BACKGROUND: The recent geographical expansion of phlebotomine vectors of Leishmania infantum in the Mediterranean subregion has been attributed to ongoing climate changes. At these latitudes, the activity of sand flies is typically seasonal; because seasonal phenomena are also sensitive to general variations in climate, current phenological data sets can provide a baseline for continuing investigations on sand fly population dynamics that may impact on future scenarios of leishmaniasis transmission. With this aim, in 2011-2013 a consortium of partners from eight Mediterranean countries carried out entomological investigations in sites where L. infantum transmission was recently reported. METHODS/PRINCIPAL FINDINGS: A common protocol for sand fly collection included monthly captures by CDC light traps, complemented by sticky traps in most of the sites. Collections were replicated for more than one season in order to reduce the effects of local weather events. In each site, the trapping effort was left unchanged throughout the survey to legitimate inter-seasonal comparisons. Data from 99,000 collected specimens were analyzed, resulting in the description of seasonal dynamics of 56,000 sand flies belonging to L. infantum vector species throughout a wide geographical area, namely P. perniciosus (Portugal, Spain and Italy), P. ariasi (France), P. neglectus (Greece), P. tobbi (Cyprus and Turkey), P. balcanicus and P. kandelakii (Georgia). Time of sand fly appearance/disappearance in collections differed between sites, and seasonal densities showed variations in each site. Significant correlations were found between latitude/mean annual temperature of sites and i) the first month of sand fly appearance, that ranged from early April to the first half of June; ii) the type of density trend, varying from a single peak in July/August to multiple peaks increasing in magnitude from May through September. A 3-modal trend, recorded for P. tobbi in Cyprus, represents a novel finding for a L. infantum vector. Adults ended the activity starting from mid September through November, without significant correlation with latitude/mean annual temperature of sites. The period of potential exposure to L.infantum in the Mediterranean subregion, as inferred by adult densities calculated from 3 years, 37 sites and 6 competent vector species, was associated to a regular bell-shaped density curve having a wide peak center encompassing the July-September period, and falling between early May to late October for more than 99% of values. Apparently no risk for leishmaniasis transmission took place from December through March in the years considered. We found a common pattern of nocturnal females activity, whose density peaked between 11 pm and 2 am. CONCLUSIONS: Despite annual variations, multiple collections performed over consecutive years provided homogeneous patterns of the potential behavior of leishmaniasis vectors in selected sites, which we propose may represent sentinel areas for future monitoring. In the investigated years, higher potential risk for L. infantum transmission in the Mediterranean was identified in the June-October period (97% relative vector density), however such risk was not equally distributed throughout the region, since density waves of adults occurred earlier and were more frequent in southern territories.
- MeSH
- hmyz - vektory parazitologie fyziologie MeSH
- Leishmania infantum fyziologie MeSH
- leishmanióza epidemiologie parazitologie přenos MeSH
- lidé MeSH
- podnebí MeSH
- populační dynamika MeSH
- Psychodidae parazitologie fyziologie MeSH
- roční období MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Středomoří MeSH
BACKGROUND: Phlebotomus perniciosus is the main vector in the western Mediterranean area of the protozoan parasite Leishmania infantum, the causative agent of canine and human visceral leishmaniases. Infected dogs serve as a reservoir of the disease, and therefore measuring the exposure of dogs to sand fly bites is important for estimating the risk of L. infantum transmission. In bitten hosts, sand fly saliva elicits a specific antibody response that reflects the intensity of sand fly exposure. As screening of specific anti-saliva antibodies is limited by the availability of salivary gland homogenates, utilization of recombinant salivary proteins is a promising alternative. In this manuscript we show for the first time the use of recombinant salivary proteins as a functional tool for detecting P. perniciosus bites in dogs. METHODOLOGY/PRINCIPAL FINDINGS: The reactivity of six bacterially-expressed recombinant salivary proteins of P. perniciosus, yellow-related protein rSP03B, apyrases rSP01B and rSP01, antigen 5-related rSP07, ParSP25-like protein rSP08 and D7-related protein rSP04, were tested with sera of mice and dogs experimentally bitten by this sand fly using immunoblots and ELISA. In the immunoblots, both mice and canine sera gave positive reactions with yellow-related protein, both apyrases and ParSP25-like protein. A similar reaction for recombinant salivary proteins was observed by ELISA, with the reactivity of yellow-related protein and apyrases significantly correlated with the antibody response of mice and dogs against the whole salivary gland homogenate. CONCLUSIONS/SIGNIFICANCE: Three recombinant salivary antigens of P. perniciosus, yellow-related protein rSP03B and the apyrases rSP01B and rSP01, were identified as the best candidates for evaluating the exposure of mice and dogs to P. perniciosus bites. Utilization of these proteins, or their combination, would be beneficial for screening canine sera in endemic areas of visceral leishmaniases for vector exposure and for estimating the risk of L. infantum transmission in dogs.
