Cutaneous leishmaniasis caused by Leishmania infantum transmitted by Phlebotomus tobbi

First Detection and Molecular Analysis of Leishmania infantum DNA in Sand Flies of Kosovo

Phlebotomine sand flies (Diptera: Psychodidae) are the principal vectors of phleboviruses and Leishmania spp., the causative agents of leishmaniases. The Mediterranean sand fly fauna is diverse, and leishmaniasis, mainly caused by Leishmania infantum, is endemic in the Balkan countries. Despite recent entomological surveys, only some districts of Kosovo have been sampled for sand flies, with no proof/confirmation of L. infantum. This study aimed to gain further insights into the species composition of natural sand fly populations in previously unsampled districts and areas in Kosovo without reports of leishmaniasis and to detect Leishmania DNA in sand flies. A sand fly survey was conducted in 2022 in all seven districts of Kosovo. Collected females were screened for Leishmania DNA by PCR. Positive samples were sequenced and subjected to maximum likelihood analysis with reference sequences for further molecular characterization. The trapping activities at 114 different localities resulted in 3272 caught specimens, comprising seven sand fly species of two genera, namely Phlebotomus neglectus, Ph. perfiliewi, Ph. tobbi, Ph. papatasi, Ph. simici, Ph. balcanicus and Sergentomyia minuta. Leishmania infantum DNA was detected in three individual sand flies of Ph. neglectus and Ph. perfiliewi. This study provides the most extensive sand fly survey in Kosovo and reports the first record of L. infantum DNA in sand flies, indicating autochthonous circulation of L. infantum.

Diagnostic Tools for Cutaneous Leishmaniasis Caused by Leishmania donovani: A Narrative Review

Leishmaniasis, a neglected tropical disease, encompasses a spectrum of clinical conditions and poses a significant risk of infection to over one billion people worldwide. Visceral leishmaniasis (VL) in the Indian sub-continent (ISC), where the causative parasite is Leishmania donovani, is targeted for elimination by 2025, with some countries already reaching such targets. Other clinical phenotypes due to the same species could act as a reservoir of parasites and thus pose a challenge to successful control and elimination. Sri Lanka has consistently reported cutaneous leishmaniasis (CL) due to L. donovani as the primary disease presentation over several decades. Similar findings of atypical phenotypes of L. donovani have also been reported from several other countries/regions in the Old World. In this review, we discuss the applicability of different methods in diagnosing CL due to L. donovani and a comprehensive assessment of diagnostic methods spanning clinical, microscopic, molecular, and immunological approaches. By incorporating evidence from Sri Lanka and other regions on L. donovani-related CL, we thoroughly evaluate the accuracy, feasibility, and relevance of these diagnostic tools. We also discuss the challenges and complexities linked to diagnosing CL and review novel approaches and their applicability for detecting CL.

Cutaneous Leishmaniasis Caused by Leishmania infantum, Israel, 2018-2021

Cutaneous leishmaniasis (CL) is endemic to Israel. Previously, CL caused by Leishmania infantum had been reported in Israel only once (in 2016). We report 8 L. infantum CL cases; 7 occurred during 2020-2021. None of the patients had systemic disease. L. infantum CL may be an emerging infection in Israel.

Differential expression of Phlebotomus tobbi Adler, Theodor & Lourie, 1930 (Diptera: Psychodidae) genes under different environmental conditions

Phlebotomus tobbi is a widely distributed sand fly species in Turkey and is the proven vector of Leishmania infantum and several Phleboviruses. Information regarding the genetic basis of phenotypic plasticity is crucial for managing vector-borne diseases, as the changing environmental conditions have consequences for the survival of arthropods and the disease agents they transmit. However, limited data is available on the impacts of environmental conditions on the traits associated with sand fly survival, reproduction, and vectorial competence. The present study aimed to reveal the changes in the expression levels of three selected P. tobbi genes using laboratory-reared and wild-caught populations. A nervous system protein, Cacophony (PtCac), related to the life history traits of sand flies, and two sand fly salivary protein genes, PtSP32 and PtSP38, influence the infection of the vertebrate hosts, were assessed. Sand flies were maintained at 23 °C and 27 °C in the laboratory to evaluate the relationship between temperature and the expressed phenotypes. Field collections were carried out in three climatically distinct regions of Turkey to establish the regional differences in the gene expression levels of natural P. tobbi populations. In the laboratory, PtCac expression increased with the temperature. However, PtCac expression was negatively correlated with local temperature and humidity conditions. No differences were detected in the PtSP32 gene expression levels of both laboratory-reared and wild-caught females, but a negative correlation was observed with relative humidity in natural populations. Although the expression levels of PtSP38 did not differ among the females collected from distinct regions, a positive correlation was detected in the laboratory-reared colony. The findings indicated that changes in environmental conditions could drive the expression levels of P. tobbi genes, which influence population dynamics and the transmission risk of the disease.

Unusual Observations in Leishmaniasis-An Overview

Leishmaniasis significantly affects the population of the tropics and subtropics. Clinical features and infective species of Leishmania are the primary factors driving the direction of diagnosis. The rise in incidences of atypical presentations present a challenge in patient treatment. Knowledge of unusual/rare presentations can aid in having a broader perspective for including the different aspects during the examination and thus avoid misdiagnosis. A comprehensive literature survey was performed to present the array of atypical presentations confounding clinicians which have been seen in leishmaniasis. Case reports of unusual findings based on the localizations and morphology of lesions and infective species and the predominant geographical sites over almost five decades highlight such presentations in the population. Information regarding the clinical features recorded in the patient and the chosen treatment was extracted to put forward the preferred drug regimen in such cases. This comprehensive review presents various unusual observations seen in visceral leishmaniasis, post-kala-azar dermal leishmaniasis, cutaneous leishmaniasis, and mucocutaneous leishmaniasis. It highlights the need to consider such features in association with differential diagnosis to facilitate proper treatment of the patient.

First Report of Two Jaculus Rodents as Potential Reservoir Hosts of Leishmania Parasites in Tunisia

This study shows, for the first time, natural Leishmania infection among Jaculus spp. in an endemic region of Tataouine, South Tunisia. To better characterize the transmission cycles in this complex focus of mixed transmission, Leishmania detection and species identification were performed by direct examination, internal transcribed spacer-1 (ITS1)-PCR-restriction fragment length polymorphism (RFLP), and sequencing of Jaculus (J.) jaculus (Linnaeus, 1758) and J. hirtipes (Lichtenstein, 1823) rodent species, which are frequently encountered in this area. Leishmania parasites were observed in 19 (41.3%) smears, while DNA parasites were detected in 28 (60.9%) Jaculus spp. spleens; among them, 12 (54.5%) were from 22 J. jaculus individuals and 16 (66.7%) were from 24 J. hirtipes individuals. Leishmania parasites were confirmed as Leishmania (L.) killicki (syn. L. tropica) in two J. hirtipes individuals (4.3%) and L. major (n = 24; 52.2%) in 10 J. jaculus and 14 J. hirtipes individuals. This finding represents the first evidence of natural infection with Leishmania parasites in rodents belonging to the Jaculus genus, providing the rationale to consider them as potential reservoir hosts of Old World Leishmania parasites in Tunisia and North Africa.

Assembly of a Large Collection of Maxicircle Sequences and Their Usefulness for Leishmania Taxonomy and Strain Typing

Parasites of medical importance, such as Leishmania and Trypanosoma, are characterized by the presence of thousands of circular DNA molecules forming a structure known as kinetoplast, within the mitochondria. The maxicircles, which are equivalent to the mitochondrial genome in other eukaryotes, have been proposed as a promising phylogenetic marker. Using whole-DNA sequencing data, it is also possible to assemble maxicircle sequences as shown here and in previous works. In this study, based on data available in public databases and using a bioinformatics workflow previously reported by our group, we assembled the complete coding region of the maxicircles for 26 prototypical strains of trypanosomatid species. Phylogenetic analysis based on this dataset resulted in a robust tree showing an accurate taxonomy of kinetoplastids, which was also able to discern between closely related Leishmania species that are usually difficult to discriminate by classical methodologies. In addition, we provide a dataset of the maxicircle sequences of 60 Leishmania infantum field isolates from America, Western Europe, North Africa, and Eastern Europe. In agreement with previous studies, our data indicate that L. infantum parasites from Brazil are highly homogeneous and closely related to European strains, which were transferred there during the discovery of America. However, this study showed the existence of different L. infantum populations/clades within the Mediterranean region. A maxicircle signature for each clade has been established. Interestingly, two L. infantum clades were found coexisting in the same region of Spain, one similar to the American strains, represented by the Spanish JPCM5 reference strain, and the other, named “non-JPC like”, may be related to an important leishmaniasis outbreak that occurred in Madrid a few years ago. In conclusion, the maxicircle sequence emerges as a robust molecular marker for phylogenetic analysis and species typing within the kinetoplastids, which also has the potential to discriminate intraspecific variability.

