virus Disease (EVD).

According to the global health watchdog, Ebola Sudan is a single member of the Sudan ebolavirus species and one of the six known viruses within the genus Ebolavirus, and one of the four that causes EVD in humans and other primates.
The first known EVD of the Sudan variant was registered on June 27, 1976, and 151 of 284 infected persons died.
The disease cannot be differentiated from others caused by other ebolaviruses by just clinical observation alone.
This newspaper broke the story of the outbreak of Ebola in Uganda before the government confirmed it on Tuesday. 
In a statement, WHO’s Africa office said it was helping Uganda’s health authorities with the investigation and staff deployment to the affected area.

The WHO said there had been seven previous outbreaks of Ebola Sudan strain, four in Uganda and three in Sudan.
It said Uganda last reported an outbreak of the Ebola Sudan strain in 2012 and an outbreak of the Ebola Zaire strain in 2019. 
Currently, unlike Ebola Zaire, there is no vaccine against the Sudan strain.
The global health watchdog statistics show that four in every 10 persons infected by the Ebola Sudan strain die, but early initiation of supportive treatment is known to reduce the fatality rate.