Ecology of phlebotomine sand flies and Leishmania infantum infection in a rural area of southern Italy

Epidemiological surveillance of Leishmania infantum in wild lagomorphs in Spanish Mediterranean ecosystems

Wild lagomorphs play a key epidemiological role as reservoirs of Leishmania infantum, causative agent of the largest outbreak of human leishmaniosis in Europe to date. A large-scale survey study was conducted on wild rabbit (Oryctolagus cuniculus) and Iberian hare (Lepus granatensis) populations in Spanish Mediterranean ecosystems to evaluate the exposure of L. infantum and investigate potential risk factors associated with exposure to this zoonotic parasite. Between 2018 and 2021, a total of 631 wild lagomorphs (471 wild rabbits and 160 Iberian hares) were collected in Andalusia (southern Spain) and tested for antibodies against L. infantum using the indirect fluorescent antibody test (IFAT). Spleen samples from 563 of the wild lagomorphs sampled (441 wild rabbits and 122 Iberian hares) were also evaluated by real-time quantitative PCR (qPCR) for detection of Leishmania kDNA. Exposure to L. infantum (positive by IFAT and/or qPCR) was detected in 56.4 % (356/631; 95 %CI: 52.3-60.3) of the lagomorphs analyzed. Anti-Leishmania antibodies were found in 12.8 % (81/631; 95 %CI: 10.2-15.5) of the animals, and L. infantum kDNA was detected in 59.0 % (332/563; 95 %CI: 54.9-63.0) of the spleen samples tested. Phylogenetic analysis revealed high homology (99.9-100 %) between L. infantum sequences obtained and strains previously isolated from humans in Spain. While apparent seroprevalence was significantly higher in Iberian hares (19.4 %; 95 %CI: 13.3-25.5) compared to wild rabbits (10.6 %; 95 %CI: 7.9-13.4), no significant differences in prevalence were found between wild rabbits (61.0 %; 95 %CI: 56.5-65.6) and Iberian hares (51.6 %; 95 %CI: 42.8-60.5). At least one positive animal was found on 64.8 % (70/108) of the hunting grounds sampled, and a high-risk spatial cluster (P < 0.001) was also identified in central Andalusia. The multivariable analysis identified bioclimatic level (meso-Mediterranean climate) and the presence of goats on hunting grounds as risk factors potentially associated with L. infantum exposure in wild lagomorphs. This study shows high, widespread exposure, but heterogeneous distribution of L. infantum in wild lagomorph populations in Mediterranean ecosystems in southern Spain. The results point to the need to promote integrated surveillance programs for the detection of Leishmania spp. in wild lagomorphs in order to establish effective control measures against human leishmaniosis under a One Health approach.

Leishmania spp. in equids and their potential vectors in endemic areas of canine leishmaniasis

Equids may be infected by zoonotic Leishmania spp., including Leishmania infantum, in regions where canine leishmaniasis (CanL) is endemic, and Leishmania martiniquensis, which has been reported in horses from Central Europe. This study was designed to evaluate the occurrence of both Leishmania spp. among equids living in CanL endemic areas of Italy, as well as to identify dipteran vectors from the same habitats. From March to October 2023, blood, serum and tissue samples from skin lesions were collected from equids (n = 98; n = 56 donkeys and n = 42 horses) living in Italy, as well as sand flies and biting midges. Blood samples (n = 98) and skin lesions (n = 56) were tested for Leishmania spp. by conventional and real time PCRs and sera were tested by immunofluorescence antibody tests (IFAT) for both L. infantum and L. martiniquensis. Insects were morphologically identified, and female specimens (n = 268 sand flies, n = 7 biting midges) analyzed for Leishmania DNA, as well as engorged sand flies (n = 16) for blood-meal detection. Two animals with skin lesions (i.e., one donkey and one horse) scored positive for Leishmania spp. DNA, and 19 animals (i.e., 19.4%; n = 13 donkeys and n = 6 horses) were seropositive for L. infantum, with five of them also for L. martiniquensis. Most seropositive animals had no dermatological lesions (i.e., 68.4%) while both animals molecularly positive for Leishmania spp. scored seronegative. Of the 356 sand flies collected, 12 females (i.e., n = 8 Sergentomyia minuta; n = 3 Phlebotomus perniciosus, n = 1 Phlebotomus perfiliewi) were positive for Leishmania spp. DNA, and one out of seven biting midges collected was DNA-positive for L. infantum. Moreover, engorged sand flies scored positive for human and equine DNA. Data suggest that equids living in CanL endemic areas are exposed to Leishmania spp., but their role in the circulation of the parasite needs further investigations.

New paradigms in the prevention of canine vector-borne diseases

The prevention of canine vector-borne diseases (CVBDs) is pivotal for the health and welfare of dogs as well as for reducing their zoonotic risk to humans. Scientific knowledge gained in recent years contributed to the development of new strategies for the control of these diseases in different social and cultural contexts. Here, we discuss recent advances in the prevention of vector-borne pathogens (VBPs) affecting dogs with a focus on those of zoonotic relevance.

ParSCo: celebrating 10 years of a unique parasitology summer course

ParSCo (Parasitology Summer Course) is an intense, 1-week-long summer course organized by the Parasitology Unit of the Department of Veterinary Medicine, University of Bari, Italy, with the support of the World Association for the Advancement of Veterinary Parasitology (WAAVP), the European Veterinary Parasitology College (EVPC) and Parasites and Vectors. The course, which is conducted in southern Italy, is planned for parasitologists and post-graduate students working in the field of parasitology. The course consists of theoretical and practical lessons, which include the collection, identification and diagnosis of parasites of pets, livestock and wildlife. The participants in ParSCo are afforded the opportunity to be involved in clinical examination and sample collection for the diagnosis of parasitic diseases (e.g. leishmaniosis, thelaziosis and many tick-borne diseases) present in the Mediterranean Basin. The course is conducted at Casa di Caccia, a hunting lodge situated in the Gallipoli Cognato Forest near the Basento River in the Basilicata region in southern Italy. In addition to the training purpose, ParSCo is a great opportunity for sharing knowledge and expertise while becoming part of the parasitology community in a pleasant environment. In this editorial, we share some information and celebrate 10 years of ParSCo, looking forward to forthcoming sessions of this unique parasitology summer course.

