How will soldiers combat Ebola? What's going on?

Something more than just the  Ebola crisis is going on and we puny nobodies will not get the whole picture (if ever) from the powers-that-be.  Why would the USA send 4000 soldiers to Liberia? Soldiers to fight a disease? Presumably, the troops are building treatment units. Really? Wouldn't it have been far more constructive to give the contract for those units to a construction company ... a construction company based in

Liberia itself?  And, now we hear that the British are sending 91 army medics to join 40 UK soldiers already there.  Why are soldiers required in plague hit areas? Why is an RN ship also on its way there?  
I don't get it.  Too many questions and no logical answers. What are the powers-that-be not telling us? 
Has the Ebola crisis been too good an opportunity for USA and UK to blackmail the governments of that strategic port area of west Africa for a military foothold in that region?  Under the guise of doing good, a whole lot of evil can be accomplished very, very easily.

From BBC:
Ebola crisis: British army medics  travel to West Africa
British army medics are on their way to West Africa to help in the fight against the deadly Ebola virus.
A team of 91 medics from 22 Field Hospital in Aldershot will run a hospital in Sierra Leone, set aside for healthcare workers who risk infection.
The nurses, doctors and infectious disease consultants will join 40 soldiers already in the West African country.

Ebola has killed more than 4,500 people, nearly all in West Africa.
The British medics are travelling ahead of the departure of Royal Navy ship the RFA Argus on Friday.....

From WSJ:
After almost a month in Liberia, U.S. troops have completed construction on a 25-bed medical facility to treat health-care workers who come into contact with Ebola and are running five mobile labs that expedite tests for the deadly virus.

The Pentagon effort against Ebola will enter its next phase this weekend, when the head of the American military’s 101st Airborne Division, Maj. Gen. Gary Volesky, arrives in Liberia to take over the U.S. effort. The Kentucky-based Army division will send about 700 members who will join up to 4,000 others to finish building 17 treatment units with more than 100 beds each, and to train hundreds of medical workers..........