Species composition, activity patterns and blood meal analysis of sand fly populations (Diptera: Psychodidae) in the metropolitan region of Thessaloniki, an endemic focus of canine leishmaniasis

Sand Fly larvae are capable of positive chemotaxis: a proof of concept study using Phlebotomus papatasi (Diptera: Psychodidae) as a model species

Phlebotomine sand flies are important vectors of medical and veterinary importance, transmitting pathogens, such as the Leishmania parasites, responsible for 700,000 to 1 million new cases of leishmaniasis every year. The vast majority of the current sand fly surveillance and control tools are tailored against the adult stages, due to the limited knowledge on the ecology of the larval stages. Since vector control is primarily an ecological problem, an in-depth understanding of the behavior of the target insect pests across all the different life stages of their development is required prior to the development of effective control strategies. It is well known that chemical cues play an important role in insect behavior. While there are numerous studies investigating the behavior of adult sand flies in response to chemical sources, there is currently no information available on the response of their larval stages. In this study, novel bioassays were constructed to investigate the effect of chemical cues (gustatory and olfactory) on the behavior of Phlebotomus papatasi (Scopoli) sand fly larvae. The larvae exhibited a clear food preference within a few hours of exposure in a 2-choice bioassay, while, also, demonstrated positive chemotaxis in response to volatile stimuli emitted from their preferred food source. Identification of the specific chemical compounds (or the combination thereof) eliciting attractance response to sand fly immature stages could lead to the development of innovative, and targeted (larval-specific) tools for the surveillance, and management of these important public health pests.

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.

Leishmaniosis in Greece: The Veterinary Perspective

Leishmaniosis caused by the protozoon Leishmania infantum that is transmitted through the bites of infected phlebotomine sandflies is of major veterinary concern in Greece. The country is endemic with particularly favourable environmental conditions for the spread of this infection. Moreover, Greece remains a popular touristic destination, and the continuous travel of pets raises concern regarding the possible dissemination of infection from endemic to non-endemic areas. Dogs are the main reservoir host, although other animal species, including humans, may also be infected. Canine leishmaniosis manifests as a visceral disease that can result in death if left untreated. Serological and molecular epizootiological studies have confirmed circulation of the parasite in Greek canine and feline populations as well as in other mammals. As a result, constant surveillance and identification of high-risk localities are necessary to establish chemoprophylactic protocols for travelling animals to safeguard animal and public health.

Molecular taxonomy of phlebotomine sand flies (Diptera, Psychodidae) with emphasis on DNA barcoding: A review

The taxonomy and systematics of sand flies (Diptera, Psychodidae, Phlebotominae) are one of the pillars of research aimed to identifying vector populations and the agents transmitted by these insects. Traditionally, the use of morphological traits has been the main line of evidence for the definition of species, but the use of DNA sequences is useful as an integrative approach for their delimitation. Here, we discuss the current status of the molecular taxonomy of sand flies, including their most sequenced molecular markers and the main results. Only about 37% of all sand fly species have been processed for any molecular marker and are publicly available in the NCBI GenBank or BOLD Systems databases. The genera Phlebotomus, Nyssomyia, Psathyromyia and Psychodopygus are well-sampled, accounting for more than 56% of their sequenced species. However, less than 34% of the species of Sergentomyia, Lutzomyia, Trichopygomyia and Trichophoromyia have been sampled, representing a major gap in the knowledge of these groups. The most sequenced molecular markers are those within mtDNA, especially the DNA barcoding fragment of the cytochrome c oxidase subunit I (coi) gene, which has shown promising results in detecting cryptic diversity within species. Few sequences of conserved genes have been generated, which hampers higher-level phylogenetic inferences. We argue that sand fly species should be sequenced for at least the coi DNA barcoding marker, but multiple markers with different mutation rates should be assessed, whenever possible, to generate multilocus analysis.

