Unraveling Malaria Transmission Dynamics in Saudi Arabia using Climate Sensitive VECTRI model

Malaria is one of the deadliest tropical diseases, which is transmitted to human through the bite of Anopheles mosquitos infected with the Plasmodium parasite. The incidence of malaria infections has been increasing globally over recent decades. However, the incidences of confirmed malaria cases in the Kingdom of Saudi Arabia (KSA) have declined significantly. In this study, we assessed the spatio-temporal distribution of malaria across KSA, investigating its relationship with climate change. We used the malaria model VECTRI to simulate malaria incidences from 1981 to 2017 (37 years), forced with high-resolution regional climate variables. The model outputs were validated against available data. Malaria parameters such as, vector density (VD) (herein mosquito density) and entomological inoculation rate (EIR) were simulated, based on which six high-risk malaria provinces in KSA were identified. Malaria vector abundance and malaria transmission rates were higher between April to June and underwent an increasing trend over the Asir, Jizan, Najran, Al-Bahah, Makkah, and Medina provinces relative to other regions. We also found that the simulated optimal mean temperature and rainfall for malaria transmission were between 29 to 34 °C and 0.4 to 1.0 mm/day, respectively. VECTRI simulations show that malaria parasite was most abundant one month after the identified optimal rainfall and temperature. Our results are important for policymakers in KSA to identify the region’s most prone to malaria and to prepare adequate response and mitigation strategies.