Blood Meal Analysis and Molecular Detection of Leishmania DNA in Wild-Caught Sand Flies in Leishmaniasis Endemic Areas of Turkey and Northern Cyprus

INTRODUCTION

Phlebotomine sand flies (Diptera: Psychodidae) are known as the vector of diseases such as leishmaniasis, bartonellosis and viral diseases. The aim of this study is to detect the host feeding pattern of sand flies in the endemic areas for leishmaniasis in Turkey (Antalya, Kayseri) and Northern Cyprus (TRNC) as well as the presence of Leishmania DNA in the specimens.

METHODS

One-hundred seventy-six blood-fed sand fly specimens were examined for blood meal analysis. A SYBR Green-PCR assay was performed with specific forward primers for each host and a universal reverse primer. Primers of human and goat were used together in multiplex PCR while goat and cow were studied separately. ITS-1 qPCR assay was also performed on both blood-fed and non-blood-fed females to detect Leishmania parasites.

RESULTS

Blood sources could be detected in 69 out of 176 blood-fed sand fly specimens. The results of blood meal analysis showed that specimens were fed mostly on cows (22.2%) followed by humans (5.7%), goats (2.8%) and dogs (0.6%). Multiple feeding patterns were also detected as human + cow (3.4%), cow + goat (2.8%) and human + goat (1.7%). Five of the blood-fed specimens were Leishmania spp. positive: P. major s.l. (n = 1), P. tobbi (n = 2) were L. tropica positive from Antalya, P. simici was positive for L. infantum from Kayseri and P. papatasi (n = 1) was positive for L. major from Cyprus. Leishmania infection rates were determined as 3.79%, 1.69% and 2.63% among the blood-fed sand fly specimens in Antalya, Kayseri and TRNC, respectively.

CONCLUSION

The SYBR-Green-based multiplex PCR assay is a cost-effective and promising tool for blood meal identification of wild-caught sand flies as well as other blood-sucking arthropods. Feeding patterns of important vector species detected in the present study show the high risk in these endemic areas. As a next step, to identify the blood source in a shorter time and to make the test more sensitive, development of this assay to probe-based and multiplex PCR will be also planned.

Identification of blood source preferences and Leishmania infection in sand flies (Diptera: Psychodidae) in north-eastern Algeria

Leishmaniases are among the most neglected vector-borne diseases, infecting humans as well various animal hosts with clinical outcomes varying from cutaneous disorders to visceral and life-threatening disease. In Algeria, canine leishmaniasis (CanL) caused by Leishmania infantum is endemic mainly throughout the northern regions of the country with the Mediterranean climate that favours the occurrence of Larroussius sand flies, the vectors of the parasite. This study conducted in Bougaa and Kherrata, two regions located in north-eastern Algeria and endemic for CanL, focuses on: i) composition of sand fly fauna, ii) screening of Leishmania parasites and iii) the blood sources of engorged females. Entomological surveys were conducted between June and September 2019 using CDC light-traps in rural areas of both regions. Sand fly specimens were morphologically identified, females were screened for Leishmania DNA using kDNA and ITS1 primers, blood meals in engorged females were identified by peptide mass mapping (PMM)-based MALDI-TOF mass spectrometry and confirmed by DNA sequencing analysis. Overall, 1940 specimens (844 males, 1096 females) were collected, all belonging to the subgenus Larroussius: Phlebotomus perniciosus, (94.64%), Ph. perfiliewi (4.74%) and Ph. longicuspis (0.62%). No Leishmania DNA was detected in the evaluated pools (n = 106) (1096 females). PMM-based MALDI-TOF MS successfully identified a source of blood in 92% (141/154) of engorged females (135 Ph. perniciosus and 6 Ph. perfiliewi). All blood meals were taken from domestic cattle (Bos taurus) except for one originating from a dog (Canis lupus familiaris) and one from sheep (Ovis aries). Sequencing of host cytochrome B gene confirmed these identifications but showed lower success rate of 58% (29/50), demonstrating the high effectivity of peptide mass mapping (PMM)-based MALDI-TOF mass spectrometry for routine identification of blood meals of varying degree of digestion. Our findings represent first record of cattle and dog blood in sand flies in Algeria and striking feeding preference of local sand fly population at domestic sites of studied regions for cattle which may play an important role in parasite transmission. Further studies are needed to better understand potential contribution of cattle to ecology of sand flies and epidemiology of leishmaniasis in north-eastern Algeria.

The current epidemiology of leishmaniasis in Turkey, Azerbaijan and Georgia and implications for disease emergence in European countries

Leishmania spp. are sand fly-borne protozoan parasites causing leishmaniasis in humans and animals. The aim of the study was to analyse the epidemiology of leishmaniasis in Turkey, Azerbaijan and Georgia from 2005 to 2020 and evaluate the associated risk for disease emergence in European countries. It is based on an analysis of WHO and OIE reported cases between 2005 and 2020, a review of scientific articles published in SCOPUS between 2009 and 2020 and a questionnaire survey to public health and veterinary authorities in these countries. Endemic Leishmania spp. include L. infantum in the three countries, L. major in Azerbaijan and Turkey and L. tropica and L. donovani in Turkey. Leishmaniasis is reported in humans, animals and sand flies and incidence is spatially and temporarily variable. In the southern Caucasus and particularly in Georgia, reported incidence of human visceral leishmaniasis by L. infantum remains high. However, whilst Georgia experienced a gradual decrease from >4.0 cases per 100,000 population in 2005-09 to 1.13 cases per 100,000 population in 2020, the period with highest incidence in Azerbaijan, which ranged between 0.40 and 0.61 cases per 100,000 population, was 2016-2019, and no cases have so far been reported for 2020. Visceral leishmaniasis in the Southern Caucasus affects mostly young children from deprived urban areas and its closely associated to canine leishmaniasis. Turkey reported cases of visceral leishmaniasis between 2005 and 2012 and in 2016 only, and incidence ranged between 0.02 and 0.05 per 100,000 population. In contrast, the reported annual incidence of cutaneous leishmaniasis in Turkey was much greater and peaked at 7.02 cases per 100,000 population in 2013, associated to imported cases from cutaneous leishmaniasis endemic Syria. Leishmaniasis by L. infantum in Azerbaijan and Georgia represents a regional public and animal health challenge that requires support to improve diagnosis, treatment and control. The unprecedented rise of cutaneous leishmaniasis and the spread of L. tropica and L. donovani in Turkey is an important risk factor for their emergence in Europe, especially in Mediterranean countries where competent vectors are widespread.

Fauna, Seasonal Activity, and Altitudinal Distribution of Phlebotomine Sand Flies (Diptera: Psychodidae) in Leishmaniasis Endemic Area, Aydın Mountains, and Surroundings in Western Turkey

OBJECTIVE

Human and canine leishmaniasis (CanL) are endemic in Turkey, and cutaneous leishmaniasis (CL) is a primary public health problem among vector-borne diseases, with 1500-2000 autochthonous cases per year. In this study, we aimed to perform a comprehensive entomological survey, including the detection of sand fly fauna, seasonal activity, and altitudinal distribution, together with the ecological features of Aydın Mountains and their surroundings that are endemic areas for CL caused by Leishmania tropica and CanL caused by L. infantum MON-1.

METHODS

The survey was carried out from June 2009 to July 2010. Ten localities with different altitudes were selected. Sand fly collection was done every 15 days in July and August when sand flies are most active and every 30 days between September and June (14 months, 16 samplings) using CDC light traps and sticky traps. During the collection, the temperature, humidity, and ecological and environmental features were recorded. Sand fly specimens were dissected and identified at species level using written keys.