Reconstructing the post-glacial spread of the sand fly Phlebotomus mascittii Grassi, 1908 (Diptera: Psychodidae) in Europe

Phlebotomine sand flies (Diptera: Phlebotominae) are the principal vectors of Leishmania spp. (Kinetoplastida: Trypanosomatidae). In Central Europe, Phlebotomus mascittii is the predominant species, but largely understudied. To better understand factors driving its current distribution, we infer patterns of genetic diversity by testing for signals of population expansion based on two mitochondrial genes and model current and past climate and habitat suitability for seven post-glacial maximum periods, taking 19 climatic variables into account. Consequently, we elucidate their connections by environmental-geographical network analysis. Most analyzed populations share a main haplotype tracing back to a single glacial maximum refuge area on the Mediterranean coasts of South France, which is supported by network analysis. The rapid range expansion of Ph. mascittii likely started in the early mid-Holocene epoch until today and its spread possibly followed two routes. The first one was through northern France to Germany and then Belgium, and the second across the Ligurian coast through present-day Slovenia to Austria, toward the northern Balkans. Here we present a combined approach to reveal glacial refugia and post-glacial spread of Ph. mascittii and observed discrepancies between the modelled and the current known distribution might reveal yet overlooked populations and potential further spread.

The estimated distribution of autochthonous leishmaniasis by Leishmania infantum in Europe in 2005-2020

BACKGROUND

This study describes the spatial and temporal distribution between 2005 and 2020 of human and animal leishmaniasis by Leishmania infantum in European countries reporting autochthonous cases, and highlights potential activities to improve disease control.

METHODOLOGY/PRINCIPAL FINDINGS

It was based on a review of the scientific literature and data reported by the World Health Organization (WHO), the World Organization for Animal Health (WOAH) and the Ministries of Health, including hospital discharges in some countries. Autochthonous infections were reported in the scientific literature from 22 countries, including 13 and 21 countries reporting human and animal infections, respectively. In contrast, only 17 countries reported autochthonous human leishmaniasis cases to the WHO and 8 countries animal infections to the WOAH. The number of WOAH reported cases were 4,203, comprising 4,183 canine cases and 20 cases in wildlife. Of 8,367 WHO reported human cases, 69% were visceral leishmaniasis cases-of which 94% were autochthonous-and 31% cutaneous leishmaniasis cases-of which 53% were imported and mostly in France. The resulting cumulative incidence per 100,000 population of visceral leishmaniasis between 2005-2020, was highest in Albania (2.15 cases), followed by Montenegro, Malta, Greece, Spain and North Macedonia (0.53-0.42), Italy (0.16), Portugal (0.09) and lower in other endemic countries (0.07-0.002). However, according to hospital discharges, the estimated human leishmaniasis incidence was 0.70 in Italy and visceral leishmaniasis incidences were 0.67 in Spain and 0.41 in Portugal.

CONCLUSIONS/SIGNIFICANCE

Overall, there was no evidence of widespread increased incidence of autochthonous human leishmaniasis by L. infantum in European countries. Visceral leishmaniasis incidence followed a decreasing trend in Albania, Italy and Portugal, and peaked in Greece in 2013, 2014 and 2017, and in Spain in 2006-2007 and 2011-2013. Animal and human cutaneous leishmaniasis remain highly underreported. In humans, hospital discharge databases provide the most accurate information on visceral leishmaniasis and may be a valuable indirect source of information to identify hotspots of animal leishmaniasis. Integrated leishmaniasis surveillance and reporting following the One Health approach, needs to be enhanced in order to improve disease control.

Effects on ectoparasites and nestling body condition of experimental modification of relative humidity in nest cavities of European rollers Coracias garrulus in an arid environment

Climate change effects on host–parasite interactions have been poorly studied in arid or semi-arid habitats. Here, we conducted an experiment aimed to increase the temperature inside European roller Coracias garrulus nest boxes located in a semi-arid habitat on different nest-site types to look for effects on different ectoparasite abundances and nestling growth. Average nest temperature was slightly higher in heated nests than in control nests, although differences were not statistically significant. However, relative humidity was significantly lower at night in heated nests as compared to control nests. The abundance of sand flies, mites and carnid flies was significantly higher in heated, less humid, nests while biting midge abundance was significantly lower in heated nests. Other ectoparasites were not significantly affected by treatment. Relative humidity was high even in heated nests, reaching more than 60%. Sand fly abundance was higher in nests located in sandstone walls, while mite abundance was higher in isolated farmhouses. In addition, sand fly prevalence was higher in nests located in isolated farmhouses and sandstone walls. Heat treatment, nest-site type or ectoparasite abundances did not affect the nestling body mass, wing length or their growth at different nestling ages.

Canine and Feline Parasitology: Analogies, Differences, and Relevance for Human Health

Cats and dogs are treated as family members by most pet owners. Therefore, a high quality of veterinary care and preventive medicine is imperative for animal health and welfare and for the protection of humans from zoonotic pathogens. There is a general perception of cats being treated as "small dogs," especially in the field of clinical parasitology. As a result, several important differences between the two animal species are not taken into proper consideration and are often overlooked. Dogs and cats are profoundly different under evolutionary, biological, ethological, behavioral, and immunological standpoints. These differences impact clinical features, diagnosis, and control of canine and feline parasites and transmission risk for humans. This review outlines the most common parasitoses and vector-borne diseases of dogs and cats, with a focus on major convergences and divergences, and discusses parasites that have (i) evolved based on different preys for dogs and cats, (ii) adapted due to different immunological or behavioral animal profiles, and (iii) developed more similarities than differences in canine and feline infections and associated diseases. Differences, similarities, and peculiarities of canine and feline parasitology are herein reviewed in three macrosections: (i) carnivorism, vegetarianism, anatomy, genetics, and parasites, (ii) evolutionary adaptation of nematodes, including veterinary reconsideration and zoonotic importance, and (iii) behavior and immune system driving ectoparasites and transmitted diseases. Emphasis is given to provide further steps toward a more accurate evaluation of canine and feline parasitology in a changing world in terms of public health relevance and One Health approach.

