Hospitals are where ebola really gets going in africa. The various strains of ebola go from approx 25pct fatal to 90pct fatal even with first world medical intervention.
What I have read that they are separate species of ebolavirus, not strains.
A strain would be a modified species, such as if
Zaire ebolavirus mutates with a stronger protein coat and can live for hours outside the host, then it would called
Zaire ebolavirus xyz (xyz would be the name given to the strain, usually the discoverer or location 1st found). Genetically the strain matches the species but is different in that a couple genes may be expressed or not.
Flu is usually strains since it a the same species of the flu virus, just has different genes turned on, this is why some years of the flu outbreaks are worse than others. Think Darwinism.
Easiest way is to think of corn,
Zea mays and all the different non GMO Hybrids that are available. Each non GMO plant is slightly different though inbred single cross breeding, but still will test as corn. GMO corn, each plant could be looked at a different species since genetic material has been added to the germ plasm to get the plant to have traits that would not occurred in corn no matter how you crossed it, such as herbicide resistant or producing Bt (rootworm control).