RESULTS

A total of 6712 sand fly specimens (3268 females and 3444 males) were collected from 10 localities throughout all study periods. Species identification revealed that nine and three species belonging to Phlebotomus (P. major s.l. 30.38%, P. tobbi 22.93%, P. papatasi 5.88%, P. sergenti s.l. 4.51%, P. alexandri 4.26%, P. simici 3.50%, P. burneyi 0.63%, P. brevis 0.45%, and Transphlebotomus spp. 0.28%) and Sergentomyia (S. dentata 23.17%, S. minuta 2.43%, and S. antennata 1.58%) were found, respectively. The seasonal activities of these 12 sand fly species were determined, and P. major s.l. and P. tobbi, which were probable vectors of VL and CanL, were present in the study area. P. sergenti s.l., a probable vector of CL, was also found in the region and was active for seven months between April and October. P. sergenti s.l. was found in the 400-600 m altitude in July, while P. major and P. tobbi were found in high densities in the 200-400 m altitude in September.

CONCLUSION

Our results showed that leishmaniasis vectors are present in different altitudes in the Aydın mountains and surroundings. The findings revealed the time intervals of parasite transmission in the area and the period of applying protective measures, such as insecticide application.

Phlebotomine Sand Flies in Southern Thailand: Entomological Survey, Identification of Blood Meals and Molecular Detection of Trypanosoma spp

Simple Summary

Phlebotomine sand flies (Diptera: Psychodidae) are hematophagous insects, and many species serve as vectors of various human and animal pathogens, including Leishmania and Trypanosoma protozoa. In Thailand, the first case of autochthonous leishmaniasis was reported 62 years ago. At present, the number of human cases is increasing in different regions of the country, but most cases are reported from southern Thailand. Therefore, we studied the potential transmission of Leishmania and Trypanosoma by sand flies in three provinces of southern Thailand, and analyzed blood sources of engorged sand fly females. We detected Trypanosoma sp. DNA in Sergentomyia barraudi, S. indica, S. khawi and Idiophlebotomus asperulus but no Leishmania spp. DNA. Moreover, bloodmeal analysis revealed that Trypanopsoma-positive females of S. barraudi and Sergentomyia sp. fed on dogs and humans, respectively. The results of this study contribute to the knowledge of leishmaniasis and trypanosomiasis presence and sand fly feeding behavior in southern Thailand.

Abstract

An entomological survey at rural and cavernicolous localities in four provinces in southern Thailand provided 155 blood-fed females of sand flies (Diptera: Psychodidae) that were identified based on morphological characters as Idiophlebotomus asperulus (n = 19), Phlebotomus stantoni (n = 4), P. argentipes (n = 3), Sergentomyia anodontis (n = 20), S. barraudi (n = 9), S. hamidi (n = 23), S. hodgsoni (n = 4), S. hodgsoni hodgsoni (n = 32), S. indica (n = 5), S. iyengari (n = 2), S. khawi (n = 17), S. silvatica (n = 11) and Sergentomyia sp. (n = 6). The dominant species in this study was S. hodgsoni hodgsoni, which was collected specifically in a Buddha cave. Screening for DNA of parasitic protozoans revealed eight specimens (5.16%) of four species (S. barraudi, S. indica, S. khawi and Id. asperulus) positive for Trypanosoma sp., while no Leishmania spp. DNA was detected. Blood meals of engorged females were identified by PCR-Restriction Fragment Length Polymorphism (PCR-RFLP) assay on a fragment of cytochrome b (cyt b) gene with a success rate 36%, humans, dogs, and rats being determined as sources of blood. Bloodmeal analysis of two Trypanopsoma-positive females (S. barraudi and Sergentomyia sp.) identified blood from dogs and humans, respectively. Our findings indicate that S. barraudi, S. indica, S. khawi and Id. asperulus may be incriminated in circulation of detected Trypanosoma spp.

Host preference and Leishmania infantum natural infection of the sand fly Phlebotomus perfiliewi in northern Italy

The host preference of hematophagous insects is important in determining the cycle of pathogens that they potentially transmit; for example, sand flies are competent vectors of Leishmania parasites. In this work, we evaluated the host preference of sand flies collected in the Emilia-Romagna region of Italy in 2018 and 2019 in an area in which Leishmania infantum circulates actively. Out of about 30,000 sampled sand flies, we obtained 252 engorged females, which were processed to identify the sources of blood meals. Sampling data collected confirmed a positive phototropism of Phlebotomus (Ph.) perfiliewi respect to Ph. perniciosus and the enhanced efficiency of light traps in collecting engorged females compared with traps baited with carbon dioxide. We identified blood source in 185 females (183 Ph. perfiliewi, two Ph. pernicious). The most bitten animal was the roe deer (49.5%), followed by humans (29.2%), hare (7.1%) and cow (4.7%). Other animals, including wild boar, horse, donkey, porcupine, chicken and red fox, were less represented (<2%), while the blood of dogs and rodents were not detected. In addition, we singly screened engorged females for Leishmania founding 5 positive specimens, fed on roe deer (4) and man (1), providing evidence of parasite circulation in a sylvatic environment, where presence of dogs was not common. These findings suggest the existence of an uncharacterized Leishmania reservoir in the surveyed area.

Determination of sand fly fauna and molecular detection of Leishmania in sand flies in Antalya Province, Southern Turkey

Visceral leishmaniasis (VL) and cutaneous leishmaniasis (CL) are diseases transmitted by infected female sand flies. Since the eradication of malaria in Turkey, CL is the main vector-borne disease in the country, with more than 2000 cases per year, making it a significant public health problem. The aims of this study were to carry out an entomological survey in Antalya Province, an endemic area for CL in the Mediterranean Region of Turkey, to identify sand fly fauna and to screen female specimens for the presence of Leishmania parasites (Leishmania infantum, L. tropica, L. major, and L. donovani) using molecular analysis. Sand flies were collected in 42 localities of seven districts in Antalya Province using CDC miniature light traps in two different periods, June 2012 and September 2013. The specimens were kept in 96% ethanol until the dissection was done. The head and genitalia of the specimens were cut for preparing individual slides for species identification. The rest of the body of female specimens was kept separately. The specimens were identified at the species level, and 27 pools were generated according to the locations and species for screening the presence of Leishmania. A commercial kit was used for DNA extractions. Real-time and conventional polymerase chain reaction (PCR) targeting the internal transcribed spacer region (ITS1) were then performed. In total, 1306 specimens comprising nine species belonging to the Phlebotomus genus were collected in the study region, with Phlebotomus neglectus/syriacus (38.82%) the most abundant, followed by P. alexandri (21.67%) and P. tobbi (20.44%). In the 27 pools, Leishmania infantum DNA was detected in four pools containing P. neglectus/syriacus and one pool containing P. tobbi. In conclusion, the sand fly fauna in the Antalya Province is diverse. The probable vector sand fly species are P. neglectus/syriacus and P. tobbi with high dominance (59.26%), which indicates a high risk of CL transmission. The data presented here may help to shed more light on the transmission cycles of the Leishmania parasite in this CL endemic area.

Cutaneous Leishmaniasis in Pakistan: a neglected disease needing one health strategy

Background

Cutaneous Leishmaniasis (CL) is a neglected tropical disease, which mainly affects poor communities. It is one of the major vector-borne disease and endemic in Pakistan.

Methods

A case-control study to evaluate potential risk factors of human-CL was conducted in Khewra region, District Jhelum, Pakistan from January–April 2014. Case data about 90 cases registered during October 2012 to November 2013 was retrieved from Municipal Hospital. Controls were matched (1,1 ratio) on the date of registration with cases from same hospital. Both cases and controls were invited to participate and data was collected in a face-to-face interview. A prospective study of canine leishmaniasis (canine-CL) was also conducted at Civil Veterinary Hospital in the same area. Suspected dogs with skin ulceration signs were included in the study and blood samples were collected. Statistical analyses were conducted to determine association between various parameters and outcome of interest.

Results

The ages of cases ranged from 1 to 76 years (median = 15 years) and proved to be protective factor i.e. increase in each year in age reduced the likelihood of being infected with human-CL [Odds Ratio (OR) = 0.4, 95% Confidence Interval (CI) = 0.25–0.76]. People sleeping outsides in an open area were more likely to become a case (OR = 8.7, 95% CI = 2.90–26.37) than a control. Poor sanitary condition inside the house (OR = 3.3, 95% CI 1.03–10.56) and presence of other animals in house (livestock, poultry) (OR = 3.6, 95% CI = 1.07–12.12) also identified as risk factors of high significance. The proportion of positive dogs with canine-CL was 21.05% and was significantly associated with human-CL cases in the same area (p < 0.05).