Canine Leishmaniosis in Greece: An Updated Countrywide Serological Study and Associated Risk Factors

Canine leishmaniosis (Leishmania infantum) is a zoonotic disease that affects dogs worldwide. Greece is enzootic for this disease, and updated data for its current distribution are of major importance. The aim of this cross-sectional serological study was primarily to update the current knowledge of Leishmania infantum seropositivity status within the asymptomatic Greek canine population and, furthermore, to assess the possible climatological and other risk factors. In total, sera of 1265 asymptomatic dogs were collected from all prefectures of the country. A questionnaire that included all individual dog information was completed for all animals. The Speed Leish K^® canine Leishmania antibody test kit (BVT Groupe Virbac, France) was employed. Potential risk factors were evaluated utilizing logistic regression models. Overall, 13.8% (n = 175) of the sampled dogs were seropositive to Leishmania infantum originating from all geographical departments of the country, whereas most prefectures had at least one seropositive animal. Outdoor living, high mean humidity, low mean wind speed and high total annual rainfall were found to increase the seropositivity status against the parasite. Conclusively, Leishmania infantum remains a common parasite challenge in the asymptomatic canine population of Greece, and therefore, its early diagnosis and effective prevention are significant in the country.

Ecology and spatial distribution of sand fly species in low endemic areas for American Tegumentary Leishmaniasis in the municipality of Seropédica, Rio de Janeiro, Brazil

Due to the fundamental role that sand flies (Diptera: Psychodidae) have in Leishmania spp. (Kinetoplastida: Trypanosomatidae) transmission, the objective of this study was to evaluate the ecology and spatial distribution of species circulating in the municipality of Seropédica, Rio de Janeiro, Brazil. A total of 17 371 specimens were collected between August 2016 and July 2017, and five species were identified: Nyssomyia intermedia (Lutz & Neiva, 1912), Migonemyia migonei (França, 1920), Nyssomyia whitmani (Antunes & Coutinho, 1939), Pintomyia pessoai (Coutinho & Barretto, 1940), and Pintomyia fischeri (Pinto, 1926). In relation to the number of sand flies collected, we observed a significant difference between rural and periurban areas and between the neighbourhoods. We observed that N. intermedia has a relatively greater adaptation to the peridomiciliary environment. This is the first report of Pi. pessoai and Pi. fischeri (only females) in Seropédica as well as the first record of the frequency of phlebotomine species focusing on some ecological indices and the spatial distribution of sand flies. The results presented here aimed to provide an insight into the spatial population dynamics of phlebotomine species in low endemic areas of American Tegumentary Leishmaniasis (ATL) in Seropédica, highlighting important areas for entomological surveillance.

Ecology, seasonality and host preferences of Austrian Phlebotomus (Transphlebotomus) mascittii Grassi, 1908, populations

Background

Sand flies are principal vectors of the protozoan parasites Leishmania spp. and are widely distributed in all warmer regions of the world, including the Mediterranean parts of Europe. In Central European countries, the sand fly fauna is still under investigation. Phlebotomus mascittii, a suspected but unproven vector of Leishmania infantum, is regarded as the most widely distributed species in Europe. However, many aspects of its biology and ecology remain poorly known. The aim of this study was to provide new data on the biology and ecology of Ph. mascittii in Austria to better understand its current distribution and potential dispersal.

Methods

Sand flies were collected by CDC light traps at four localities in Austria for 11 (2018) and 15 weeks (2019) during the active sand fly season. Climatic parameters (temperature, relative humidity, barometric pressure and wind speed) were retrospectively obtained for the trapping periods. Sand flies were identified by a combined approach (morphology, DNA barcoding, MALDI-TOF protein profiling), and blood meals of engorged females were analysed by DNA sequencing and MALDI-TOF mass spectrometry.

Results

In total, 450 individuals of Ph. mascittii were caught. Activity was observed to start at the beginning of June and end at the end of August with peaks in mid-July at three locations and early August at one location. Increased activity was associated with relatively high temperatures and humidity. Also, more individuals were caught on nights with low barometric pressure. Analysis of five identified blood meals revealed chicken (Gallus gallus) and equine (Equus spp.) hosts. Sand fly abundance was generally associated with availability of hosts.

Conclusion

This study reports unexpectedly high numbers of Ph. mascittii at selected Austrian localities and provides the first detailed analysis of its ecology to date. Temperature and humidity were shown to be good predictors for sand fly activity. Blood meal analyses support the assumption that Ph. mascittii feeds on mammals as well as birds. The study significantly contributes to understanding the ecology of this sand fly species in Central Europe and facilitates prospective entomological surveys.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-021-04787-2.

Species diversity and blood meal sources of phlebotomine sand flies (Diptera: Psychodidae) from Los Tuxtlas, Veracruz, Mexico

Phlebotomine sand flies can transmit several species of the genus Leishmania, that cause leishmaniasis, a serious neglected tropical disease worldwide. Although Mexico is an endemic country for the disease, studies on the biology, ecology, and the identification of blood meal sources of phlebotomine sand flies in some states remain unexplored. For this reason, this study aimed to evaluate the species diversity of sand flies, and identify their blood meal sources in the Biosphere Reserve Los Tuxtlas, Veracruz, an area with a high prevalence of Leishmania infantum. The cumulative sampling effort of sand flies covered 300 trap-nights between March 2011 and May 2013. For estimating species diversity, we calculated the species richness (q = 0), the diversity of the species (q = 1) and the dominant species (q = 2). To identify the blood meal sources, we amplified and sequenced a fragment of ≈400 bp of the vertebrate Cytb gene. A total of 951 specimens belonging to 15 species were collected. Psathyromyia aclydifera and Psychodopygus panamensis were the most abundant species. We were able to identify seven terrestrial vertebrate species, among which human beings were the most common source of the blood meal. In this study, relevant information on the structure of sand fly populations and their blood meal sources was obtained, providing basic and important information about the interactions between sand flies, hosts and Leishmania species.