- MeSH
- ELISA MeSH
- hmyzí proteiny diagnostické užití genetika MeSH
- imunoblotting MeSH
- kousnutí a bodnutí hmyzem diagnóza MeSH
- lidé MeSH
- molekulární sekvence - údaje MeSH
- myši MeSH
- Phlebotomus imunologie MeSH
- protilátky krev MeSH
- psi MeSH
- rekombinantní proteiny diagnostické užití genetika MeSH
- sekvenční analýza DNA MeSH
- slinné proteiny a peptidy diagnostické užití genetika MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- myši MeSH
- psi MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
From July 2009 to date, a leishmaniosis outbreak has occurred in the south-west of the Madrid region (Spain) and has already accounted for more than 450 human cases in an area that comprises a population of approximately 500,000. The causative agent is Leishmania infantum and the main vector in the area is Phlebotomus perniciosus. Although canine leishmaniosis prevalence in the focus is not higher than the average in the Madrid region, a wild reservoir - the hare - has been implicated. In this study, we examined the exposure of Leishmania reservoirs in the area: dogs, hares, and wild rabbits to sand fly bites using the detection of specific IgG antibodies against P. perniciosus salivary gland homogenate or recombinant salivary proteins. Hares collected in a green park adjacent to the focus (n=59) showed positive exposure to P. perniciosus bites in comparison to hares from a non-endemic area (Czech Republic, n=18). A significant positive correlation was found between IgG response to yellow protein rSP03B and salivary gland homogenate (r=0.902) and between apyrase rSP01B and salivary gland homogenate (r=0.710). Wild rabbits captured in the study area (n=21) presented higher anti-saliva antibody levels than negative control sera and their IgG response against recombinant salivary proteins were positively correlated with salivary gland homogenate (rSP03B: r=0.710; rSP01B: r=0.666). All sera of dogs from the focus (n=34) showed higher anti-saliva IgG levels than that of non-exposed dogs. Moreover, dogs protected against sand fly bites through the use of topical insecticides and sleeping indoors showed significantly lower antibody levels than the non-protected ones. Antibody response to all three recombinant salivary proteins tested showed positive correlation with salivary gland extract (rSP03B: r=0.858; rSP01: r=0.864; and rSP01B: r=0.861). Data confirmed the exposure of hares, rabbits and dogs to P. perniciosus bites in the context of an outbreak of human leishmaniosis in Spain, highlighting their involvement in Leishmania transmission by supporting their role as potential reservoirs. This novel methodology represents a promising tool for further epidemiological studies that would help to design better strategies for the control of leishmaniosis in this area and other foci.
- MeSH
- imunoglobulin G krev MeSH
- kousnutí a bodnutí hmyzem epidemiologie imunologie veterinární MeSH
- králíci imunologie MeSH
- leishmanióza veterinární MeSH
- Phlebotomus imunologie MeSH
- protilátky krev MeSH
- psi imunologie MeSH
- slinné proteiny a peptidy imunologie MeSH
- zajíci imunologie MeSH
- zvířata MeSH
- Check Tag
- králíci imunologie MeSH
- psi imunologie MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Španělsko MeSH
