Geographical distribution of Culicoides (DIPTERA: CERATOPOGONIDAE) in mainland Portugal: Presence/absence modelling of vector and potential vector species

Abstract

Vector-borne diseases are not only accounted responsible for their burden on human health-care systems, but also known to cause economic constraints to livestock and animal production. Animals are affected directly by the transmitted pathogens and indirectly when animal movement is restricted. Distribution of such diseases depends on climatic and social factors, namely, environmental changes, globalization, trade and unplanned urbanization. Culicoides biting midges are responsible for the transmission of several pathogenic agents with relevant economic impact. Due to a fragmentary knowledge of their ecology, occurrence is difficult to predict consequently, limiting the control of these arthropod vectors. In order to understand the distribution of Culicoides species, in mainland Portugal, data collected during the National Entomologic Surveillance Program for Bluetongue disease (2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013), were used for statistical evaluation. Logistic regression analysis was preformed and prediction maps (per season) were obtained for vector and potentially vector species. The variables used at the present study were selected from WorldClim (two climatic variables) and CORINE databases (twenty-two land cover variables). This work points to an opposite distribution of C. imicola and species from the Obsoletus group within mainland Portugal. Such findings are evidenced in autumn, with the former appearing in Central and Southern regions. Although appearing northwards, on summer and autumn, C. newsteadi reveals a similar distribution to C. imicola. The species C. punctatus appears in all Portuguese territory throughout the year. Contrary, C. pulicaris is poorly caught in all areas of mainland Portugal, being paradoxical present near coastal areas and higher altitude regions.

Monthly variation in the probability of presence of adult Culicoides populations in nine European countries and the implications for targeted surveillance

“…In our maps, C. imicola appeared to be present all year round, as it can be found on the southern coast of Spain during January and February. This agrees with previous analyses of the start of the vector season in Europe, where C. imicola was found to be present during the winter months in southern Spain and central and southern Portugal [ 65 ]. The predicted probability of presence shown in our maps are in agreement to the distribution models made for Spain by Ducheyne et al [ 56 ], Calvete et al [ 55 ] and Peters et al [ 70 ], and for France, where the Presence areas for the species are mainly located in the coastal regions of Corsica and VAR department [ 15 ].…”

Environmental Drivers of Adult Seasonality and Abundance of Biting Midges Culicoides (Diptera: Ceratopogonidae), Bluetongue Vector Species in Spain

“…In addition, prior studies established a direct relationship between Culicoides abundance measured in traps and the probability of Bluetongue virus occurrences (Calvete et al 2008, Guis et al 2012. In agreement with the literature summarized in Table 1, C. imicola is highly abundant in south-western regions of Spain during summer; has longer adult activity seasons and prefers higher temperatures, probably related with its Afrotropical preferences (Ortega et al 1999;Miranda et al 2004Miranda et al , 2007Talavera et al 2015;Ramilo et al 2017). Its peaks of adult activity occur between 16 and 18°C, and the species is absent in sites with cold winters Mellor 1994, Venter et al 2019).…”

A model for the assessment of bluetongue virus serotype 1 persistence in Spain

“…Breeding site preferences of Pulicaris complex are ill-defined and likely flexible [81]. Our finding that altitude is quite important for Pulicaris occurrence is consistent with previous work [37,71], although few studies have examined this complex on the Iberian Peninsula [37,74]. Our results suggest that altitude should be taken into account when modeling Pulicaris complex distribution.…”

“…We did not require an indication of the direction of variables' importance because many studies using parametric techniques have identified factors that drive Culicoides spp. ecology and have described how those factors interact with Culicoides distribution or abundance [22,23,26,[69][70][71][72][73][74]. Although RF tolerates variable collinearity, some studies have shown that correlated variables can be favored in the process of growing trees [75].…”