Occurrence of Phlebotomine sand flies (Diptera: Psychodidae) in the northeastern plain of Italy

BACKGROUND

Recent climate and environmental changes have resulted in the geographical expansion of Mediterranean Leishmania infantum vectors towards northern latitudes and higher altitudes in different European countries, including Italy, where new foci of canine leishmaniasis have been observed in the northern part of the country. Northern Italy is also an endemic area for mosquito-borne diseases. During entomological surveillance for West Nile virus, mosquitoes and other hematophagous insects were collected, including Phlebotomine sand flies. In this study, we report the results of Phlebotomine sand fly identification during the entomological surveillance conducted from 2017 to 2019.

METHODS

The northeastern plain of Italy was divided by a grid with a length of 15 km, and a CO2-CDC trap was placed in each geographical unit. The traps were placed ~ 15 km apart. For each sampling site, geographical coordinates were recorded. The traps were operated every two weeks, from May to November. Sand flies collected by CO2-CDC traps were identified by morphological and molecular analysis.

RESULTS

From 2017 to 2019, a total of 303 sand flies belonging to the species Phlebotomus perniciosus (n = 273), Sergentomyia minuta (n = 5), P. mascittii (n = 2) and P. perfiliewi (n = 2) were collected, along with 21 unidentified specimens. The trend for P. perniciosus collected during the entomological surveillance showed two peaks, one in July and a smaller one in September. Sand flies were collected at different altitudes, from -2 m above sea level (a.s.l.) to 145 m a.s.l. No correlation was observed between altitude and sand fly abundance.

CONCLUSIONS

Four Phlebotomine sand fly species are reported for the first time from the northeastern plain of Italy. Except for S. minuta, the sand fly species are competent vectors of Leishmania parasites and other arboviruses in the Mediterranean Basin. These findings demonstrate the ability of sand flies to colonize new environments previously considered unsuitable for these insects. Even though the density of the Phlebotomine sand fly population in the plain areas is consistently lower than that observed in hilly and low mountainous areas, the presence of these vectors could herald the onset of epidemic outbreaks of leishmaniasis and other arthropod-borne diseases in areas previously considered non-endemic.

Integrative Approach to Phlebotomus mascittii Grassi, 1908: First Record in Vienna with New Morphological and Molecular Insights

Sand flies (Diptera: Psychodidae: Phlebotominae) are blood-feeding insects that transmit the protozoan parasites Leishmania spp. and various arthropod-borne (arbo) viruses. While in Mediterranean parts of Europe the sand fly fauna is diverse, in Central European countries including Austria mainly Phlebotomus mascittii is found, an assumed but unproven vector of Leishmania infantum. To update the currently understudied sand fly distribution in Austria, a sand fly survey was performed and other entomological catches were screened for sand flies. Seven new trapping locations of Ph. mascittii are reported including the first record in Vienna, representing also one of the first findings of this species in a city. Morphological identification, supported by fluorescence microscopy, was confirmed by two molecular approaches, including sequencing and matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) protein profiling. Sand fly occurrence and activity were evaluated based on surveyed locations, habitat requirements and climatic parameters. Moreover, a first comparison of European Ph. mascittii populations was made by two marker genes, cytochrome c oxidase subunit 1 (COI), and cytochrome b (cytb), as well as MALDI-TOF mass spectra. Our study provides new important records of Ph. mascittii in Austria and valuable data for prospective entomological surveys. MALDI-TOF MS protein profiling was shown to be a reliable tool for differentiation between sand fly species. Rising temperatures and globalization demand for regular entomological surveys to monitor changes in species distribution and composition. This is also important with respect to the possible vector competence of Ph. mascittii.

Molecular detection of Leishmania (Sauroleishmania) tarentolae in human blood and Leishmania (Leishmania) infantum in Sergentomyia minuta: unexpected host-parasite contacts

The detection of atypical Kinetoplastida in vertebrate hosts and vectors might suggest unexpected host-parasite contacts. Aside to major vectors of Leishmania (Leishmania) infantum in Italy (e.g. Phlebotomus perniciosus and Phlebotomus perfiliewi), the sand fly fauna also includes Sergentomyia minuta, herpetophilic and proven vector of Leishmania (Sauroleishmania) tarentolae, in which records of blood meal on mammals and detection of L. infantum DNA are increasing. This study was conducted in Central Italy aiming to molecularly detect potential atypical Leishmania host-vector contacts. Detection of Leishmania spp. DNA was performed by polymerase chain reaction (SSU rRNA, ITS1 targets) on field-collected sand fly females (N = 344), blood samples from humans (N = 185) and dogs (N = 125). Blood meal identification was also performed on engorged sand flies. Leishmania spp. DNA was found in 13.1% sand flies, 3.7% humans and 14.4% dogs. Sequence analysis identified L. infantum in S. minuta (4.4%), P. perniciosus (9.1%), humans (2.2%) and dogs (14.4%). Leishmania tarentolae was detected in S. minuta (12.6%), P. perfiliewi (6.6%) and human (1.6%) samples. Of 28 S. minuta examined for blood meal, 3.6 and 21.4% scored positive for human and lizard DNA, respectively. These results indicate the importance of one-health approach to explore new potential routes of transmission of leishmaniasis involving S. minuta.