Conclusions

We concluded that adopting self-protections measures against sand-fly, and maintaining good hygiene may lower the risk of human-CL. One-Health Strategy is suggested to control leishmaniasis in human and dog population.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-06327-w.

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.

Opportunistic feeding behaviour and Leishmania infantum detection in Phlebotomus perniciosus females collected in the human leishmaniasis focus of Madrid, Spain (2012-2018)

Background

An outbreak of human leishmaniasis due to Leishmania infantum has been registered in an urban area of southwestern Madrid, Spain, since 2010. Entomological surveys carried out in the municipalities of Fuenlabrada, Leganés, Getafe and Humanes de Madrid showed that Phlebotomus perniciosus is the only potential vector. In this work, an intensive molecular surveillance was performed in P. perniciosus females captured in the region between 2012 and 2018.

Methodology/Principal findings

A total of 1805 P. perniciosus females were analyzed for Leishmania infection, and 1189 of them also for bloodmeal identification. Eleven different species of vertebrate were detected by amplification and subsequent sequencing of the 359 bp cytb fragment. The most prevalent blood source identified was hare (n = 553, 46.51%), followed by rabbit (n = 262, 21.95%). Less frequent were cat (n = 45, 3.80%), human (n = 34, 2.90%), pig (n = 14, 1.20%), horse (n = 11, 0.93%), sheep (n = 3, 0.25%), rhea (n = 3, 0.25%), partridge (n = 1, 0.09%) and chicken (n = 1, 0.09%). The distribution of the blood meal sources varied between the different locations. Regarding L. infantum detection, PCR amplification of a fragment of kDNA, cpb gene and ITS1 region showed 162 positive specimens (8.97%). The highest infection rate was found in the municipality of Leganés (15.17%).

Conclusions

The results of this molecular survey in P. perniciosus, the only leishmaniasis vector in the outbreak occurred in southwestern Madrid region, showed its opportunistic blood-feeding behaviour, high infection rates and the differences between the different points. This study was an essential part of the intensive surveillance plan in the area and the results obtained have supported the implementation of control measures in the outbreak.

Vector-borne diseases (VBD) comprise a pathogen-vector-reservoir relation, and control programs should take into account different factors involving this relationship. This study is focused on a leishmaniasis outbreak that has occurred in the southwestern Madrid region since 2010. An intensive molecular surveillance of the sand fly vector Phlebotomus perniciosus was carried out from 2012 to 2018 in 4 municipalities from the affected region: Fuenlabrada, Leganés, Getafe and Humanes de Madrid. The aim of this investigation was to discern how much the vector was infected and find out its blood-feeding habits in the different surveyed points. The results showed an important rate of infected sand flies and also that P. perniciosus presents an opportunistic blood-feeding behaviour, taking blood from many different hosts, depending on their availability and density. The results obtained in this surveillance helped the authorities to plan and implement more accurate and effective control measures in the area, reflecting the importance of applying molecular surveillance in VBD outbreaks.

The initial detection of Toscana virus in phlebotomine sandflies from Turkey

Toscana virus (TOSV) is a prominent arthropod-borne viral agent of human central nervous system infections occurring in the Mediterranean region. The main transmission route to susceptible individuals involves sandflies as vectors. Despite several reports revealing widespread TOSV activity in Turkey, vectors remained unidentified. A sandfly field survey was carried out in five provinces in Central, Southeast and Mediterranean Anatolia in 2017 to identify TOSV and related sandfly-borne phleboviruses and Leishmania parasites, with evidence for circulation in the region. A total of 7136 sandfly specimens, collected via standard methods, were evaluated in 163 pools. TOSV was detected in 11 pools (6.7%), comprising Phlebotomus major sensu lato, Sergentomyia dentata and Phlebotomus papatasi species. TOSV partial L and S segment sequences were characterized, that phylogenetically clustered with local and global genotype A strains. An amino acid substitution outside the conserved motifs of the viral polymerase, also present in previous TOSV sequences in endemic regions, was observed. Leishmania tropica was detected in a single pool of Ph. sergentii (0.6%). This is the first report of TOSV in sandflies from Turkey, and this study further provides evidence for additional sandfly species with the potential to transmit TOSV.

Cutaneous Leishmaniasis due to Three Leishmania Species Among Syrian Refugees in Sanliurfa, Southeastern Turkey

Sanliurfa, a city in southeastern Turkey, is host to 477,166 Syrian refugees. The incidence of cutaneous leishmaniasis (CL) may be on the rise in areas affected by a refugee crisis, like Sanliurfa; thus, consequently, local uncommon species of Leishmania may be encountered in these regions. This might potentially make diagnosis and treatment more challenging over time. In this study, it was aimed to identify the causative agents of CL in clinical samples. A total of 154 patients (60 Syrian and 94 Turkish) who were diagnosed with CL via microscopical examination and PCR were enrolled this study. All of the samples were analyzed using internal transcribed spacer 1 genes, restriction fragment length polymorphism, DNA-sequencing, and phylogenetic analyses. In this study, Leishmania tropica was determined to be the predominant species in 140 of the patients (90.9%), followed by Leishmania major in 12 patients (7.8%), and Leishmania infantum in 2 patients (1.3%). Of the 94 Turkish patients, 94.7% were infected with L. tropica and 5.3% were infected with L. major, while none were infected with L. infantum. However, of the 60 Syrian patients, 85% were infected with L. tropica, 11.7% were infected with L. major, and 3.3% were infected with L. infantum. There was a significant association between the Leishmania species and the nations (Turkish-Syrian) (P < 0.001). The sequences were numbered from MH347941 to MH347953 and submitted to GenBank. This study confirmed that L. tropica, L. major, and L. infantum coexisted in Sanliurfa. This was the first time that the species L. infantum was reported among recent immigrants from Syria in Sanliurfa. Therefore, it is necessary to discriminate the Leishmania species for diagnosis, treatment, and controlled studies in hyper-endemic regions.

First Serological Study Revealing High Humoral Response and Evidence for Antigenic Heterogeneity in Leishmania donovani Induced CL in Sri Lanka

Posing a threat to the ongoing leishmaniasis elimination efforts in the Indian subcontinent, L. donovani-induced cutaneous leishmaniasis (CL) has been recently reported in many countries. Sri Lanka reports a large focus of human cutaneous leishmaniasis (CL) caused by Leishmania donovani, a usually visceralizing parasite. Enhanced case detection, early treatment, and in-depth understanding of sequalae are required to contain the spread of disease. Visceralizing potential of dermotropic strains has not been fully ruled out. Sri Lankan strains have shown a poor response to established serological assays. The present concern was to develop an in-house serological assay and to determine the seroprevalence of CL for identifying visceralizing potential and its usefulness in enhancing case detection. Crude cell lysate of dermotropic L. donovani promastigotes-based indirect enzyme-linked immunosorbent assay (ELISA) was previously optimized. Assay was evaluated using sera from 200 CL patients, 50 endemic and 50 nonendemic healthy controls, 50 patients with other skin diseases, and 50 patients with other systemic diseases. Seroprevalence and clinicoepidemiological associations were analyzed. Assay was compared with light microscopy (LM) and in vitro culturing (IVC). Cost comparison was carried out. Seroprevalence of CL was 82.0%. The assay had 99.5% specificity, and all healthy controls were negative at 0.189 cut-off. Positive and negative predictive values were 99.4% and 84.7%, respectively. Positivity obtained in ELISA was comparable to LM and higher than that of IVC. Cost per patient was 3.0 USD for both ELISA and LM and 6.0 USD for IVC. Infections occurring in all age groups and both genders demonstrated >75.0% of seropositivity. Patients had lesions with different durations/types/sizes showed >70.0% of seropositivity. Study identified a high seroprevalence of L. donovani-induced CL for the first time, indicating potential for visceralization or transient serological response. This can be used as a second line test in LM-negative CL cases to enhance clinical case detection. Further studies are warranted to examine in-depth correlations, antigen profiles, comparison with other established serological tools, and usefulness in the detection of asymptomatic cases. (National patent LK/P/1/19697).

