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Green periurban residential areas in Mediterranean countries have flourished in the last decades and become foci for leishmaniasis. To remedy the absence of information on vector ecology in these environments, we examined phlebotomine sand fly distribution in 29 sites in Murcia City over a 3-year period, including the plots of 20 detached houses and nine non-urbanized sites nearby. We collected 5,066 specimens from five species using “sticky” interception and light attraction traps. The relative frequency of the main Leishmania infantum vector Phlebotomus perniciosus in these traps was 32% and 63%, respectively. Sand fly density was widely variable spatially and temporally and greatest in non-urbanized sites, particularly in caves and abandoned buildings close to domestic animal holdings. Phlebotomus perniciosus density in house plots was positively correlated with those in non-urbanized sites, greatest in larger properties with extensive vegetation and non-permanently lived, but not associated to dog presence or a history of canine leishmaniasis. Within house plots, sand fly density was highest in traps closest to walls. Furthermore, the study provides a guideline for insect density assessment and reporting and is envisioned as a building block towards the development of a pan-European database for robust investigation of environmental determinants of sand fly distribution.

An epidemiological study was carried out to investigate asymptomatic Leishmania infantum infection by PCR and ELISA in wild rabbits, humans and domestic dogs in southeastern Spain. Seroprevalence was 0% (0/36) in rabbits, 2% (13/657) in humans and 7% (14/208) in dogs. The prevalence of PCR-positives was 0.6% (1/162) in rabbits tested in a wide range of tissue samples, 2% (8/392) in humans analysed in blood samples and 10% (20/193) and 67% (29/43) in dogs analysed in blood and lymphoid tissue samples, respectively. Results suggest that wild rabbits have a very low risk of becoming chronically infected with L. infantum, and provide further evidence that cryptic L. infantum infection is widespread in the domestic dog population and is also present in a comparatively smaller proportion of healthy humans. The epidemiological and clinical implications of these findings are discussed.

The relationship between Canine Leishmaniosis (CanL) seroprevalence and regular use of topical insecticides was investigated in 800 pet dogs with no visible signs of CanL in Murcia, southeast Spain in 2011. Dogs were clients to 17 veterinary practices and were analyzed for Leishmania infantum antibodies in blood plasma using two commercial ELISAs (Ingezim, Ingenasa®, Spain; Leishcan, Hipra®, Spain). Owners were interviewed to gather data on dog related variables. They included date of birth, home address and frequency, duration and timing of insecticide treatments used to prevent ectoparasite infestations. The dog's residence was georeferenced and environmental data potentially associated with the dog's risk of L. infantum infection was obtained. A mixed logistic regression model was then developed to analyze the relationship between the dog's serological status and insecticidal treatment adjusted for demographic and environmental variables. Overall, CanL seroprevalence (95% confidence limits) was 18% (16-21%) including 11% in dogs not using insecticide treatments (n=60) and 19% in those using them (n=740) (p>0.05). At least 16 different insecticide products were used and 73%, 26% and 1% of dogs received 1, 2 and 3 products a year. The most frequent commercial brands used and the only ones in the market claiming anti-sandfly activity, were Scalibor collars (deltametrin 40mg/g; MSD®), Advantix pipettes (permethrin 500mg/ml and imidacloprid 100mg/ml; Bayer®) and Exspot spot-on pipettes (permethrin 715mg/ml; MSD®). Seroprevalence was 9%, 16%, 20%, 22% and 25% for dogs with Scalibor collars plus Advantix pipettes, Scalibor collars plus ExSpot pipettes, Advantix pipettes alone, Scalibor collars alone and Exspot pipettes alone, respectively. The multivariable model confirmed a significant reduction in the risk of Leishmania spp. seropositivity in dogs using the Scalibor and Advantix combination compared to those using either product alone and provided evidence of greatly increased risk of CanL in rural areas situated at 300-500m altitude and average March-July temperatures of 18.6-19°C. The study highlights the difficulty in controlling CanL infection by means of insecticide use alone and that it could be improved by using the Scalibor and Advantix combination and identifying and targeting specific geographical areas.