Molecular and Biochemical Detection of Insecticide Resistance in the Leishmania Vector, Phlebotomus papatasi (Diptera: Psychodidae) to Dichlorodiphenyltrichloroethane and Pyrethroids, in Central Iran

The aim of the present study was to explore resistance markers and possible biochemical resistance mechanisms in the Phlebotomine sand fly Phlebotomus papatasi in Esfahan Province, central Iran. Homogenous resistant strains of sand flies were obtained by exposing P. papatasi collected from Esfahan to a single diagnostic dose of DDT. The adults from the colony were tested with papers impregnated with four pyrethroid insecticides: Permethrin 0.75%, Deltamethrin 0.05%, Cyfluthrin 0.15%, and Lambdacyhalothrin 0.05% to determine levels of cross-resistance. To discover the presence of mutations, a 440 base pair fragment of the voltage gated sodium channel (VGSC) gene was amplified and sequenced in both directions for the susceptible and resistant colonies. We also assayed the amount of four enzymes that play a key role in insecticide detoxification in the resistant colonies. A resistance ratio (RR) of 2.52 folds was achieved during the selection of resistant strains. Sequence analysis revealed no knockdown resistance (kdr) mutations in the VGSC gene. Enzyme activity ratio of the resistant candidate and susceptible colonies were calculated for α-esterases (3.78), β-esterases (3.72), mixed function oxidases (MFO) (3.21), and glutathione-S-transferases (GST) (1.59). No cross-resistance to the four pyrethroids insecticides was observed in the DDT resistant colony. The absence of kdr mutations in the VGSC gene suggests that alterations in esterase and MFO enzymes are responsible for the resistant of P. papatasi to DDT in central Iran. This information could have significant predictive utility in managing insecticide resistant in this Leishmania vector.

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.

Investigation of Phlebotominae (Diptera: Psychodidae) Fauna, Seasonal Dynamics, and Natural Leishmania spp. Infection in Muğla, Southwest of Turkey

Due to its geographical location, Muğla province is one of the most frequently used places by refugees. Although leishmaniasis have been previously reported in this region, there is a lack of information on the etiological agent and possible vectors. The main objectives of this study were; i) to investigate the sand fly fauna, ii) to reveal the natural Leishmania spp. infection in wild caught sand flies using molecular tools, and iii) to determine the annual seasonal dynamics of the sand flies in Muğla region. Totally, 2093 specimens belonging to 15 species [12 Phlebotomus, three Sergentomyia; 51 unidentified] were collected during the one-year (June 2016- June 2017) period. Of the collected sand flies, 1928 (92.12%) were caught by the Centers for Disease Control (CDC) light traps, while 165 (7.88%) of them were caught by sticky traps. Phlebotomus major sensu lato (s.l.), the potential vector of visceral leishmaniasis (VL) and canine leishmaniasis (CanL) in the Mediterranean and Aegean region, was detected in all sampling locations and found as the dominant taxon (n=1035; 49.45%) of the study area and followed by Phlebotomus tobbi (n=371; 17.72%). During the sampling period, sand fly activity was started in March and peaked in August. Sand fly population size reduced dramatically between mid-September and early October. The number of collected specimens was peaked in August, while there is only one sample collected both in November and March. The majority of the sand flies (78.66%) were collected at an altitude range of 200-400 m. Seventy-two monospecific pools were screened for the presence of Leishmania DNA by real time ITS1 PCR and 24 (nine P. major s.l., eight P. tobbi, two P. papatasi, two S. minuta, one P. alexandri, one P. similis, and one Phlebotomus (Transphlebotomus spp.) of them (33.8%) were found positive (L. infantum, L. tropica, and L. major). To the best of our knowledge, the presence of fifteen sand fly species and their distribution, seasonal dynamics, molecular detection of Leishmania parasites in Muğla province was reported for the first time. The presence of vector species in the study area, appropriate temperature and humidity conditions, long sand fly activity season, and presence of Leishmania parasite suggests that there is a serious risk in the transmission of leishmaniasis in Muğla.

Sand Fly (Diptera: Psychodidae: Phlebotominae) Population Dynamics and Natural Leishmania Infections in Attica Region, Greece

A 2-yr sand fly (Diptera: Psychodidae) seasonality study was performed in Attica Region, Greece, from June 2017 until November 2018, aiming also to detect the presence of Leishmania infection in the collected sand flies. In total, 701 sand flies were collected from urban areas within the Attica Region using BG-Sentinel traps, set weekly in eight fixed sites. Five species were identified morphologically and molecularly, namely Phlebotomus tobbi (Adler and Theodor), which was most the most commonly collected species, followed by P. Neglectus (Tonnoir), P. papatasi (Scopoli), P. simici (Theodor), and Sergentomyia minuta (Rondani). During both survey years sand fly populations peaked in late August to early September. Fifty-nine monospecific pools were examined for Leishmania detection by analyzing the ITS1 nuclear region using both RFLPs and sequencing, seven of which were found positive. Leishmania DNA was identified as L. infantum in six pools (five P. papatasi and one P. tobbi), whereas in one P. papatasi pool Leishmania DNA was identified as L. tropica. This is the first time that L. tropica has been detected in naturally infected sand flies from the Attica Region as well as in central Greece, while previously it has only been detected in sand flies collected from Central Macedonia (Northern Greece).