Ecology of sand flies (Diptera: Psychodidae, Phlebotominae) in a new focus of leishmaniasis in northern Iran

Leishmaniasis is an important infectious disease in Iran. Rudbar County of Guilan Province is introduced as a new focus of cutaneous leishmaniasis. The present study is going to investigate the sand flies fauna in the province and their seasonality and ecology in Rudbar County. To study the sand flies fauna, the sampling was carried out in ten localities of Guilan Province using light traps, sticky traps and manual aspirators during 2016. For the determination of seasonality, the sampling was carried out every two weeks in the fixed site of Pareh Village of Rudbar County during April-October 2016. Sand Flies were removed from sticky traps, rinsed in acetone and then conserved in 80% ethanol as well as the samples of light traps and hand catch. In total, 4430 specimens of sand flies of the genera Phlebotomus and Sergentomyia were collected and identified including Ph. kandelakii, Ph. neglectus, Ph. perfiliewi, Ph. sergenti, Ph. tobbi and Se. dentata. Sergentomyia dentata was found for the first time in Guilan Province. The most prevalent species were Ph. tobbi (55.87%), Ph. perfiliewi (36.03%) and Ph. kandelakii (6. 97%). The seasonality of sand flies started in late May and ended in middle October in the fixed site. The peak of activity of Ph. kandelakii was in late June; however that was in late August for Ph. perfiliewi and Ph. tobbi. The monthly abundance of total sand flies was positively correlated with saturation deficit (P = 0.043). The abundance of Ph. perfiliewi was positively correlated with maximum temperature (P = 0.016), relative humidity (P = 0.006), rainfall (P = 0.007), saturation deficit (P = 0.003) and negatively with minimum temperature (P = 0.005). The abundance of Ph. tobbi was positively correlated with saturation deficit (P = 0.041) and negatively with minimum temperature (P = 0.043). The presence of suspected vectors of cutaneous and visceral leishmaniasis, Ph. kandelakii, Ph. neglectus, Ph. perfiliewi, Ph. sergenti and Ph. tobbi, is noteworthy. Finding the exact vectors of leishmaniasis using specific tests in the province is suggested.

Molecular detection and identification of Leishmania DNA and blood meal analysis in Phlebotomus (Larroussius) species

BACKGROUND

Phlebotomus (Larroussius) perniciosus and Canis familiaris are respectively the only confirmed vector and reservoir for the transmission of Leishmania (L.) infantum MON-1 in Tunisia. However, the vector and reservoir hosts of the two other zymodemes, MON-24 and MON-80, are still unknown. The aim of this study was to analyze the L. infantum life cycle in a Tunisian leishmaniasis focus. For this purpose, we have focused on: i) the detection, quantification and identification of Leishmania among this sand fly population, and ii) the analysis of the blood meal preferences of Larroussius (Lar.) subgenus sand flies to identify the potential reservoirs.

METHODOLOGY AND FINDINGS

A total of 3,831 sand flies were collected in seven locations from the center of Tunisia affected by human visceral leishmaniasis. The collected sand flies belonged to two genus Phlebotomus (Ph.) (five species) and Sergentomyia (four species). From the collected 1,029 Lar. subgenus female sand flies, 8.26% was positive to Leishmania by ITS1 nested PCR. Three Leishmania spp. were identified: L. infantum 28% (24/85), L. killicki 13% (11/85), and L. major 22% (19/85). To identify the blood meal sources in Ph. Lar. subgenus sand flies, engorged females were analyzed by PCR-sequencing targeting the vertebrate cytochrome b gene. Among the 177 analyzed blood-fed females, 169 samples were positive. Sequencing results showed seven blood sources: cattle, human, sheep, chicken, goat, donkey, and turkey. In addition, mixed blood meals were detected in twelve cases. Leishmania DNA was found in 21 engorged females, with a wide range of blood meal sources: cattle, chicken, goat, chicken/cattle, chicken/sheep, chicken/turkey and human/cattle. The parasite load was quantified in fed and unfed infected sand flies using a real time PCR targeting kinetoplast DNA. The average parasite load was 1,174 parasites/reaction and 90 parasites/reaction in unfed and fed flies, respectively.

CONCLUSION

Our results support the role of Ph. longicuspis, Ph. perfiliewi, and Ph. perniciosus in L. infantum transmission. Furthermore, these species could be involved in L. major and L. killicki life cycles. The combination of the parasite detection and the blood meal analysis in this study highlights the incrimination of the identified vertebrate in Leishmania transmission. In addition, we quantify for the first time the parasite load in naturally infected sand flies caught in Tunisia. These findings are relevant for a better understanding of L. infantum transmission cycle in the country. Further investigations and control measures are needed to manage L. infantum transmission and its spreading.

Species diversity and molecular insights into phlebotomine sand flies in Sardinia (Italy)-an endemic region for leishmaniasis

This study provides updated information on the distribution of the phlebotomine sand fly species and their genetic characterization in Sardinia, a Mediterranean island where leishmaniasis is endemic. From April to November 2017, sand flies were trapped in five different capture sites using sticky traps and light traps as collection methods, operated nearby sheep, poultry, cat, and dog shelters. Phlebotomine specimens (n = 513) collected were morphologically and molecularly identified as Phlebotomus perniciosus (249/513, 48.5%), Phlebotomus perfiliewi (236/513; 46%), and Sergentomyia minuta (28/513, 5.5%). Sand flies were collected from the second half of May to October confirming the well-defined seasonal activity, which peaks in August in Sardinia. Overall, correlation analyses indicated a significant positive association between the monthly number of sand flies collected and the mean temperature (r = 0.88, rho = 0.87, and tau = 0.69, P < 0.05), while there was non-significant, moderately negative correlation between the monthly number of sand flies collected and the monthly mean relative humidity and wind (r = - 0.22, rho = 0.02, and tau = 0.04, P > 0.05). This study provides the first data on the molecular characterization of phlebotomine sand flies in this region and confirms the presence of three sand fly species. Molecular results suggest that the morphological features used for analysis represent synapomorphic-derived characters which are shared among descendant taxa and the common ancestor.

Seroprevalence of canine Leishmania infantum infection in the Mediterranean region and identification of risk factors: The example of North-Eastern and Pyrenean areas of Spain

The Mediterranean basin is an endemic region for canine leishmaniosis (CanL), where it represents a major veterinary problem and raises human health concerns. However, the distribution of the disease is heterogeneous and not all countries and locations have been equally studied and characterized. This work describes the situation of CanL in Girona province (Catalonia, Spain), for which no data has been previously reported, and presents a relevant study to exemplify other areas with similar characteristics across the region. Four cross-sectional seroprevalence surveys were performed from 2012 to 2016 throughout the province, including 36 sampling stations in 26 localities and a total of 593 dogs. For each animal, individual and location variables were also collected. Additionally, each dog owner answered a questionnaire about their knowledge of CanL and preventive methods used. Blood samples were analysed by an in-house ELISA and a mixed logistic regression model was used to assess the relationship between pre-determined variables and dog seropositivity. A Spearman's correlation was used to assess the association between dog owners' perceived risk of CanL and Leishmania infantum seropositivity in dogs at a given location. The overall true seroprevalence estimated for Girona province was 19.5% (95%CI: 15.5-23.5), of which only 6.8% (10/146) were considered symptomatic. Age of the dog [OR = 1.21 (95%CI: 1.11-1.31); p < 0.001] and altitude [OR = 0.02 (95%CI: 0.001-0.19); p = 0.001] were identified as risk factors for the infection. The results obtained in this study are expected to aid in the implementation of directed control programmes in CanL endemic areas throughout Europe, as well as to provide suitable data for the design of better risk assessment maps of the disease.

