Ecological niche modeling for predicting the potential geographical distribution of Aedes species (Diptera: Culicidae): A case study of Enugu State, Nigeria

Abstract

Arbovirus transmission by Aedes mosquitoes has long been a significant problem in Africa. In West Africa, Aedes vector management faces significant challenges; lack of recent Aedes distributional data and potential distributional modeling hinder effective vector control and pose serious public health issues. In this study, larval and adult mosquitoes were collected from four study sites in Enugu State, Nigeria every other month between November 2017 and September 2018. A total number of 2997 Aedes mosquitoes were collected and identified, and 59 positive field occurrence points for both Aedes adult and larvae were recorded. A total of 18 positive occurrence points were used for modeling. Ecological Niche Models (ENMs) were used to estimate the current geographic distribution of Aedes species ( spp. ) in Enugu State, south-east Nigeria, and mosquito presence was used as a proxy for predicting risk of disease transmission. Maximum Entropy distribution modeling or “MaxEnt” was used for predicting the potential suitable habitats, using a portion of the occurrence records. A total of 23 environmental variables (19 bioclimatic and four topographic) were used to model the potential geographical distribution area under current climatic conditions. The most suitable habitat for Aedes spp. was predicted in the northern, central, and southeastern parts of Enugu State with some extensions in Anambra, Delta, and Edo States in the west, and Ebonyi State in the east. Seasonal temperature, precipitation of the wettest month, mean monthly temperature range, elevation, and precipitation of the driest months were the highest estimated main variable contributions associated with the distribution of Aedes spp. We found that Aedes spp. prefer to be situated in environmental conditions where precipitation of wettest month ranged from 265 to 330 mm, precipitation of driest quarter ranged from 25 to 75 mm while precipitation of wettest quarter ranged from 650 to 950 mm. Aedes mosquitoes, such as Ae. aegypti and Ae. albopictus, pose a significant threat to human health, hence, the results of this study will help decision makers to monitor the distribution of these species and establish a management plan for future national mosquito surveillance and control programs in Nigeria.

Current Risk of Dirofilariosis Transmission in the Iberian Peninsula (Spain and Portugal) and the Balearic Islands (Spain) and Its Future Projection under Climate Change Scenarios

“…Among the measures that can be considered to control this disease, as with other diseases that are also mediated by vectors of transmission, is the prediction of the dispersal capacity of these agents through ecological niche modeling (ENM) processes. As a biological species, they are assumed to respond to environmental factors, of which bioclimatic characteristics are the most important [31,32]. Determining where the most favorable circumstances for their existence are found can be a major advance in the best ability to deal with them preventively.…”

Ecological Niche Modelling Approaches: Challenges and Applications in Vector-Borne Diseases

“…Thus, whenever possible, the databases to be used must be filtered and reinforced with a molecular identification (i.e., [69,[80][81][82]). Despite the aforementioned, the issue is usually neglected, and most of the studies rely solely on morphological identification (e.g., [83][84][85][86][87][88][89][90][91][92][93][94][95][96], but see [97] for a mixed approach), or do not even describe the identification method [70,82,[98][99][100][101][102][103][104][105][106][107][108].…”

“…As far as we know, this is what occurs with a large amount of the studies dealing with VBDs. As these kinds of studies are usually performed with public health purposes at regional or local scales, they often rely on regional/national datasets collected by administrations or NGOs whose range of action is defined by restricted geographical or political borders (i.e., country or even provinces' administrations) (e.g., [67][68][69]80,[83][84][85][86][87][88][89][90][91][92][93][94][95][96]98,99,101,[104][105][106][107][108][112][113][114][115][116][117]). The concern resides in the fact that ENM built with occurrence data restricted to artificial boundaries might consider only a subset of the environmental conditions experienced by a species across its entire range (i.e., "spatial niche truncation" [118]); therefore, providing an incomplete description of the environmental limits [109] and underestimating the environmental conditions that the species can withstand [111] (see an example in Figure 2).…”

“…However, if many occurrence records are available, geographical filtering and balancing of occurrence data should be preferred relative to background manipulation [145]. Indeed, this method seems to be by far the most frequently used (e.g., [69,70,81,83,87,92,93,97,100,103,[105][106][107]112,116,117,119]). However, if only few spatially clustered occurrence records are available, the manipulation of the background dataset seems to be the second-best option [145].…”

Diversity analysis, distribution and abundance of mosquito assemblages Diptera: Culicidae at urban sector from southwestern Colombia.

“…There are studies focused on the analysis of the richness, abundance and distribution of this family in tropical areas, where climate and its variations are key to understanding its biology and the possible health implications in a context of environmental crisis (Boyer et The Culicidae family have been studied worldwide. In Africa, the geographic distribution of the species of the genus Aedes were studied (Omar et al 2021). Speci cally, Guarido et al (2021) studied in South Africa, Aedes and Culex genera which were recognized as transmitters of the VBDs.…”