There were no official US MWD casualties during WWI as the program did not exist at that time.
The statics for all MWD's used during WWII, and their disposition can be found by accessing the "The United Stated Army Medical Corps History" on line and typing in the key word "War Dogs".
I have no idea about the dogs used by the US Army during Korea, but for sure there were no USMC dogs there.
The names and statics for all MWD's that served in Thailand, and Vietnam can be found on the Vietnam Dog Handler Association's website, and several others for that matter.
We know that during the past 10 years Special Operations Forces (SOF) have officially lost 59 MWD's killed in action.
At the moment I do not know of a location that gives all the statics on Iraq, or Afghanistan.