Do Different LED Colours Influence Sand Fly Collection by Light Trap in the Mediterranean?

Light traps represent the most used attractive system to collect and monitor phlebotomine sand flies. Recent studies have suggested that light traps can be easily upgraded by the use of light-emitting diode (LED) with positive effects on trap design, weight, and battery life. However, scant data on the effect of different LED colours on the attractiveness to phlebotomine sand fly species are available in literature. In this study, the capture performances of light traps equipped with different LED colours on phlebotomine sand fly species indigenous in the Mediterranean area were evaluated. Phlebotomine sand fly collections were performed using a classical light trap (CLT), equipped with a traditional incandescent lamp, and five Laika 4.0 light traps supplied, each with LED of different colours and wavelengths: (i) white; (ii) red; (iii) green; (iv) blue; (v) UV. Light traps were set for three consecutive nights fortnightly from May to October 2017 and climate data recorded using a meteorological station. A total of 411 phlebotomine sand flies (191 males and 220 females), belonging to three different species, namely, Phlebotomus perniciosus (n= 298, 141 males and 157 females), Sergentomyia minuta (n=110, 48 males and 62 females), and Phlebotomus neglectus (n=3, 2 males and 1 females) were collected. Abundance of capture was influenced by colours of LED and time. The highest number of phlebotomine sand flies was captured on June (P<0.01) and by UV LED (P<0.01). As regard to species, P. perniciosus was mainly captured by UV LED on June (P<0.01). No effect of time (P>0.05) or LED colour (P>0.05) was recorded for S. minuta and P. neglectus. According to the results of the present study light trap equipped with UV LED can represent an effective tool for the capture of sand fly species in the Mediterranean area.

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

The spatial and temporal distribution of Phlebotomus perniciosus (Diptera: Psychodidae) (Newstead, 1911), the sand fly vector of pathogens of public and animal health importance, was investigated in a high sand fly density rural area in Spain using light-attraction and sticky-interception traps. Traps were placed inside animal buildings and outside at increasing distance from animals. A total of 8506 sand flies were collected, 87% with light traps. Species frequency differed between trap types. The abundance of P. perniciosus decreased exponentially with increasing distance to animals and, while females were most common in the animal enclosure, males predominated in adjoining storage places. Increasing CO₂ concentration had an additional positive effect on female abundance only. Both male and female density increased with rising temperature, and there was some indication that females were more active than males at higher relative humidity. The study confirms that P. perniciosus aggregates around animal premises, although male and female distributions differ and should be analysed separately to account for biological and behavioural differences. This provides further evidence that light traps offer an accurate estimation of the relative spatial and temporal abundance of P. perniciosus, conferring an added value for the study of this species and the risk of pathogen transmission.

Gold nanoparticles - against parasites and insect vectors

Nanomaterials are currently considered for many biological, biomedical and environmental purposes, due to their outstanding physical and chemical properties. The synthesis of gold nanoparticles (Au NPs) is of high interest for research in parasitology and entomology, since these nanomaterials showed promising applications, ranging from detection techniques to drug development, against a rather wide range of parasites of public health relevance, as well as on insect vectors. Here, I reviewed current knowledge about the bioactivity of Au NPs on selected insect species of public health relevance, including major mosquito vectors, such as Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus. The toxicity of Au NPs against helminths was reviewed, covering Schistosoma mansoni trematodes as well as Raillietina cestodes. Furthermore, I summarized the information available on the antiparasitic role of Au NPs in the fight against malaria, leishmaniosis, toxoplasmosis, trypanosomiasis, cryptosporidiosis, and microsporidian parasites affecting human and animals health. Besides, I examined the employ of Au NPs as biomarkers, tools for diagnostics and adjuvants for the induction of transmission blocking immunity in malaria vaccine research. In the final section, major challenges and future outlooks for further research are discussed, with special reference to the pressing need of further knowledge about the effect of Au NPs on other arthropod vectors, such as ticks, tsetse flies, tabanids, sandflies and blackflies, and related ecotoxicology assays.

Neglected vector-borne zoonoses in Europe: Into the wild

Wild vertebrates are involved in the transmission cycles of numerous pathogens. Additionally, they can affect the abundance of arthropod vectors. Urbanization, landscape and climate changes, and the adaptation of vectors and wildlife to human habitats represent complex and evolving scenarios, which affect the interface of vector, wildlife and human populations, frequently with a consequent increase in zoonotic risk. While considerable attention has focused on these interrelations with regard to certain major vector-borne pathogens such as Borrelia burgdorferi s.l. and tick-borne encephalitis virus, information regarding many other zoonotic pathogens is more dispersed. In this review, we discuss the possible role of wildlife in the maintenance and spread of some of these neglected zoonoses in Europe. We present case studies on the role of rodents in the cycles of Bartonella spp., of wild ungulates in the cycle of Babesia spp., and of various wildlife species in the life cycle of Leishmania infantum, Anaplasma phagocytophilum and Rickettsia spp. These examples highlight the usefulness of surveillance strategies focused on neglected zoonotic agents in wildlife as a source of valuable information for health professionals, nature managers and (local) decision-makers. These benefits could be further enhanced by increased collaboration between researchers and stakeholders across Europe and a more harmonised and coordinated approach for data collection.