Phlebotomus (Adlerius) simici NITZULESCU, 1931: first record in Austria and phylogenetic relationship with other Adlerius species

Background

Phlebotomine sand flies are the principal vectors of Leishmania spp. (Kinetoplastida: Trypanosomatidae). Information on sand flies in Central Europe is scarce and, to date, in Austria, only Phlebotomus mascittii has been recorded. In 2018 and 2019, entomological surveys were conducted in Austria with the aim to further clarify sand fly distribution and species composition.

Results

In 2019, a Ph. simici specimen was trapped in Austria for the first time. Analyses of two commonly used marker genes, cytochrome c oxidase I (coxI) and cytochrome b (cytb), revealed high sequence identity with Ph. simici specimens from North Macedonia and Greece. Phylogenetic analyses showed high intraspecific distances within Ph. simici, thereby dividing this species into three lineages: one each from Europe, Turkey and Israel. Low interspecific distances between Ph. simici, Ph. brevis and an as yet unidentified Adlerius sp. from Turkey and Armenia highlight how challenging molecular identification within the Adlerius complex can be, even when standard marker genes are applied.

Conclusion

To our knowledge, this study reports the first finding of Ph. simici in Austria, representing the northernmost recording of this species to date. Moreover, it reveals valuable insights into the phylogenetic relationships among species within the subgenus Adlerius. Phlebotomus simici is a suspected vector of L. infantum and therefore of medical and veterinary importance. Potential sand fly expansion in Central Europe due to climatic change and the increasing import of Leishmania-infected dogs from endemic areas support the need for further studies on sand fly distribution in Austria and Central Europe in general.

Graphic abstract

Studies of host preferences of wild-caught Phlebotomus orientalis and Ph. papatasi vectors of leishmaniasis in Sudan

Introduction

Understanding the feeding behavior and host choice of sand flies provides valuable information on vector-host relationships and elucidates the epidemiological patterns of leishmaniasis transmission. Blood meal analysis studies are essential for estimating the efficiency of pathogen transmission, assessing the relative human disease risk, and assist in identifying the other potential hosts of leishmaniasis. In Sudan and most of East Africa, there are large remaining gaps in knowledge regarding the feeding habits of phlebotomine vectors. The study aimed to identify the blood meal sources and, therefore, the host preferences of the principal vectors Phlebotomus orientalis and Ph. papatasi in leishmaniasis endemic areas of eastern and central Sudan.

Materials and methods

Sand flies were collected from two endemic villages in eastern and central Sudan using CDC light traps and sticky traps. The phlebotomine sand flies were morphologically and then molecularly identified. The source of blood meal of the engorged females was determined using a multiplex PCR methodology and specific primers of cytochrome b gene of mitochondrial DNA for human, goat, cow, and dog. The detection of the Leishmania parasite was done using PCR.

Results

The total number of collected female phlebotomine sand flies was 180. Morphological identification revealed the abundance of Ph. orientalis 103 (57.2%), Ph. papatasi 42 (23.3%), Ph. bergeroti 31 (17.2%), Ph. rodhaini 2 (1.1%) and Ph. duboscqi 2 (1.1%) in the study sites. Out of the 180 collected, 31 (17%) were blood-fed flies. Three species were blood-fed and molecularly identified: Ph. papatasi (N = 7, 22.6%), Ph. bergeroti (N = 9, 26%), and Ph. orientalis (N = 15, 48.4%). Blood meal analysis revealed human DNA in two Ph. orientalis (6.4%), hence, the anthropophilic index was 13.3%.

Conclusions

Multiplex PCR protocol described here allowed the identification of blood meal sources of many vertebrate species simultaneously. The results indicate that wild-caught Ph. orientalis are anthropophilic in the study areas. Further studies on larger blood-fed sample size are required to validate the potential applications of this technique in designing, monitoring and evaluating control programs, particularly in investigating the potential non-human hosts of leishmaniasis.

Population dynamics, pathogen detection and insecticide resistance of mosquito and sand fly in refugee camps, Greece

BACKGROUND

As of 2015 thousands of refugees are being hosted in temporary refugee camps in Greece. Displaced populations, travelling and living under poor conditions with limited access to healthcare are at a high risk of exposure to vector borne disease (VBD). This study sought to evaluate the risk for VBD transmission within refugee camps in Greece by analyzing the mosquito and sand fly populations present, in light of designing effective and efficient context specific vector and disease control programs.

