Existence of vector-borne disease in desert type climate

Abstract:

Vector-borne diseases are primarily influenced by changes in climatic systems. Temperature and Precipitation are basic climate parameters linked closely to the geographical distribution of prominent vector and parasite species. The existence of vector-borne diseases in tropical regions is obvious due to the presence of sufficient moisture along with optimum temperature which favours larval development. Yet, the presence of vector-borne disease in the desert climatology is a matter of research, when the optimum temperature for their survival is around 27 ºC. However, limited numerical modeling studies have been carried out to investigate the relationship between vector-borne disease and climatic factors, especially in desert type climate. Therefore, a study is performed using a dynamical model (VECTRI), to simulate a vector-borne disease i.e. malaria for the period of 1981-2004. The input is a multimodel mean of 21 Coupled Model Intercomparison Project Phase 5 (CMIP5) historical models data, which was downscaled by NASA as Earth Exchange Global Daily Downscaled Projections (NEX-GDDP). The spatiotemporal changes (region-specific as well as seasonal changes) in the malaria transmission as a result of climatic changes are quantified over the Arabian region. The VECTRI model simulated parameters such as larvae density (LD), vector density (VD), and entomological inoculation rate (EIR) identified vector-borne disease transmission hotspots such as the southwestern strip of Arabian shield and Yemeni Highlands. In the desert region, the optimum mean temperature for malaria transmission was between 29 to 34 ºC, which is much higher than normal. Similarly, precipitation was much below normal around 1.0 mm/day. It was observed that the malaria transmission had a lag of one month after the identified optimal rainfall and temperature occurred in the region.