Indian Ocean Basin-Wide (IOBW) Index:
According to a study, Indian Ocean basin-wide (IOBW) index exhibits a close association with dengue outbreaks in both the Northern and Southern hemispheres.
- Indian Ocean basin-wide (IOBW) Index represents the average sea-surface temperature variations across the tropical Indian Ocean.
- It has emerged as a key indicator for predicting the magnitude and timing of dengue epidemics in each country.
- Its association with the Southern Hemisphere is stronger than that with the Northern Hemisphere.
- It has a more pronounced impact on temperatures in tropical regions. Brazil, for example, bears a higher burden of dengue in the Southern Hemisphere.
- The Northern Hemisphere witnesses a peak dengue epidemic period between July and October and the Southern Hemisphere in February and April, both in the summers.
- Further, the amplitude of dengue incidence was high when the index was positive and low when it was negative.
- The link between the Indian Ocean’s temperature and dengue incidence is likely due to its influence on regional temperatures through teleconnections, large-scale atmospheric patterns that can transfer heat and moisture across vast distances.
