Moslem religious leaders in northern Nigeria continue to  urge their followers not to let their children take polio vaccine. Because of this, polio has killed or crippled hundreds of children in the last year, and the disease, which was on the verge of being wiped out (like smallpox was in the 1970s), is spreading to neighboring countries. Years of anti-Christian, and especially anti-American Moslem propaganda has resulted in a widely believed fear that the vaccine actually makes the female children sterile and is part of a plot to kill off all Africans. Some of the Moslem religious leaders have admitted that this is absurd, but it is what many northern Nigerians believe and few religious leaders are willing to preach against it. The government organized tests of the vaccine to disprove the accusations. But some Moslem leaders refuse to believe any test results that contradict their beliefs. 

Much of the anger up north is really all about money and power. For decades, northern men ran the national government, and funneled much of the stolen oil wealth up north. But the current government, an anti-corruption one, is largely southerners. While the corruption is still there, all that cash flowing north is not there any more. That money is missed.