METHODS

A vector/pathogen surveillance network targeting mosquitoes and sand flies was deployed in four temporary refugee camps in Greece. Sample collections were conducted bi-weekly during June-September 2017 with the use of Centers for Disease Control (CDC) light traps and oviposition traps. Using conventional and molecular diagnostic tools we investigated the mosquito/sand fly species composition, population dynamics, pathogen infection rates, and insecticide resistance status in the major vector species.

RESULTS

Important disease vectors including Anopheles sacharovi, Culex pipiens, Aedes albopictus and the Leishmania vectors Phlebotomus neglectus, P. perfiliewi and P. tobbi were recorded in the study refugee camps. No mosquito pathogens (Plasmodium parasites, flaviviruses) were detected in the analysed samples yet high sand fly Leishmania infection rates are reported. Culex pipiens mosquitoes displayed relatively high knock down resistance (kdr) mutation allelic frequencies (ranging from 41.0 to 63.3%) while kdr mutations were also detected in Ae. albopictus populations, but not in Anopheles and sand fly specimens. No diflubenzuron (DFB) mutations were detected in any of the mosquito species analysed.

CONCLUSIONS

Important disease vectors and pathogens in vectors (Leishmania spp.) were recorded in the refugee camps indicating a situational risk factor for disease transmission. The Cx. pipiens and Ae. albopictus kdr mutation frequencies recorded pose a potential threat against the effectiveness of pyrethroid insecticides in these settings. In contrast, pyrethroids appear suitable for the control of Anopheles mosquitoes and sand flies and DFB for Cx. pipiens and Ae. albopictus larvicide applications. Targeted actions ensuring adequate living conditions and the establishment of integrated vector-borne disease surveillance programs in refugee settlements are essential for protecting refugee populations against VBDs.

Nutrition, malnutrition, and leishmaniasis

Leishmaniasis is a vector-borne infectious disease with a long history of infecting humans and other animals. It is a known emerging or resurging disease. The host nutritional state has an indispensable role in defense against pathogens. The host defense system disorganization as a result of undernutrition is responsible for asymptomatic infections and even severe diseases. Host susceptibility and pathophysiologic severity to infection can be aggravated owing to undernourishment in a number of pathways, and infection also may aggravate preexisting poor nutrition or further increase host susceptibility. This study suggests that there may be some relationship between malnutrition and the endemicity of the parasite. The susceptibility to and severity of leishmanial infection can be altered by the body weight and serum levels of micronutrients. Nutrition not only affects the vulnerability of the host but also may affect the desire of sandfly to bite a specific host. Apart from host defense mechanism, nutritional stress also greatly influences vector competence and host-seeking behavior, especially during larvae development. The host and sandfly vector nutritional states could also influence the evolution of the parasite. It is essential to elucidate the roles that diets and nutrition play in the leishmanial life cycle. The aim of this article is to review the influences of nutrition and diets on the host susceptibility and severity of infection, preemptive and therapeutic strategy feedback, parasite evolution, and vector competence.

A novel MALDI-TOF MS-based method for blood meal identification in insect vectors: A proof of concept study on phlebotomine sand flies

Background

Identification of blood sources of hematophagous arthropods is crucial for understanding the transmission cycles of vector-borne diseases. Many different approaches towards host determination were proposed, including precipitin test, ELISA, DNA- and mass spectrometry-based methods; yet all face certain complications and limitations, mostly related to blood degradation. This study presents a novel method for blood meal identification, peptide mass mapping (PMM) analysis of host-specific hemoglobin peptides using MALDI-TOF mass spectrometry.

Methodology/Principal findings

To identify blood meal source, proteins from abdomens of engorged sand fly females were extracted, cleaved by trypsin and peptide fragments of host hemoglobin were sequenced using MALDI-TOF MS. The method provided correct host identification of 100% experimentally fed sand flies until 36h post blood meal (PBM) and for 80% samples even 48h PBM. In females fed on two hosts, both blood meal sources were correctly assigned for 60% of specimens until 36h PBM. In a validation study on field-collected females, the method yielded unambiguous host determination for 96% of specimens. The suitability of PMM-based MALDI-TOF MS was proven experimentally also on lab-reared Culex mosquitoes.

