Potential distributions of the parasite Trypanosoma cruzi and its vector Dipetalogaster maxima highlight areas at risk of Chagas disease transmission in Baja California Sur, Mexico, under climate change

Abstract

Dipetalogaster maxima is a primary vector of Chagas disease in the Cape region of Baja California Sur, Mexico. The geographic distribution of D. maxima is limited to this small region of the Baja California Peninsula in Mexico. Our study aimed to construct the ecological niche models (ENMs) of this understudied vector species and the parasite responsible for Chagas disease (Trypanosoma cruzi). We modelled the ecological niches of both species under current and future climate change projections in 2050 using four Representative Concentration Pathways (RCPs): RCP 2.6, RCP 4.5, RCP 6.0, and RCP 8.5. We also assessed the human population at risk of exposure to D. maxima bites, the hypothesis of ecological niche equivalency and similarity between D. maxima and T. cruzi, and finally the abundance centroid hypothesis. The ENM predicted a higher overlap between both species in the Western and Southern coastal regions of the Baja California Peninsula. The climate change scenarios predicted a Northern shift in the ecological niche of both species. Our findings suggested that the highly tourist destination of Los Cabos is a high‐risk zone for Chagas disease circulation. Overall, the study provides valuable data to vector surveillance and control programs.

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].…”

“…Occurrence buffering: an often-used approach consists of determining an optimal buffer area around the occurrences. The radius buffer can be selected in consideration of the dispersal potential of the species [69,81,87,97,101,105,114,117], or after assessing the performance of a series of test models based on buffer with increasing radii (e.g., [100,119]).…”

“…This approach is quite simple, and may prove the most operational [137]. In fact, it has been applied in a number of opportunities to define the accessible area of mosquitoes, kissing bugs and others (i.e., [87,102,117,124,136]).…”