Field evaluation of a new light trap for phlebotomine sand flies

Light traps are one of the most common attractive method for the collection of nocturnal insects. Although light traps are generally referred to as "CDC light traps", different models, equipped with incandescent or UV lamps, have been developed. A new light trap, named Laika trap 3.0, equipped with LED lamps and featured with a light and handy design, has been recently proposed into the market. In this study we tested and compared the capture performances of this new trap with those of a classical light trap model under field conditions. From May to November 2013, a Laika trap and a classical light trap were placed biweekly in an area endemic for sand flies. A total of 256 sand fly specimens, belonging to 3 species (Sergentomyia minuta, Phlebotomus perniciosus, Phlebotomus neglectus) were collected during the study period. The Laika trap captured 126 phlebotomine sand flies: P. perniciosus (n=38); S. minuta (n=88), a similar number of specimens (130) and the same species were captured by classical light trap which collected also 3 specimens of P. neglectus. No significant differences in the capture efficiency at each day of trapping, neither in the number of species or in the sex of sand flies were observed. According to results of this study, the Laika trap may be a valid alternative to classical light trap models especially when handy design and low power consumption are key factors in field studies.

Detection of high Leishmania infantum loads in Phlebotomus perniciosus captured in the leishmaniasis focus of southwestern Madrid region (Spain) by real time PCR

Since 2010 a human leishmaniasis outbreak has been notified in southwestern Madrid region that still remains active. Entomological surveys have been carried out in the affected area in order to obtain information about species diversity, distribution, and density of sand flies. Moreover, molecular identification of blood meal preferences of sand flies and molecular detection of Leishmania infantum has been performed. In this work, we optimized a real time PCR assay in order to determine parasite loads in unfed and blood-fed Phlebotomus perniciosus female sand flies caught in the focus area. Results showed elevated parasite loads in nearly 70% of the studied positive sand flies. Furthermore, significantly higher parasite loads were observed in females without blood in their guts. In conclusion, high L. infantum loads found in P. perniciosus sand flies from the Madrid focus support the exceptional characteristics of this outbreak.

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

Background

Leishmaniosis 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.

Methods

Twenty-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.

Results

The 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.

Conclusions

A 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 material

The online version of this article (doi:10.1186/s13071-017-2135-3) contains supplementary material, which is available to authorized users.

Species of sand flies (Diptera: Psychodidae) collected from natural reserves in the Pacific and Darien regions of Colombia

INTRODUCTION

The departments of Chocó and Antioquia in Colombia show climatic and vegetation conditions favoring the establishment of vector species of the genus Lutzomyia and the transmission of Leishmania spp. to human populations entering conserved forest environments.

OBJECTIVE

To report the species of Phlebotomine sandflies present in three natural reserves in the Darien and Pacific regions of Colombia.

MATERIALS AND METHODS

Sand flies were collected specifically in the natural reserves El Aguacate (Acandí, Chocó), Nabugá (Bahía Solano, Chocó) and Tulenapa (Carepa, Antioquia). Sand flies were collected with CDC light traps, active search in resting places and Shannon traps. The taxonomic determination of species was based on taxonomic keys. For some species of taxonomic interest, we evaluated the partial sequences of the 5' region of COI gene.

RESULTS

A total of 611 adult sand flies were collected: 531 in Acandí, 45 in Carepa and 35 in Bahía Solano. Seventeen species of the genus Lutzomyia, three of the genus Brumptomyia and one of the genus Warileya were identified. The genetic distances (K2P) and grouping supported (>99%) in the neighbor joining dendrogram were consistent for most established molecular operational taxonomic units (MOTU) of the Aragaoi group and clearly confirmed the identity of Lu. coutinhoi.

CONCLUSION

Species that have importance in the transmission of leishmaniasis in Acandí, Bahía Solano and Carepa were identified. The presence of Lu. coutinhoi was confirmed and consolidated in Colombia.

Changes of Sand Fly Populations and Leishmania infantum Infection Rates in an Irrigated Village Located in Arid Central Tunisia

The current spread of zoonotic visceral leishmaniasis (ZVL) throughout arid areas of Central Tunisia is a major public health concern. The main objective of this study is to investigate whether the development of irrigation in arid bio-geographical areas in Central Tunisia have led to the establishment of a stable cycle involving sand flies of the subgenus Larroussius and Leishmania infantum, and subsequently to the emergence of ZVL. Sand flies were collected from the village of Saddaguia, a highly irrigated zone located within an arid bio-geographical area of Central Tunisia by using modified Centers for Diseases Control (CDC) light traps. Morphological keys were used to identify sand flies. Collected sand flies were pooled with up to 30 specimens per pool according to date and tested by nested Polymerase Chain Reaction (PCR) DNA sequencing from positive pools was used to identify Leishmania spp. A total of 4915 sand flies (2422 females and 2493 males) were collected from Saddaguia in September and in October 2014. Morphological identification confirmed sand flies of the subgenus Larroussius to be predominant. PCR analysis followed by DNA sequencing indicated that 15 pools were infected with L. infantum yielding an overall infection rate of 0.6%. The majority of the infected pools were of sand fly species belonging to subgenus Larroussius. Intense irrigation applied to the arid bio-geographical areas in Central Tunisia is at the origin of the development of an environment capable of sustaining important populations of sand flies of the subgenus Larroussius. This has led to the establishment of stable transmission cycles of L. infantum and subsequently to the emergence of ZVL.

Identification of Algerian Field-Caught Phlebotomine Sand Fly Vectors by MALDI-TOF MS

BACKGROUND

Phlebotomine sand flies are known to transmit Leishmania parasites, bacteria and viruses that affect humans and animals in many countries worldwide. Precise sand fly identification is essential to prevent phlebotomine-borne diseases. Over the past two decades, progress in matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has emerged as an accurate tool for arthropod identification. The objective of the present study was to investigate the usefulness of MALDI-TOF MS as a tool for identifying field-caught phlebotomine.