Conclusions/Significance

PMM-based MALDI-TOF MS analysis targeting host specific hemoglobin peptides represents a sensitive and cost-effective method with a fast and simple preparation protocol. As demonstrated here on phlebotomine sand flies and mosquitoes, it allows reliable and rapid blood source determination even 48h PBM with minimal material input and provides more robust and specific results than other currently used methods. This approach was also successfully tested on field-caught engorged females and proved to be a promising useful tool for large-scale screening of host preferences studies. Unlike other methods including MALDI-TOF protein profiling, it allows correct identification of mixed blood meals as was demonstrated on both experimentally fed and field-collected sand flies.

Leishmaniases belong among the most important and yet neglected vector-borne diseases, transmitted mostly by bite of female phlebotomine sand flies. To understand role of different reservoir hosts in the transmission cycles, it is important to determine blood meal sources of bloodfeeding females. Most of currently used methods face challenges due to tiny volumes of engorged blood, in case of mammals also enucleated, as well as quick progress of blood digestion which leads to rapid DNA and protein degradation. New approach towards blood source determination presented in this study is based on MALDI-TOF mass spectrometry that identifies unique peptide sequences of host hemoglobins, showing high precision and sensitivity together with a longer time period for successful host determination when compared to nowadays standardly used DNA sequencing. It was tested and verified on engorged phlebotomine sand flies from both laboratory colonies and natural endemic areas and also on Culex mosquitoes and shall be universal to hematophagous insects. Beside blood meal identification, it allows also the use of both morphological and molecular methods (DNA- or protein-based) for the species identification of the analysed specimen.

Effects of land use type, spatial patterns and host presence on Leishmania tropica vectors activity

BACKGROUND

Leishmaniasis is a vector-borne disease, caused by the infection of Leishmania parasites which are transmitted by the bite of infected female phlebotomine sand flies. Leishmania tropica is transmitted by Phlebotomus sergenti and Phlebotomus arabicus while the main reservoir host is the rock hyrax. A marked increase in the incidence of cutaneous leishmaniasis (CL) caused by L. tropica has been detected in recent years in Israel; it is associated with infections which have emerged in new urban and rural foci. The objective of this study is to contribute to a better understanding of the preferred habitat, spatial activities and host-sand fly relationships of both species of vectors within various types of land use.

METHODS

Using CDC-type traps, we investigated the activity levels of sand flies. A field survey was conducted in 2016 at Elifelet, an agricultural village characterized by various types of land use. Movement patterns of P. sergenti between rock-piles were investigated by using colour-marked sugar baits and analyses of recapture patterns. In 2017, a survey was conducted in the hilly Jordan River area, by comparing sand flies and rock hyrax activities in relation to the size of rock-piles and vegetation cover.

RESULTS

Both sexes of both species were found to have a clear preference for rocky habitats over other land use types in rural landscapes. Movement patterns of P. sergenti were characterized by their high presence close to the rocks and an exponential decrease in their recapture, commensurate with the distance from the rocks. Host-sand fly relationships were found to have a higher correlation between rock hyrax activity levels for females than for males of both species of sand flies. Males exhibited the strongest association with the size of rock-piles.

CONCLUSIONS

The results suggest a strong affinity of both phlebotomine vector species to the rocky habitats of the Mediterranean areas. We suggest that rock-piles are associated with populations of rock hyraxes attracting female sand flies seeking blood sources. Rapid human population growth, coupled with intensive land-use changes and the creation of artificial rock-piles, which created potential habitats for both vectors and hosts in the proximity of many settlements, have increased the prevalence of L. tropica among the human population in the region.

Seasonal dynamics of a population of Phlebotomus (Larroussius) perfiliewi Parrot, 1930 (Diptera: Psychodidae) in North-Eastern Romania

Sand flies were collected in a location from Romania in order to estimate their abundance and seasonal variation in correlation with environmental and anthropic factors. From May to October 2017, eight premises with different animal species were sampled for sand flies in a household from Fundătura village, Vaslui County, in North-Eastern Romania. Animal-related data, shelter-related data, and climatic parameters were recorded. All (n = 150) collected sand flies were Phlebotomus perfiliewi. A mono-modal type of abundance trend has been recorded (a single peak at the beginning of August). The first day of capture was in mid-July. The total number of females during the peak season was significantly higher than the total number of males. The highest percentage of males was recorded at the beginning and at the end of the sand fly activity. Only the traps placed in the poultry enclosure built from clay and wood were positive. A strong positive correlation was recorded between the total number of collected sand flies and the minimum and the maximum temperature. The analysis of the climatic data shows that the first presence of sand flies was registered only after the average minimum temperature for the previous 7 days was above 15 °C.