Entomological Survey for the Detection of Sand Fly Fauna and Vector Species in the Cutaneous Leishmaniasis Endemic Area in East Mediterranean Region of Turkey, Mersin Province

Cutaneous (CL) and visceral (VL) forms of leishmaniasis, transmitted by sand flies, are seen in all countries located in Mediterranean Basin including Turkey. In this study, we aimed to conduct an entomological survey for the detection of sand fly fauna and vector species in Mersin province, one of the important endemic areas for CL in Turkey. In total, 912 sand fly specimens were collected in 2010 and 2011 using CDC light traps. Nine Phlebotomus (Diptera: Psychodidae) and three Sergentomyia (Diptera: Psychodidae) species were detected. Of the collected Phlebotomus sand flies, P. sergenti Parrot, 1917 (30.1%) was the most dominant followed by P. alexandri Sinton, 1928 (18.2%), P. neglectus/syriacus Tonnoir Adler (12.0%), P. tobbi Adler & Theodor, 1930 (11.7%), and P. papatasi Scopoli, 1786 (10.2%), while S. minuta Rondani, 1843 (11.3%) was the dominant species among Sergentomyia. During the field work in 2011, female specimens (n = 81) were screened for the presence of Leishmania promastigotes by midgut dissection, and all were found negative. The rest of the collected female specimens (n = 334) were pooled according to species (P. alexandri, P. neglectus/syriacus, P. papatasi, P. sergenti, P. simici, and P. tobbi) and location (Mut, Silifke, and Anamur). In total, 29 pools were generated and real-time ITS1 PCR assay was performed to detect and identify natural Leishmania Ross, 1903 (Kinetoplastida: Trypanosomatida) infection. Two pools, both from Mut town, containing P. sergenti specimens were found positive and Leishmania tropica Ross, 1903 was identified as an infectious agent for both pools. In conclusion, the sand fly fauna was determined in an endemic area for CL. The detection of L. tropica DNA in P. sergenti specimens showed the possible vectorial role of this species in Mersin province.

Prevalidation of an ELISA for Detection of a New Clinical Entity: Leishmania donovani-Induced Cutaneous Leishmaniasis

Human leishmaniasis which is considered a neglected tropical parasitic disease presents in three main clinical forms (i.e., cutaneous leishmaniasis (CL), mucocutaneous leishmaniasis (MCL), and visceral leishmaniasis (VL)) that are mainly determined by its causative species. Leishmania donovani, the most virulent and visceralizing parasite, is increasingly reported to cause CL in many countries in the world. Although CL is generally not considered to evoke a humoral immune response except for a nonrobust and a variable response in minority of cases, VL is associated with a clear strong humoral response. However, humoral response in L. donovani-induced CL has not been well evaluated before. A suitable serology-based assay is an essential primary step in such a study. An indirect enzyme-linked immunosorbent assay (ELISA) based on Leishmania promastigote crude antigen (Ag) was designed and optimized in order to utilize in further serological studies on this new clinical entity. Optimization included quantification of crude Ag, checkerboard titration method for determination of optimal concentrations for coating Ag, human sera and secondary antibody (Ab) with suitable coating buffer, blocking buffer, and incubating temperatures. The selected coating buffer was 0.02 M phosphate buffer, pH 6.8, and the blocking buffer was 2% fetal bovine serum with 0.01 M phosphate-buffered saline. At least 1 μg of crude Ag was required for coating the ELISA plate, while 1 : 1000 serum was used as primary Ab. The optimized concentration of secondary Ab was 1 : 64000 which might be altered according to manufacturer recommendations. The assay specificity was pre-evaluated using sera (n = 20 from each category) from confirmed CL patients and controls (other skin diseases which mimic CL, other systemic diseases that mimic VL, nonendemic healthy controls, and endemic healthy controls). This procedure described an optimization procedure of an ELISA technique for detection of anti-Leishmania antibodies in patients with L. donovani caused CL.

A spatial ecology study in a high-diversity host community to understand blood-feeding behaviour in Phlebotomus sandfly vectors of Leishmania

Molecular studies indicate that Phlebotomine sandflies (Diptera: Psychodidae) blood feed on many vertebrate species, of which only a few are proven parasite reservoirs. Investigating sandfly vector feeding preferences is therefore important and requires taking into account the availability and accessibility of host species. In terms of the latter, it is necessary to consider the metabolic cost to the insect of reaching the host and moving on to a suitable breeding site. The present study used statistical modelling to compare the feeding patterns of Phlebotomus perniciosus (n = 150), Phlebotomus papatasi (n = 35) and Phlebotomus ariasi (n = 7) on each of an average of 30 host species in a wildlife park in Murcia, Spain. Sandfly feeding movement costs were estimated as a function of the distance and altitude gradients saved by the insect, assuming that they displayed 'site fidelity'. Most (87%) engorged females were caught <100 m from the host on which they had fed. Although the percentage of bloodmeals was highest on fallow deer (Dama dama) (30%) and red deer (Cervus elaphus) (26%), the predicted feeding probability after considering movement cost was highest for red deer and common eland (Taurotragus oryx), and positively associated with host census. These results suggest that, under similar circumstances, sandflies prefer to feed on some host species more than on others.

Leishmania infection in cats and dogs housed together in an animal shelter reveals a higher parasite load in infected dogs despite a greater seroprevalence among cats

Background

An outbreak of leishmaniosis was studied in cats and dogs housed together with no separation in an animal shelter in Israel.

Methods

The study included recording of clinical signs, serology for Leishmania infection by ELISA, PCR of blood for Leishmania DNA by ITS1 HRM and kDNA PCR, parasite quantification, and trapping of sand flies around the shelter.

Results

Thirty-seven % (22/60) of the dogs and 75% (50/67) of the cats were seropositive to L. infantum with a significantly higher seropositivity rate in the cat population (χ² = 42.160, P < 0.0001). Twenty-five percent (15/60) of the dogs were positive for Leishmania by blood PCR, 12% by the Leishmania ITS1 HRM PCR and 22% by kDNA PCR. Of the cats, 16% (11/67) were positive by kDNA PCR and none by ITS1 HRM PCR. All the PCR-positive animals were infected by L. infantum verified by DNA sequencing and there was no significant difference between the PCR-positivity in the dog and cat populations. Altogether, 43% (26/60) of the dogs and 79% (53/67) of the cats were positive by serology or PCR for L. infantum. The average Leishmania parasite load in the blood of PCR-positive dogs (42,967 parasites/ml) was significantly higher than in PCR-positive cats (1259 parasites/ml) (t₍₁₂₎ = 2.33, P = 0.037). Dogs that were positive by the Leishmania ITS1 HRM PCR and kDNA PCR had significantly higher parasite loads than dogs positive only by the kDNA PCR (t₍₁₁₎ = − 3.186580, P < 0.009). No significant effect was found for FIV seropositivity on Leishmania infection in the cats (χ² = 0.506, P = 0.777). A higher percentage of Leishmania-positive dogs showed clinical signs compatible with leishmaniosis compared to Leishmania-positive cats (100 vs 52.8%, χ² =15.242, P < 0.0001). Phlebotomus perfiliewi, a proven vector of L. infantum, comprised 92% of trapped sand flies.

Conclusions

Comparisons of populations of cats and dogs exposed to sand flies and L. infantum under the same conditions indicated that although a high rate of exposure was detected in cats as manifested by a significantly greater degree of seropositivity, dogs had significantly higher blood parasite loads, and were likely to be more infectious to sand flies than cats.

Identification of trypanosomatids and blood feeding preferences of phlebotomine sand fly species common in Sicily, Southern Italy

In this study, the presence of Leishmania DNA and blood feeding sources in phlebotomine sand fly species commonly present in Sicily were investigated. A total of 1,866 female sand flies including 176 blood fed specimens were sampled over two seasons in five selected sites in Sicily (southern Italy). Sergentomyia minuta (n = 1,264) and Phlebotomus perniciousus (n = 594) were the most abundant species at all the sites, while three other species from the genus Phlebotomus (i.e., P. sergenti n = 4, P. perfiliewi n = 3 and P. neglectus n = 1) were only sporadically captured. Twenty-eight out of the 1,866 (1.5%) sand flies tested positive for Leishmania spp. Leishmania tarentolae DNA was identified in 26 specimens of S. minuta, while the DNA of Leishmania donovani complex was detected in a single specimen each of S. minuta and P. perniciosus. Interestingly, seven S. minuta specimens (0.4%) tested positive for reptilian Trypanosoma sp. Blood sources were successfully identified in 108 out of 176 blood fed females. Twenty-seven out of 82 blood sources identified in fed females of P. perniciosus were represented by blood of wild rabbit, S. minuta mainly fed on humans (16/25), while the sole P. sergenti fed specimen took a blood meal on rat. Other vertebrate hosts including horse, goat, pig, dog, chicken, cow, cat and donkey were recognized as blood sources for P. perniciosus and S. minuta, and, surprisingly, no reptilian blood was identified in blood-fed S. minuta specimens. Results of this study agree with the well-known role of P. perniciosus as vector of L. infantum in the western Mediterranean; also, vector feeding preferences herein described support the hypothesis on the involvement of lagomorphs as sylvatic reservoirs of Leishmania. The detection of L. donovani complex in S. minuta, together with the anthropophilic feeding-behaviour herein observed, warrants further research to clarify the capacity of this species in the transmission of pathogens to humans and other animals.