METHODOLOGY/PRINCIPAL FINDINGS

Sand flies were captured in four sites in north Algeria. A subset was morphologically and genetically identified. Six species were found in these areas and a total of 28 stored frozen specimens were used for the creation of the reference spectrum database. The relevance of this original method for sand fly identification was validated by two successive blind tests including the morphological identification of 80 new specimens which were stored at -80°C, and 292 unknown specimens, including engorged specimens, which were preserved under different conditions. Intra-species reproducibility and inter-species specificity of the protein profiles were obtained, allowing us to distinguish specimens at the gender level. Querying of the sand fly database using the MS spectra from the blind test groups revealed concordant results between morphological and MALDI-TOF MS identification. However, MS identification results were less efficient for specimens which were engorged or stored in alcohol. Identification of 362 phlebotomine sand flies, captured at four Algerian sites, by MALDI-TOF MS, revealed that the subgenus Larroussius was predominant at all the study sites, except for in M'sila where P. (Phlebotomus) papatasi was the only sand fly species detected.

CONCLUSION

The present study highlights the application of MALDI-TOF MS for monitoring sand fly fauna captured in the field. The low cost, reliability and rapidity of MALDI-TOF MS analyses opens up new ways in the management of phlebotomine sand fly-borne diseases.

Ecology of sand flies in a low-density residential rural area, with mixed forest/agricultural exploitation, in north-eastern Brazil

Cutaneous leishmaniasis caused by Leishmania braziliensis is endemic in Brazil, where Lutzomyia whitmani is the most important vector involved in the transmission to humans, particularly in the peridomestic environment. Herein, we assessed the ecology of sand flies, including Lu. whitmani, in a low-density residential rural area with mixed forest/agricultural exploitation in north-eastern Brazil, where cutaneous leishmaniasis is endemic. Particularly, we hypothesized that sand fly abundance was correlated with climatic variables. Sand fly collections were carried out monthly from August 2013 to August 2014, using seven CDC light traps, for three consecutive nights, in three kinds of environments: indoor, peridomicile and forest. Collected sand flies were identified based on morphology and females of Lu. whitmani (n=169), Lu. amazonensis (n=134) and Lu. complexa (n=21) were selected and tested by PCR for Leishmania (Viannia) spp. In total, 5167 sand flies belonging to 19 species were identified, being that Lu. choti (43.2%) was the most frequent species, followed by Lu. amazonensis (16.6%), Lu. whitmani (15.8%), Lu. sordellii (10.7%) and Lu. quinquefer (5.8%), which together represented over 90% of the collected sand flies. All females tested by PCR were negative. The number of sand flies collected daily was positively correlated with temperature and negatively correlated with rainfall and relative humidity. Furthermore, there was a positive correlation between daily number of sand flies and daily average saturation deficit. This study points out that the number of sand flies captured daily is correlated to climatic variables, including saturation deficit, which may represent a useful parameter for monitoring sand fly populations in leishmaniasis-endemic areas.

Leishmaniosis of companion animals in Europe: an update

Leishmaniosis caused by Leishmania infantum is a vector-borne zoonotic disease endemic in southern Europe, but which is spreading northwards. Millions of dogs, cats and other non-conventional companion animals susceptible to L. infantum, living in European households, may develop a severe disease and contribute to the spread of leishmaniosis because of travelling or re-homing. Dogs are the main reservoir but other new reservoirs have recently been incriminated. Sand flies remain the sole proven vector and non-vectorial transmission has been reported at individual level and in areas where the vector is absent. Clinical disease affects only a proportion of infected dogs and a complex genetic background of immune response is responsible for this susceptibility. There is a wide range of serological and parasitological diagnostic tools available whose cost-effective use depends on a reasoned approach. Clinical response to treatment of sick dogs is variable. Clinical cure is often obtained but clinical recurrence can occur and post-therapy follow up should be maintained life-long. In Europe, vaccination can be combined with individual protection with pyrethroids as part of an integrated approach to prevention. L. infantum is the only species isolated from cats in Europe and xenodiagnosis substantiated that infected cats are infectious for sand flies. Feline infection may be frequent in endemic areas, but prevalence is generally lower than in dogs. When cats are tested by both serological and molecular techniques discordant results are often observed. Feline cases have been reported from endemic areas in Italy, France, Spain and Portugal, but four cases were also diagnosed in Switzerland in cats that had travelled to or been imported from Spain. Half of the cases were diagnosed in cats with impaired immune responses. Clinical manifestations compatible with feline leishmaniosis include lymph node enlargement, skin and mucocutaneous lesions, ocular lesions, chronic gingivostomatitis, hypergammaglobulinemia, and normocytic normochromic anemia. Cats have been empirically treated with some drugs used in dogs. Due to polymorphic clinical picture and the insidious progressive course, leishmaniosis can persist for a long time before dogs or cats are brought to a veterinarian and so diagnosis can be delayed. Exotic or new Leishmania spp. have been reported in humans, animals and vectors in Europe. This changing situation requires attention in Europe for designing epidemiological studies and control measures.

Morphological keys for the identification of Italian phlebotomine sand flies (Diptera: Psychodidae: Phlebotominae)

Background

Phlebotomine sand flies are small blood-feeding insects of great medical and veterinary significance. Their identification relies basically on the microscopic examination of key morphological characters. Therefore, identification keys are fundamental to any researcher dealing with these insects. The Italian fauna of phlebotomine sand flies consists of eight species (Phlebotomus perniciosus, Phlebotomus perfiliewi, Phlebotomus ariasi, Phlebotomus neglectus, Phlebotomus papatasi, Phlebotomus mascittii, Phlebotomus sergenti and Sergentomyia minuta), whose morphological delineation may be troublesome for non-taxonomists.

Methods

A total of 8,757 pictures were taken from the 419 selected phlebotomine sand fly specimens collected on different occasions. Twenty-eight characters for the males and 23 for the females were examined, resulting in a database containing over 10,000 entries. Representative phlebotomine sand fly specimens for each species available were selected and relevant characters were drawn with the aid of a camera lucida.

Results

After detailed morphological study of representative specimens, comprehensive identification keys based on key characters (e.g., pharynx and spermathecae of females and male terminalia) were elaborated.

Conclusions

The identification keys provided herein allow the identification of genera and species of phlebotomine sand flies of Italy and they will facilitate future studies on these medically important insects.