Assessment of Climate-Driven Variations in Malaria Transmission in Senegal Using the VECTRI Model

Abstract

Several vector-borne diseases, such as malaria, are sensitive to climate and weather conditions. When unusual conditions prevail, for example, during periods of heavy rainfall, mosquito populations can multiply and trigger epidemics. This study, which consists of better understanding the link between malaria transmission and climate factors at a national level, aims to validate the VECTRI model (VECtor borne disease community model of ICTP, TRIeste) in Senegal. The VECTRI model is a grid-distributed dynamical model that couples a biological model for the vector and parasite life cycles to a simple compartmental Susceptible-Exposed-Infectious-Recovered (SEIR) representation of the disease progression in the human host. In this study, a VECTRI model driven by reanalysis data (ERA-5) was used to simulate malaria parameters, such as the entomological inoculation rate (EIR) in Senegal. Observed malaria data from the National Malaria Control Program in Senegal (PNLP/Programme National de Lutte contre le Paludisme au Senegal) and outputs from the climate data used in this study were compared. The findings highlight the unimodal shape of temporal malaria occurrence, and the seasonal malaria transmission contrast is closely linked to the latitudinal variation of the rainfall, showing a south–north gradient over Senegal. This study showed that the peak of malaria takes place from September to October, with a lag of about one month from the peak of rainfall in Senegal. There is an agreement between observations and simulations about decreasing malaria cases on time. These results indicate that the southern area of Senegal is at the highest risk of malaria spread outbreaks. The findings in the paper are expected to guide community-based early-warning systems and adaptation strategies in Senegal, which will feed into the national malaria prevention, response, and care strategies adapted to the needs of local communities.

Impact of seasonal malaria chemoprevention timing on clinical malaria incidence dynamics in the Kedougou region, Senegal

“…Furthermore, in this study, the week of the year was used to adjust for seasonal changes in malaria risk. In other studies, these seasonal changes can be modeled using meteorological parameters, such as rainfall, temperature, and/or composite indicators, and their effect on incidence can be quantified (16,21).…”

“…Malaria incidence was expressed as the number of cases per 1000 population per week. Based on this descriptive analysis and a previous study assessing climate-driven variations in malaria transmission in Senegal (16), the years were divided into 2 transmission periods: low transmission period and high transmission period. Incidence was calculated for 5-year age groups for individuals <20 years, using age-group and village - specific denominators, including both 0-4 and 5-9 eligible for SMC and 10-14 and 15-19 uneligible for SMC.…”

Verification of operational numerical weather prediction model forecasts of precipitation using satellite rainfall estimates over Africa

“…NOAA RFE2 and ARC2 were selected in part as comparison datasets due to their common use by end‐users across weather risk management (Osgood & Shirley, 2012), disease modelling (Mbouna et al, 2019; Fall et al, 2022; Kim et al, 2019; Ngwa et al, 2016; Ssentongo et al, 2018) and Personalized Predictive Health (Agamile & Lawson, 2021), who might also have interest in the ability of forecasts to ‘sync’ with these estimates. The choice also allows the results of this work to be directly compared with several other forecast validation efforts over Africa.…”

The Impact of Climate Change on Malaria Incidence in Bonaberi and Tombel Districts, Cameroon

“…Globally, due to malaria 241 million cases and 627 000 deaths were recorded in 2020 with a percentage of 7.8 deaths [7]. There is an increase from an estimated 227 million cases and 558 000 deaths recorded in 2019.…”

“…Malaria may be in uenced by future climate change depending on the distribution of infected female Anopheles mosquitoes, competent to transmit Plasmodium falciparum [5]. The biting rates, development and mortality of anopheles vectors are in uenced by temperature [7]. The breeding ground that favors larval development is enhanced by rainfall [8].…”