* Conakry government says making progress after spike in new cases
* U.S. Department of Defense opens Ebola testing lab in Liberia
* Gambia bans flights from Guinea, Liberia and Sierra Leone
By Saliou Samb
CONAKRY, April 15 (Reuters) - The number of deaths caused by Ebola has slowed dramatically in Guinea and the outbreak is nearly under control, the country's health ministry said on ...