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.

A survey of sand flies (Diptera, Phlebotominae) along recurrent transit routes in Serbia

Serbia was a country endemic for leishmaniasis with rich and abundant sand fly fauna during the middle of the 20^th century. After 1968, the disease was considered as eradicated, and as a consequence, all research on vectors and pathogens was neglected. The recent detection of Leishmania infantum in sand flies and confirmed cases of leishmaniasis in humans and dogs indicated the risk of re-emergence in Serbia. Also, for millions of refugees/immigrants, Serbia is a transit route between East-Mediterranean and Middle-East countries, and Central/North Europe, and it is under constant risk of vector and disease introduction. Primary objectives of this research were to determine which sand fly species are present around transit routes, whether they include vectors of the Leishmania spp. moreover, is/are Leishmania spp. present in the vectors. Surveys were conducted at 55 locations, organised in four clusters, which covered main immigrant routes and shelters/camps as well as tourist/trade transit routes. In total, 367 sand fly specimens were collected. Nine species were identified: Phlebotomus papatasi, P. perfiliewi, P. tobbi, P. neglectus, P. sergenti, P. alexandri, P. simici, P. balcanicus and P. mascittii. Detection of P. alexandri represents the first record in Serbia. The diversity of sand fly species increased while the number of collected specimens per night decreased during the period of research neglection. Phlebotomus neglectus, a proven vector of L. infantum, was a predominant species in all surveyed clusters, and in 56,52% of locations, it was the only species present. Although all detected species are regarded either as proven or suspected vectors of Leishmania spp., screening of females for Leishmania presence resulted negative. Our study provides insight into the significant changes of sand fly fauna in Serbia during the end of XX and beginning of XXI century. Diverse sand fly fauna in Serbia suggests that the establishment of new leishmaniasis foci is possible.

Demographical and population dynamics impact on public health of cutaneous Leishmaniasis in Al-Madinah Almonawra, Saudi Arabia

Background

A cross-sectional study conducted in Al-Madinah Almonawra in KSA held during the period from March 2014–March 2015.

Aim of the study

This study aimed at analyzing the effect of population dynamics on the current situation of cutaneous leishmaniasis in Al-Madinah Almonawarah area, a holy city that attracts millions of muslims annually.

Methodology

Epidemiological and clinical data were collected by especial questionnaire and laboratory specimens were collected using skin scraping and needle aspiration. Staining and direct microscopy were done. LST was conducted. Analysis was done using SPSS program.

Results

The study included 164 patients, all of them were men. Saudi nationality comprised around 20% of the study group, the majority were Egyptians, 26.2%, followed by Pakistani, 21.3%.

Conclusion

The presence of non-Saudi nationality as foreign workers, immigrants and refugees has worsened the current situation of the disease.

Revision of the species composition and distribution of Turkish sand flies using DNA barcodes

Background

Currently, knowledge regarding the phlebotomine sand fly (Diptera: Psychodidae) fauna of Turkey is restricted to regions with endemic leishmaniasis. However, rapidly changing environmental and social conditions highlight concerns on the possible future expansion of sand fly-borne diseases in Turkey, promoting risk assessment through biosurveillance activities in non-endemic regions. Traditional morphological approaches are complicated by extensive cryptic speciation in sand flies, thus integrated studies utilizing DNA markers are becoming increasingly important for correct sand fly identification. This study contributes to the knowledge of the sand fly fauna in understudied regions of Turkey, and provides an extensive DNA barcode reference library of expertly identified Turkish sand fly species for the first time.

Methods

Fly sampling was conducted at 101 locations from 29 provinces, covering all three biogeographical regions of Turkey. Specimens were morphologically identified using available keys. Cytochrome c oxidase I (cox1) barcode sequences were analyzed both for morphologically distinct species and those specimens with cryptic identity. A taxon identity tree was obtained using Neighbor Joining (NJ) analysis. Species boundaries among closely related taxa evaluated using ABGD, Maximum Likelihood (ML) and haplotype network analyses. Sand fly richness of all three biogeographical regions were compared using nonparametric species richness estimators.

Results

A total of 729 barcode sequences (including representatives of all previously reported subgenera) were obtained from a total of 9642 sand fly specimens collected in Turkey. Specimens belonging to the same species or species complex clustered together in the NJ tree, regardless of their geographical origin. The species delimitation methods revealed the existence of 33 MOTUs, increasing the previously reported 28 recorded sand fly species by 17.8%. The richest sand fly diversity was determined in Anatolia, followed by the Mediterranean, and then the Black Sea regions of the country.

Conclusions

A comprehensive cox1 reference library is provided for the sand fly species of Turkey, including the proposed novel taxa discovered herein. Our results have epidemiological significance exposing extensive distributions of proven and suspected sand fly vectors in Turkey, including those areas currently regarded as non-endemic for sand fly-borne disease.

Electronic supplementary material

The online version of this article (10.1186/s13071-019-3669-3) contains supplementary material, which is available to authorized users.

The changing distribution of Leishmania infantum Nicolle, 1908 and its Mediterranean sandfly vectors in the last 140 kys

The understanding of the effects of past climatic changes on the distribution of vector arthropods can strongly support the understanding of the future potential impact of anthropogenic climatic change on the geographical risk of vector-borne diseases. The zoogeographical patterns of the European sandfly vectors may suffer the continuously changing climate of the last 140 kys. The former range of L. infantum and six Phlebotomus species were modelled for the Last Interglacial, the Last Glacial Maximum and the Mid-Holocene Periods. It was found that the potential distribution of the parasite was much smaller in the Last Glacial Period L. infantum mainly could persist in the western shelves of the Mediterranean Sea. West and East Mediterranean sandfly species inhabited partly distinct refugia. The Apennine Peninsula, Sicily and the Iberian refugium formed a habitat chain along with the coastal areas of the West Mediterranean Basin. There was no direct connection between the Eastern and the Western sandfly refugia in the last 140 kys. The modelled distribution of sandfly taxa for the Middle Holocene Period can explain the relict populations of sandfly taxa in such Central European countries. The former genetic studies strongly confirm the existence of the modelled glacial refugees.

Experimental infection of Phlebotomus perniciosus and Phlebotomus tobbi with different Leishmania tropica strains

Cutaneous leishmaniasis due to Leishmania tropica is increasingly documented in Europe and the Middle East. Besides its specific vector, Phlebotomus sergenti, permissive Phlebotomus sand flies are suspected as potential vectors of L. tropica. We investigated the susceptibility of two widely distributed species, Phlebotomus perniciosus and Phlebotomus tobbi. Laboratory-reared sand flies were infected experimentally with L. tropica strains differing in lipophosphoglycan epitopes, geographical distribution and epidemiology. High infection rates, heavy parasite loads and fully developed late-stage infections including colonization of the stomodeal valve were observed in all parasite-vector combinations. Our findings demonstrate that P. perniciosus and P. tobbi are susceptible to different L. tropica strains and may play a role in their circulation in endemic foci of Europe, the Middle East and North Africa.

Leishmaniasis in Istanbul; A new epidemiological data about refugee leishmaniasis

Leishmania is an intracellular parasite, which is transmitted by the bite of infected female Phlebotominae sand flies. Turkey is a crossroad between Europe and Asia that makes it important in terms of epidemiology. In the present study, we aimed to evaluate Leishmania infection among non-autochthonous patients admitted to Health Sciences University, Dr. Sadi Konuk Research and Training hospital between 2014-2018. Slides were prepared by sampling the edge of the lesions for each patient. Microscopical examination was performed after staining procedures. After microscopical examination slides were washed and DNA extraction was performed. ITS-1 real-time PCR was performed to identify the species of the causative agents. Demographic data were recorded for each patient. Also number, type and location of the lesions were recorded. Totally 13 patients were included in this. Majority (12/13) of them were found to be infected with L. tropica, while one patient was infected with L. infantum. Two of the lesions were wet type and 11 of them were dry type lesions. Several papers were published recently about leishmaniasis in Turkey but to best of our knowledge, this is the first study reporting refugee leishmaniasis in İstanbul.