Host use patterns of Culicoides spp. biting midges at a big game preserve in Florida, U.S.A., and implications for the transmission of orbiviruses

Culicoides spp. biting midges (Diptera: Ceratopogonidae) are vectors of pathogens that have a significant economic impact on the livestock industry. White-tailed deer (Odocoileus virginianus), a farmed species in the U.S.A., are susceptible to two Culicoides spp. borne orbiviruses: bluetongue virus and epizootic haemorrhagic disease virus. Elucidating host-vector interactions is an integral step in studying disease transmission. This study investigated the host range of Culicoides spp. present on a big game preserve in Florida on which a variety of Cervidae and Bovidae freely roam. Culicoides were captured with Centers for Disease Control and Prevention (CDC) miniature light traps run twice weekly on the preserve for 18 consecutive months (July 2015-December 2016). Host preference was quantified through forage ratios, based upon PCR-based bloodmeal analysis of Culicoides spp. and overall animal relative abundance on the preserve. Culicoides stellifer preferentially fed on Cervus spp. and fallow deer (Dama dama) and displayed a relative avoidance of Bovidae and white-tailed deer. Culicoides debilipalpis preferred white-tailed deer and avoided all Bovidae. Culicoides pallidicornis and Culicoides biguttatus showed preferences for white-tailed deer and Père David's deer (Elaphurus davidianus), respectively. These results add to current knowledge of preferred hosts of Florida Culicoides spp. and have implications for the spread of orbiviruses. Copyright © 2018 John Wiley & Sons, Ltd.

Identification of Leishmania Species in Naturally Infected Sand Flies from Refugee Camps, Greece

High infection rates of Leishmania donovani and L. tropica were detected in Phlebotomus spp. sand flies collected from refugee camps in Greece, indicating increased risk of infection among local populations. Detection and treatment of leishmaniasis, community education, and vector control are essential measures to prevent pathogen transmission and protect public health.

A Comparative Study of Mosquito and Sand Fly (Diptera: Psychodidae: Phlebotominae) Sampling Using Dry Ice and Chemically Generated Carbon Dioxide From Three Different Prototype CO2 Generators

A comparative study was conducted to test the efficiency of Centers for Disease Control and Prevention (CDC) light traps baited with either dry ice or carbon dioxide (CO2) produced from one of three different sources in collecting mosquitoes (Diptera: Culicidae) in Thailand. Treatments consisted of dry ice pellets, CO2 gas produced from one of three prototype CO2 generator systems (TDA, CUBE, Moustiq-Air Med-e-Cell - MEC), and a CDC light trap without a CO2 source. The best performing prototype from Thailand was then tested in collecting sand flies (Diptera: Psychodidae: Phlebotominae) in Greece. A total of 12,798 mosquitoes and 8,329 sand flies were sampled during the experimentation. The most prevalent mosquito species collected in Thailand were: Culex vishnui Theobald > Anopheles minimus Theobald > Culex tritaeniorhynchus Giles > Anopheles sawadwongporni Rattanarithikul & Green. By far the most prevalent sand fly species collected in Thessaloniki was Phlebotomus perfiliewi Parrot followed by Phlebotomus tobbi Adler and Theodor and Phlebotomus simici Nitzulescu. In general, the TDA treatment was the only treatment with no significant difference from the dry ice-treatment in mean trap catches. Although dry ice-baited traps caught higher numbers of mosquitoes and sand flies than the TDA-baited traps, there was no difference in the number of species collected. Results indicate that the traps baited with the TDA CO2 generator were as attractive as traps supplied with dry ice and, therefore, the TDA CO2 generator is a suitable alternative to dry ice as a source of carbon dioxide for use with adult mosquito and sand fly traps.

