There have been several outbreaks in the interim period, just like we are faced with now. The reasons for its outbreak now are several. Increased urbanization, changing climate, deforestation and many other ecological factors are responsible for the spread. Also, shortage of resources for bat populations compelled bats to move from their natural habitats to agricultural areas added with human intervention into the bat infested areas due to rapid urbanization. Moreover, mismanagement of large piggeries is also a cause of the spread of NiV.