Leishmaniasis in Eurasia and Africa: geographical distribution of vector species and pathogens

Leishmaniasis is a vector-borne disease with a broad global occurrence and an increasing number of recorded cases; however, it is still one of the world's most neglected diseases. We here provide climatic suitability maps generated by means of an ecological niche modelling approach for 32 Phlebotomus vector species with proven or suspected vector competence for five Leishmania pathogens occurring in Eurasia and Africa. A GIS-based spatial overlay analysis was then used to compare the distributional patterns of vectors and pathogens to help evaluate the vector species-pathogen relationship currently found in the literature. Based on this single factor of vector incrimination, that is, co-occurrence of both vector and pathogen, most of the pathogens occurred with at least one of the associated vector species. In the case of L. donovani, only a not yet confirmed vector species, P. rodhaini, could explain the occurrence of the pathogen in regions of Africa. Phlebotomus alexandri and P. longiductus on the other hand, proven vector species of L. donovani, do not seem to qualify as vectors for the pathogen. Their distribution is restricted to northern latitudes and does not match the pathogen's distribution, which lies in southern latitudes. Other more locally confined mismatches were discussed for each pathogen species. The comparative geographical GIS-overlay of vector species and pathogens functions as a first indication that testing and re-evaluation of some pathogen-vector relationships might be worthwhile to improve risk assessments of leishmaniasis.

Modeling the Ecological Niche: A Case Study on Bioclimatic Factors Related to the Distribution of Phlebotomus tobbi Adler & Theodor (Diptera: Psychodidae) in Two Endemic Foci of Adana

Cutaneous leishmaniasis (CL) is a zoonotic infectious disease caused mainly by Leishmania infantum Nicolle, 1908 (Kinetoplastida: Trypanosomatida) transmitted by dominant species Phlebotomus tobbi Adler & Theodor (Diptera: Psychodidae) in Adana, Turkey. CL has been reported to be detected commonly in low-socioeconomic status population scattered in rural areas. The environmental determinants are relatively poorly understood, especially in Adana despite the fact that Adana is endemic foci of CL. The subject of this study was the current and future probability model of P. tobbi in the study areas, and to determine the underlying factors affecting its distribution. Sticky papers and CDC light traps were used for capturing the sand fly specimens. The current and future presence of P. tobbi was modeled using maximum entropy (MaxEnt) techniques. The predictive model indicated the presence of P. tobbi in the southeast and south part of the selected study area with 0.816 area under the curve (AUC) value. The model also implied that its survival could tend to expand with suitable climatic conditions in future (2070) with 0.798 AUC value. In addition, aspect, digital elevation model, BIO3, BIO 10, BIO12, and BIO14 were determined as the most influential variables for current and projected future. ArcGIS and MaxEnt software were used for the ecological niche model analysis to explore the ecological conditions of the disease. I suggest that produced models contribute to better understanding of epidemiology and controlling of vector-borne diseases.

A climate-driven and field data-assimilated population dynamics model of sand flies

Sand flies are responsible for the transmission of leishmaniasis, a neglected tropical disease claiming more than 50,000 lives annually. Leishmaniasis is an emerging health risk in tropical and Mediterranean countries as well as temperate regions in North America and Europe. There is an increasing demand for predicting population dynamics and spreading of sand flies to support management and control, yet phenotypic diversity and complex environmental dependence hamper model development. Here, we present the principles for developing predictive species-specific population dynamics models for important disease vectors. Based on these principles, we developed a sand fly population dynamics model with a generic structure where model parameters are inferred using a surveillance dataset collected from Greece and Cyprus. The model incorporates distinct life stages and explicit dependence on a carefully selected set of environmental variables. The model successfully replicates the observations and demonstrates high predictive capacity on the validation dataset from Turkey. The surveillance datasets inform about biological processes, even in the absence of laboratory experiments. Our findings suggest that the methodology can be applied to other vector species to predict abundance, control dispersion, and help to manage the global burden of vector-borne diseases.

Vector and reservoir surveillance study in a canine and human leishmaniasis endemic area in most western part of Turkey, Karaburun

Leishmaniasis is an arthropod borne disease that is endemic in 102 countries and one and half million new cases are reported each year. Sand flies are the one and only proven vectors of the disease and dogs are the main reservoirs in urban areas. Karaburun peninsula is located in most western part of Turkey and is reported to be an endemic area for human and canine leishmaniasis. The most recent study was undertaken more than 15 years ago in The peninsula and no clear data available for vectors or reservoirs. Thus, we aimed to update the information regarding sand fly diversity, infection status of reservoirs and vectors in the study area. Sand flies were collected using CDC light traps at 13 different sites of Karaburun and species identification was made using previously published keys. Monospecific pools were generated using midguts with blood retention and were screened for the presence of Leishmania spp. DNA by molecular techniques. A non-invasive conjunctival swab sampling was performed to identify the infection status among reservoirs and species typing of the causative agent was also undertaken using ITS1 PCR. Three out of 30 pools were found positive for Leishmania infantum that were generated using guts of Phlebotomus tobbi (n:36). Among all sampled dogs (44) and cats (19), 11 and one of them were found positive for L. infantum, respectively. There was a decrease in the number of P. papatasi during the study period, while increase was observed in the number of P. tobbi. The presence of proven vectors and reservoirs as well as Leishmania DNA in cats was shown in the present study. Sand fly fauna is updated and Leishmania DNA presence in cats was reported in the study area for the first time.

Complex Investigation of a Pediatric Haematological Case: Haemophagocytic Syndrome Associated with Visceral Leishmaniasis and Epstein⁻Barr (EBV) Co-Infection

BACKGROUND

Visceral leishmaniasis (VL) is an anthropozoonosis caused by an intracellular parasite belonging to the genus Leishmania. In the Mediterranean region, L. donovani and L. infantum are responsible for VL and dogs are the main reservoir. Haemophagocytic lymphohistiocytosis (HLH) represents a complication of VL and consists of unrestrained activation and proliferation of lymphocytes and macrophages, leading to uncontrolled immune activation. Haemophagocytic lymphohistiocytosis may also develop during viral infection, and Epstein⁻Barr virus (EBV) infection is one of the main HLH causes. Macrophage haemophagocytosis in the bone marrow aspirate is pathognomonic.

CASE PRESENTATION

The case involves a 19-month-old male infant presenting with a high persistent fever with a fluctuating pattern, pancytopaenia, hepatosplenomegaly, and a high triglyceride level. Initial investigations showed an EBV infection. Considering the persistent signs and symptoms, bone marrow aspiration was performed and confirmed the suspicion of HLH. In addition, the presence of Leishmania infection was shown. The patient was treated with liposomal amphotericin B and had complete resolution of his symptoms.

CONCLUSION

Diagnosis of VL represents a demanding challenge in endemic and non-endemic areas. Our case demonstrates that leishmaniasis should always be considered in the differential diagnosis in patients presenting with hepatosplenomegaly and cytopaenia with a persistent fever, even in cases of infectious mononucleosis. Moreover, the execution of bone marrow aspiration should not be delayed in order to diagnose and treat at an early stage the potential occurrence of VL, especially if complicated with HLH.

Population Structure of Leishmania tropica Causing Anthroponotic Cutaneous Leishmaniasis in Southern Iran by PCR-RFLP of Kinetoplastid DNA

Iran is one of the six countries with the most cutaneous leishmaniasis (CL) patients. Understanding better the genotypes of the parasite population in relation to geography and climate is critical to achieving better CL control. We aimed to characterise the population structure of Leishmania tropica, the cause of anthroponotic cutaneous leishmaniasis (ACL), from important foci in southeast (Bam and Kerman) and southwest (Shiraz) Iran. A total of 39 L. tropica isolates from ACL patients from southeast (Bam 14, Kerman 12) and southwest (Shiraz 13) Iran were analysed by polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) of the kinetoplast DNA (kDNA) using restriction enzymes MspI (HpaII) and ClaI. 37 genotypes were identified among south Iran L. tropica isolates. The unweighted pair group method with arithmetic mean (UPGMA) tree obtained from the banding patterns of ClaI digested kDNA RFLP distinguished southeast from and southwest L. tropica isolates with some subclustering but the MspI derived tree showed greater discrimination with greater subclustering and divergence of the two foci of southeast region but with some overlapping. Although a monophyletic structure has been defined for southeast L. tropica, isolates from two foci of southeast Iran were partly discriminated in the current study.