Broadening the tools for studying sand fly breeding habitats: A novel molecular approach for the detection of phlebotomine larval DNA in soil substrates

Phlebotomine sand flies constitute a group of haematophagous insects of great medical and veterinary importance. Despite the significant knowledge on the biology and behavior of adult sand flies in the wild, there is little information available on the ecology of their larval stages due to difficulties of detecting them in the soil. So far, investigations on sand fly breeding sites have been based on methods to catch emerging adults or on microscopic examination of the soil for the presence of immatures, neither of which is very precise or efficient for studying immatures in the field. Thus, there is a need for a better method to detect, identify and quantify immatures in soil samples. To address this issue we developed a novel molecular genetic approach for the detection of sand fly larval DNA within soil samples. Different numbers of live larvae of Phlebotomus papatasi and P. tobbi (alone or in combination), were mixed with soil and analyzed to identify and quantify the sand flies. By modifying already existing soil DNA extraction protocols in combination with a real-time PCR using species-specific primers, we successfully detected as little as one larva/40 ml of soil. We could also distinguish the two species of sand flies. This method should be very useful for increasing our knowledge of sand fly larval ecology in the field, and thus help develop more efficient, targeted control strategies against Phlebotomus sand flies.

Detection of Pyrethroid Resistance Mutations in the Major Leishmaniasis Vector Phlebotomus papatasi

Phlebotomine sand flies (Diptera: Psychodidae) are primary vectors of leishmaniasis. Greece and Turkey are both endemic for visceral and cutaneous leishmaniasis and are widely affected by the disease. Measures commonly applied for controlling sand flies rely on the use of insecticides, predominantly pyrethroids. A worldwide problem associated with the intensive use of insecticides is the development of resistance. Scarce information is available regarding the resistance status in sand fly populations. Sand flies were collected from Greece (Thessaloniki, Peloponnese, Chios island) and Turkey (Sanliurfa) and analyzed for the presence and frequency of target-site knockdown resistance mutations on the voltage-gated sodium channel (Vgsc) gene. Five sand fly species were included in the analysis: Phlebotomus perfiliewi Parrot, Phlebotomus neglectus Tonnoir, Phlebotomus simici Nitzulescu, Phlebotomus tobbi Adler and Theodor, and Phlebotomus papatasi Scopoli. Their Vgsc gene-domain II was analyzed for the presence of known pyrethroid resistance mutations. The mutation 1014F, associated with pyrethroid-resistant phenotypes, was detected in P. papatasi sand flies from Sanliurfa at an allele frequency of 48%. Homozygotes for the wild type allele 1014L (Leu/Leu) represented 36% of the population, while homozygotes for the resistant allele 1014F (Phe/Phe) and heterozygotes encompassing both alleles (Leu/Phe) each had a frequency of 32%. In all other sand fly species, only the wild type allele 1014L was detected. This is the first report for the detection of resistance mutations in the major leishmaniasis vector P. papatasi and is of major concern regarding leishmaniasis control.

Ground ultra low volume (ULV) space spray applications for the control of wild sand fly populations (Psychodidae: Phlebotominae) in Europe

The Phlebotomus sand flies are considered an important vector of both canine and human leishmaniasis. Current measures for sand fly control include mostly indoor interventions, such as residual spraying of dwellings (IRS) to target endophilic sand fly species with very limited number of vector control tools for outdoor interventions against exophilic sand flies. In this study we investigated the efficacy of ground ultra low volume (ULV) space spray applications of a deltamethrin based product against field populations of P. perfiliewi, a major nuisance and pathogen-transmitting sand fly species of the Mediterranean Basin. Sand fly flight activity patterns and flight height preference within candidate treatment sites (kennels) were determined prior to treatments in order to optimize the timing and application parameters of the spray applications. On average there was a distinct activity peak between 20.00-22.00 h for both male and female P. perfiliewi with more than 45% and 30% of the population sampled occurring between 20.00-21.00 h and 21.00-22.00 h, respectively. No significant difference was observed in sand fly numbers from sticky traps placed at 0.5 up to 1.5 m height. However, there was a significant decrease in sand fly numbers at 2 m indicating a preference of sand flies to fly below 2 m. The low and high application rate of deltamethrin resulted in mean sand fly population decrease of 18 and 66%, respectively between pre-and post-treatment trap nights. The percent mean population change in the untreated control area was a positive number (30%) indicating that there was an increase in numbers of sand flies trapped between pre- and post-treatment nights. The results of this study provide strong evidence that ground ULV space spray applications when applied properly can result in significant sand fly control levels, even in a heavily infested sand fly environment such as the kennel sites used in this study.

