Greetings,
I'm currently working on my MPH&TM (tropical medicine). In 2000 I completed a diploma in tropical medicine at Tulane and spent a year volunteering in Ethiopia. I plan to go back to Africa when I finish my MPH.
You really don't need an MPH to do some of the things you've mentioned, but if I didn't think it was a good idea, I wouldn't be here now.
You might want to look into Doctors Without Borders and other NGOs if you're interested in relatively short-term assignments. There are a lot of NGOs that you can volunteer with, but many of them expect you to pay your own way.
If you're interested in working on an Indian reservation, look no further than Indian Health Services (
www.ihs.gov), it's a branch of the DHHS. I've looked into it, and as I recall, there are great benefits, but my heart is in Africa.
As far as the scope of practice of practice of nurses in international health, I can tell you that in Africa there is a severe shortage of doctors, so much of the work usually done by MDs is delegated to non-medical personnel. In Ethiopia, nurses are the senior staff of health centers. Nurses diagnose, prescribe, and treat. I was once asked if I wanted to do an LP. I declined, but Ethiopian nurses, with far less training than we have in the U.S., are trained to perform that and other tasks usually performed by MDs in this country.
If you decide to go with a smaller NGO, make sure your job description is well described. I worked for a small NGO and there was a lot of friction between the expatriate MDs and me - they perceived themselves to be my superiors and tried to assign a lot of scut work to me because I was "just a nurse." That wasn't my job, and they thought that what they wanted me to do took precedence over what I had been sent there to do.
I applaud you for wanting to go into international health. I suspect without an MPH you'll probably have to prove yourself by doing volunteer work before you can find a paying gig.
Where do you live? There are some good school of international health in the U.S. I lived in Seattle, but returned to Tulane for the tropical medicine program. Once my wife and I moved here, U.S. New & World Reports rated the University of Washington as one of the best schools of international health in the U.S., with a much higher rating than Tulane! I love New Orleans, and this semester I'm taking the malaria course at Tulane, so I'm glad I'm back.
Good luck, and let me know what you end up doing.