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