As India marks an important milestone in its fight against polio, international health experts say that it is too soon to declare victory. Mass vaccination has eradicated the crippling disease in many parts of the world. But polio transmission and sudden outbreaks remain a challenge in large regions of the Indian subcontinent, including Pakistan and Afghanistan, as well as in west and central Africa. VOA's Vidushi Sinha has more on the epidemic that just won't quit.]]
