"The disease is more common in temperate and tropical geographical areas and usually the disease is said to be found in Africa, Middle East and West Asia. But, from recent times, almost all American states have got affected and from time to time there are outbreaks of large number of patients with West Nile Disease."
Useful little review on the how/why/what of WNV. Including the fact that we Africans have been living with it forever...B-)