Identification of wild-caught phlebotomine sand flies from Crete and Cyprus using DNA barcoding

Background

Phlebotomine sand flies (Diptera: Psychodidae) are vectors of Leishmania spp., protozoan parasites responsible for a group of neglected diseases called leishmaniases. Two sand fly genera, Phlebotomus and Sergentomyia, contain species that are present in the Mediterranean islands of Crete and Cyprus where the visceral (VL), cutaneous (CL) and canine (CanLei) leishmaniases are a public health concern. The risk of transmission of different Leishmania species can be studied in an area by monitoring their vectors. Sand fly species are traditionally identified using morphological characteristics but minute differences between individuals or populations could be overlooked leading to wrong epidemiological predictions. Molecular identification of these important vectors has become, therefore, an essential tool for research tasks concerning their geographical distribution which directly relates to leishmaniasis control efforts. DNA barcoding is a widely used molecular identification method for cataloguing animal species by sequencing a fragment of the mitochondrial gene encoding cytochrome oxidase I.

Results

DNA barcoding was used to identify individuals of five sand fly species (Phlebotomus papatasi, P. similis, P. killicki, Sergentomyia minuta, S. dentata) circulating in the islands of Crete and Cyprus during the years 2011–2014. Phlebotomus papatasi is a known vector of zoonotic CL in the Middle East and it is found in both islands. Phlebotomus similis is the suspected vector of Leishmania tropica in Greece causing anthroponotic CL. Phlebotomus killicki was collected in Cyprus for the first time. Sergentomyia minuta, found to present intraspecific diversity, is discussed for its potential as a Leishmania vector. Molecular identification was consistent with the morphological identification. It successfully identified males and females, which is difficult when using only morphological characters. A phylogenetic tree was constructed based on the barcodes acquired, representing their genetic relationships along with other species from the area studied. All individuals identified were clustered according to their species and subgenus.

Conclusions

Molecular identification of sand flies via DNA barcoding can accurately identify these medically important insects assisting traditional morphological tools, thus helping to assess their implication in Leishmania transmission.

Direct Multiplex PCR (dmPCR) for the Identification of Six Phlebotomine Sand Fly Species (Diptera: Psychodidae), Including Major Leishmania Vectors of the Mediterranean

Sand flies (Diptera: Psychodidae, subfamily Phlebotominae) are hematophagous insects that are known to transmit several anthroponotic and zoonotic diseases. Reliable identification of sand flies at species level is crucial for their surveillance, the detection and spread of their pathogens, and the implementation of targeted pest control strategies. Here, we designed a novel, time-saving, cost-effective and easy-to-apply molecular methodology, which avoids sequencing, for the identification of the following six Eastern Mediterranean sand fly species: Phebotomus perfiliewi Parrot, Phebotomus simici Theodor, Phebotomus tobbi Adler and Theodor, Phebotomus papatasi Scopoli, Sergentomyia dentata Sinton, and Sergentomyia minuta Theodor. This methodology, which is a multiplex PCR assay using one common and six diagnostic primers, is based on species-specific single-nucleotide polymorphisms of the nuclear 18S rRNA gene. Amplification products were easily and reliably separated in agarose gel yielding one single clear band of diagnostic size for each species. Further, we verified its successful application on tissue samples that were immersed directly to the PCR mix, skipping DNA extraction. The direct multiplex PCR can be completed in < 3 h, including all operating procedures, and costing no more than a simple PCR. The applicability of this methodology in the detection of hybrids is an additional considerable benefit.

DNA sequencing confirms PCR-RFLP identification of wild caught Larroussius sand flies from Crete and Cyprus

Many Phlebotomine sand fly species (Diptera, Psychodidae) are vectors of the protozoan parasite Leishmania causing a group of diseases called the leishmaniases. The subgenus Larroussius includes sand fly vectors found in South East Mediterranean Basin responsible for Visceral (VL) and Cutaneous human leishmaniasis (CL). It is important to monitor these medically important insects in order to safely predict possible Leishmania transmission cycles. Leishmania infantum is endemic in the islands of Crete and Cyprus with increasing VL cases in humans and dogs and in Cyprus the newly introduced Leishmania donovani causes both VL and CL in humans. The morphological identification of the females of the subgenus Larroussius often presents difficulties. Morphology and COI PCR - RFLP were used to identify wild caught Larroussius sand flies belonging to Phlebotomus tobbi, P. perfiliewi, and P. neglectus species from Crete and Cyprus. The identification results were further confirmed by sequencing (DNA barcoding) and Bayesian phylogenetic analysis. COI PCR - RFLP, when correctly optimized and with respect to geographical origin, can serve as an initial patterning identification tool when large sand fly numbers need to be identified. It could accurately assign Larroussius females and males to their taxa overcoming the difficulties of morphological identification. Finally, DNA barcoding will contribute to a molecular identification database to be used for in-depth species studies.