Let me clarify one thing. There is no fixed time period during which you have to start treatment, but obviously sooner is better. The time frame depends on where you were bitten and how serious it is. A massive attack to the head is a crisis. A small nip on the foot, not as much of an emergency. The virus has to travel to the brain before you show symptoms. The closer the bite is to the brain and the more virus that is injected, the worse the situation is.
Preventive rabies vaccination is called "pre-exposure vaccination." It is a series of three shots given over a month.
Rabies vaccination does not make you truly immune--not like, say, measles shots. What it does do is buy you time to get treatment and reduce the treatment regime. If you get the pre-exposure vaccination, then the after-bite treatment is two shots of vaccine, three days apart.
IIf you were not previously vaccinated, then you need a shot of rabies immune globulin AND a series of five rabies vaccinations, given over the course of a month (not all at once). The immune globulin may be expensive and/or very hard to find. (I've seen report where people had to pay $US1,000). Sometimes vaccine has not been stored properly and is not fully effective.
The immune globulin should be given within 7 days of the exposure. You can start the vaccine immediately & then head for some place where you can get the immune globulin.
There is a branch of the Institute Pasteur in Antananarivo. They have a rabies treatment clinic. So the issue would be--can you easily get there?
Some people choose to put the money they would have spent for immunization into really good medical evacuation insurance--that would not only get you to some place where you can be treated, but would organize all the logistics for you.