What do you think happens to people who live in remote parts of the jungle in countries like Africa or Brazil, and there’s no one to tell them about Islam, or any other religion. What does God or Allah think about them?
The claim of Islam is not that man is born morally and spiritually blind, and God’s message comes to show him the light. Its claim is that man has already been given good nature and intuitive knowledge of God and afterlife when he is sent to this world. Prophets came to remind him of something that was already there – God-given knowledge – and also add to it to let man know much more.The principle on which the accountability of the hereafter would take place is that humans will have to be answerable on the basis of what they could know and what they could possibly do. They will not be questioned for what they had no possibility of knowing and doing. On the basis of what has been mentioned above, the people living in the remote parts of the jungles of Africa and Brazil will not be asked about anything that they didn’t know. They would most certainly be held accountable for their attitude towards God, His blessings, and the moral guidance they were born with.
Courtesy: http://www.islamicissues.info/qa_question.php?qid=265