Importance of individual analysis of environmental and climatic factors affecting the density of Leishmania vectors living in the same geographical area: the example of Phlebotomus ariasi and P. perniciosus in northeast Spain

Abstract

Abstract. The aim of the present study was to determine the role of specific environmental and climatic factors affecting the distribution and density of Phlebotomus ariasi and P. perniciosus, the proven vectors for Leishmania infantum in Spain. An entomological study was carried out in July 2006 in the province of Lleida with sticky traps set in their diurnal resting places at altitudes ranging from 86 to 1,755 m above the mean sea level (339 sites were sampled). Bivariate analysis revealed that factors such as altitude, bioclimatic zone, temperature, precipitation, sampling site (site relative to settlement, site situation, site category), wall vegetation, particular environment (in this case a natural park), general environment, adjacent natural vegetation and land cover were significantly associated with sand fly densities. The multivariate model for P. perniciosus revealed that its density was affected by site and land cover. Specifically, paved driveways correlated negatively with vector density (Incidence Risk Ratio (IRR): 0.41) and arable land cover correlated positively (IRR: 4.59). In the case of P. ariasi, a significant correlation was observed with the altitude and bioclimatic zone, with density increasing at >800 m above the mean sea level (IRR: 3.40) and decreasing in the meso-Mediterranean bioclimatic zone (IRR: 0.08). Both species were mostly found in agricultural and forest areas far from domestic environments. However, the two species correlated differently with altitude, bio-climate, vegetation, temperature and precipitation, which emphasises the importance of their individual analysis in studies regarding risk of leishmaniasis transmission.

Temperature effects on the activity of vectors forLeishmania tropicaalong rocky habitat gradients in the Eastern Mediterranean

“…The seasonal pattern and differences among the four sites are explained by temperature variation over the year and along the elevation gradient. Our results show an exponential relationship between ambient temperature and sand fly activity, in contrast to previous studies which revealed only general correlations between temperature and sand fly abundance (Ballart et al 2014, Figure 3. The estimated activity of sand flies by Julian date along selected sites in the eastern Galilee region.…”

Ecology and spatiotemporal dynamics of sandflies in the Mediterranean Languedoc region (Roquedur area, Gard, France)

“…ariasi was collected at almost all altitudes with a peak of abundance in mid-slope areas. Its highest densities were recorded between 400 and 500 m of altitude, although this species can be found >800 m above sea level and also in subalpine and mountain climates [9, 31]. Se.…”

“…Similar findings were reported for Ph. ariasi in Spain [31]. This species can be found in a variety of habitats and usually prefers relatively high temperatures with moderate relative humidity.…”

Factors influencing the presence of sand flies in Majorca (Balearic Islands, Spain) with special reference to Phlebotomus pernicious, vector of Leishmania infantum

“…In July 2008 sand fly captures were carried out in Majorca with sticky castor oil interception traps (20×20 cm) set for 4 days according to the standardized methodology implemented in the EDEN project (EU) [ 18 – 21 ]. The sampling sites consisted of holes used to drain embankments or containment walls, which were considered to be likely diurnal resting places for adult sand flies [ 22 ].…”