Potential distribution of dominant malaria vector species in tropical region under climate change scenarios

Abstract

Risk assessment regarding the distribution of malaria vectors and environmental variables underpinning their distribution under changing climates is crucial towards malaria control and eradication. On this basis, we used Maximum Entropy (MaxEnt) Model to estimate the potential future distribution of major transmitters of malaria in Nigeria— Anopheles gambiae sensu lato and its siblings: Anopheles gambiae sensu stricto, and Anopheles arabiensis under low and high emissions scenarios. In the model, we used mosquito occurrence data sampled from 1900 to 2010 alongside land use and terrain variables, and bioclimatic variables for baseline climate 1960–1990 and future climates of 2050s (2041–2060) and 2070s (2061–2080) that follow RCP2.6 and RCP8.5 scenarios. The Anopheles gambiae species are projected to experience large shift in potential range and population with increased distribution density, higher under high emissions scenario (RCP8.5) and 2070s than low emission scenario (RCP2.6) and 2050s. Anopheles gambiae sensu stricto and Anopheles arabiensis are projected to have highest invasion with 47–70% and 10–14% percentage increase, respectively in Sahel and Sudan savannas within northern states in 2041–2080 under RCP8.5. Highest prevalence is predicted for Humid forest and Derived savanna in southern and North Central states in 2041–2080; 91–96% and 97–99% for Anopheles gambiae sensu stricto, and 67–71% and 72–75% for Anopheles arabiensis under RCP2.6 and RCP8.5, respectively. The higher magnitude of change in species prevalence predicted for the later part of the 21st century under high emission scenario, driven mainly by increasing and fluctuating temperature, alongside longer seasonal tropical rainfall accompanied by drier phases and inherent influence of rapid land use change, may lead to more significant increase in malaria burden when compared with other periods and scenarios during the century; especially in Humid forest, Derived savanna, Sahel and Sudan savannas.

Present and future climatic suitability for dengue fever in Africa

“…aegypti in relation to dengue fever incidence will increase in the future in Africa, which is in agreement with other studies [4,7,8,19].WHO also stated that the endemicity of dengue fever incidence will increase, and outbreak could occur in areas where they are currently unknown due to climate changes [36]. Changes in temperature have been predicted to determine mosquito-borne disease occurrence, primarily through changes in mosquito reproduction, development and survival, and pathogen incubation rates and survival [2,6,14,17,37,38]. Our study identified that temperature is the most important climatic variable, which collectively determined 70.8% of the potential distribution of Ae.…”

Vegetation Response to Recent Trends in Climate and Landuse Dynamics in a Typical Humid and Dry Tropical Region under Global Change

“…is finding is consistent with studies that show that in arid and semiarid areas, moisture availability is a primary modulator of vegetation growth [48,51,53,54,63].…”

“…e average precipitation declined sharply in 2004 and increased again from 2004 to 2012, after which it decreased again with significant fluctuations during this period ( Figure 5(d)). e highest annual precipitation occurred in 2012 for the entire study period which also coincided with extensive nationwide flooding Advances in Meteorology and spread of epidemics in some cases [61][62][63]. Generally, rainfall exhibited positive trend in about 18.36% of total vegetated areas, out of which only about 0.47% was significant ( Figures 6(b) and 6(d)).…”

“…Our findings, however, agrees with studies that [18,19] reported slight but significant decline in vegetation vigour. In areas where rainfall is positively correlated with NDVI and both rainfall and NDVI trend declined overtime, this kind of relationship suggests a climate-induced desertification in arid areas [63,64,65]. Long-term precipitation analysis for the area revealed decreasing trend in annual rainfall amounts, and the 1968 to 2008 mean rainfall was reported to have shifted downwards by 8.8 percent from the long-term mean [52,54].…”

Evaluating the Effects of Climate and Environmental Factors on Under-5 Children Malaria Spatial Distribution Using Generalized Additive Models (GAMs)

“…However, among the sub-Saharan African countries, Nigeria has the highest share of the global burden of malaria disease [3]. More than 95% of the malaria cases in Nigeria are caused by P. falciparum [10][11][12], mostly occurring in children under the age of 5 years [3,10,12]. At present almost more than 70% of the Nigerian population live in endemic areas [13,14].…”