Understanding Phlebotomus perniciosus abundance in south-east Spain: assessing the role of environmental and anthropic factors

Abstract

BackgroundLeishmaniosis is associated with Phlebotomus sand fly vector density, but our knowledge of the environmental framework that regulates highly overdispersed vector abundance distributions is limited. We used a standardized sampling procedure in the bioclimatically diverse Murcia Region in Spain and multilevel regression models for count data to estimate P. perniciosus abundance in relation to environmental and anthropic factors.MethodsTwenty-five dog and sheep premises were sampled for sand flies using adhesive and light-attraction traps, from late May to early October 2015. Temperature, relative humidity and other animal- and premise-related data recorded on site and other environmental data were extracted from digital databases using a geographical information system. The relationship between sand fly abundance and explanatory variables was analysed using binomial regression models.ResultsThe total number of sand flies captured, mostly with light-attraction traps, was 3,644 specimens, including 80% P. perniciosus, the main L. infantum vector in Spain. Abundance varied between and within zones and was positively associated with increasing altitude from 0 to 900 m above sea level, except from 500 to 700 m where it was low. Populations peaked in July and especially during a 3-day heat wave when relative humidity and wind speed plummeted. Regression models indicated that climate and not land use or soil characteristics have the greatest impact on this species density on a large geographical scale. In contrast, micro-environmental factors such as animal building characteristics and husbandry practices affect sand fly population size on a smaller scale.ConclusionsA standardised sampling procedure and statistical analysis for highly overdispersed distributions allow reliable estimation of P. perniciosus abundance and identification of environmental drivers. While climatic variables have the greatest impact at macro-environmental scale, anthropic factors may be determinant at a micro-geographical scale. These finding may be used to elaborate predictive distribution maps useful for vector and pathogen control programs.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-017-2135-3) contains supplementary material, which is available to authorized users.

Investigations of Phlebotomus perniciosus sand flies in rural Spain reveal strongly aggregated and gender‐specific spatial distributions and advocate use of light‐attraction traps

“…These conditions were met on several occasions during the study when vector abundance differed substantially. In the previous 2015 Murcia regional study, vector abundance correlated better with T and RH (Risueño et al., ). Such differences are to be expected when comparing abundances in areas that are far apart and have substantially different climatic conditions.…”

“…Differences between studies could also be related to the sampling strategy, which was more intensive in the present study and covered a wider geographical area in Risueño et al . ().…”

“…Sand flies approach hosts in a series of short flight hops, and walls or other surfaces facilitate this behaviour. Light traps were placed close to vertical surfaces and abundance was negatively related to wall distance in the bivariate analysis, as reported before (Risueño et al., ). Moonlight reduces the distance from which light traps are visible (Alexander, ).…”

“…This may also explain the absence of a negative association between wind speed and sand fly abundance. In contrast, strong prevailing winds were considered an important factor limiting sand fly abundance on a large geographical scale in Murcia Region (Risueño et al., ).…”

Effect of trapping method on species identification of phlebotomine sandflies by MALDI‐TOF MS protein profiling

“…This is the first study to use MALDI‐TOF MS protein profiling in field specimens caught by two different trapping methods in order to evaluate the effects of trap type on the quality of protein spectra and thus their potential for successful species identification. Specimens included in this study were collected in different habitats at seven periurban or agricultural sites in southeast Spain, where sandfly species composition, spatial distribution and ecological traits have been intensively studied (Muñoz et al ., , Risueño et al ., ). Specimens of different sandfly species acquired by light traps produced protein profiles of quality sufficient to provide a high rate of successful identification and only three could not be unequivocally identified (Table ).…”