Why is Nipah confined to a small pocket of Kerala?

Concept: Nipah, a deadly viral disease is confined only to a small pocket of Kerala. While various pathological investigations have been carried out, an understanding of the micro-climatic, geomorphic, ecological and hydrological contributors that facilitate the habitat for the bats that carry the virus in the area is not well studied. Understanding and mapping these factors in the Nipah pocket of Kerala may help in regionally mapping out potential risk zones for such bat borne diseases. Data: 1) Incidence location inventory; 2) Fairly high-quality geodatabase of the State with DEM, geomorphology, hydrology, landuse etc Need field work: Yes