Phlebotomus halepensis (Diptera: Psychodidae) Vectorial Capacity in Afyon and Nigde Province, Turkey

Leishmaniasis is a one of the vector-borne diseases and has two clinical forms in Turkey: cutaneous and visceral. The aim of this study was to determine the sand fly fauna in Afyon and Nigde provinces where endemic foci of cutaneous leishmaniasis (CL) in Turkey. In Afyon, 2,259 sand flies were collected in 73 locations in August 2009 and August 2010, using CDC light traps. In total, eight Phlebotomus species were identified; Phlebotomus halepensis (47.41%), Phlebotomus papatasi (31.42%), Phlebotomus neglectus/syriacus (9.38%), Phlebotomus balcanicus (7.48%), Phlebotomus simici (2.12%), Phlebotomus perfiliewi (1.90%), Phlebotomus sergenti (0.08%), Phlebotomus similis (0.13%), and Sergentomyia dentata (0.04%). A total of 418 sand fly specimens were caught by CDC light traps in 40 stations in Nigde in September 2009 and September 2010. In total, seven Phlebotomus species were identified; P. halepensis (74.16%), P. simici (13.87%), P. papatasi (3.82%), P. neglectus/syriacus (2.87%), P. balcanicus (2.63%), P. sergenti (2.39%), and Phlebotomus tobbi (0.23%). Collected sand flies were examined by microscope, and no promastigotes were found in their midguts. We categorized and pooled female specimens (1,031 females, 73 pools of 2-33 individuals). Leishmania species-specific ITS1 real-time PCR assay was performed for detection and identification of parasites. We detected 6 of the 73 pools with Leishmania tropica (Ross, 1903), (Trypanosomatidae). In conclusion, P. halepensis was found to be dominant species in both areas. We are in opinion that our findings support P. halepensis vectorial role for L. tropica in nature and it could be responsible for the transmission of L. tropica in these endemic areas.

Phlebotomine sand flies (Diptera: Psychodidae) in the Greek Aegean Islands: ecological approaches

BACKGROUND

Blood-sucking phlebotomine sand flies are the vectors of the protozoan parasites Leishmania spp. Different Phlebotomus species transmit different Leishmania species causing leishmaniases which are neglected diseases emerging/reemerging in new regions. Thirteen sand fly species, ten belonging to the medically important genus Phlebotomus and three belonging to Sergentomyia are known in Greece. An increasing number of human and dog cases are reported each year from all parts of the country including the Aegean Islands. However, no previous study has been conducted on the sand fly fauna on the islands, except for Rhodes and Samos. The aim of this study was to investigate sand fly species in eleven small Aegean islands; to understand species-specific relationships with environmental and climatic factors and to compare sand fly community parameters among islands. A risk analysis was carried out for each species using climatic and environmental variables.

RESULTS

Nine sand fly species: Phlebotomus neglectus, P. tobbi, P. similis, P. simici, P. perfiliewi, P. alexandri, P. papatasi, Sergentomyia minuta and S. dentata, were collected from the islands studied. Phlebotomus (Adlerius) sp. and Sergentomyia sp. specimens were also collected but not identified to the species level. There was a positive effect of distance from the sea on the abundance of P. neglectus, S. minuta and S. dentata, and a negative effect on the abundance of P. tobbi, P. simici and P. similis. In general, temperature preferences of sand fly populations were between 21 and 29 °C. Nevertheless, there were significant differences in terms of temperature and relative humidity preference ranges among species. The most important species found, P. neglectus, was indisputably the most adapted species in the study area with a very high reaction norm, favoring even the lower temperature and humidity ranges. Overall, the sand fly fauna in the islands was very rich but there were differences in species diversity, as indicated by the values of the Shannon-Wiener index, along with evenness and richness of the sand fly fauna between the islands and altitude ranges in the islands.

CONCLUSIONS

The study indicated that the Greek Aegean Islands, however small, maintain a rich sand fly fauna. This includes important vectors of Leishmania spp. representing a risk for parasite transmission to humans and dogs along with the danger of maintaining new Leishmania spp. if introduced to the area.

Evidence for Seroprevalence in Human Localized Cutaneous Leishmaniasis Caused by Leishmania donovani in Sri Lanka

Visceral leishmaniasis (VL) is considered as a major health threat in the Indian subcontinent. Leishmania donovani, a usually visceralizing species, causes cutaneous leishmaniasis (CL) in Sri Lanka. However, visceralizing potential of the local L. donovani is not yet fully understood. This project studied the seroprevalence of local CL by using an in-house ELISA. An IgG-based ELISA using crude Leishmania antigen (Ag) was developed and validated. A total of 50 laboratory confirmed cases of locally acquired CL were examined using the newly developed ELISA. According to the optimized ELISA, seroprevalence of anti-Leishmania IgG antibodies in the study group was 34.0% (n = 17/50). Majority of seropositive individuals were males (n = 13/17), representing 76%. Nearly half of the seropositive individuals were young adults (20–40 years, n = 9/17, 53%). Higher proportions of single lesions, large lesions, and nodular lesions were associated with a seroconversion. A proportion of local L. donovani infections leading to CL have the ability to raise an antibody response in the host. This may indicate early systemic involvement as one possibility. Study of a large number of patients with adequate follow-up would be useful.

Wing morphology variations in a natural population of Phlebotomus tobbi Adler and Theodor 1930

Cutaneous leishmaniasis (CL) is highly endemic in the Cukurova region, located on the crossroads of main refugee routes from the Middle East to Europe on the eastern Mediterranean part of Turkey. Our purpose was to investigate the phenotypic variation of Phlebotomus tobbi, the known vector of CL in the region, during one active season. Sand flies and microclimatic data were collected monthly from May to October, 2011, from five locations in six villages in the study area. A geometric morphometric approach was used to investigate wing morphology. Shape analyses revealed that males collected in May and June comprised one group, while specimens collected in August, September, and October formed a second group. Specimens from July were found to be distributed within these two groups. A similar distribution pattern was observed for females, but specimens from October were represented as the third district group. Significant size variation was detected for both sexes between months. Wing size and temperature were negatively correlated for females, but there was no temperature effect for males. Wing size of both sexes was increased in correlation to increasing relative humidity. Males were found to have smaller wings with increasing population density.

Dermotropic Leishmania donovani in Sri Lanka: visceralizing potential in clinical and preclinical studies

The visceralizing potential of apparently dermotropic Leishmania donovani in Sri Lanka (L. donovani-SL) was investigated through long-term follow-up of cutaneous leishmaniasis (CL) patients and in vivo and in vitro experimental infection models. CL patients (n = 250) treated effectively with intra-lesional antimony therapy were followed-up six monthly for 4 years. There was no clinical evidence of visceralization of infection (VL) during this period. Infection of BALB/c mice with L. donovani-SL (test) through intra-dermal route led to the development of cutaneous lesions at the site of inoculation with no signs of systemic dissemination, in contrast to the observations made in animals similarly infected with a visceralizing strain of L. donovani-1S (control). Cytokine (IL-10, IFN-γ) release patterns of splenocytes and lymph node cell cultures derived from mice primed with experimental infections (with either test or control parasites) revealed significantly high IFN-γ response associated with test mice with CL, while prominent IL-10 levels were observed in association with control mice with VL. Furthermore, diminished infection efficiency, intracellular growth and survival of L. donovani-SL parasites compared with L. donovani-1S were evident through in vitro macrophage infection experiments. These studies confirm, for the first time, the essential dermotropic nature of L. donovani-SL suggesting natural attenuation of virulence of local parasite strains.

Geographical Information Systems in Determination of Cutaneous Leishmaniasis Spatial Risk Level Based on Distribution of Vector Species in Imamoglu Province, Adana

The Imamoglu district located in the southeast of Adana province in Turkey is an endemic focus of cutaneous leishmaniasis (CL) owing to dominancy of Phlebotomus tobbi, which is a probable vector of Leishmania infantum. About 11.26% of CL cases reported each year are from Imamoglu, Adana, and between 2008 and 2015, 223 cases of CL were reported. Leishmania infantum, which may be transmitted by P. tobbi, Phlebotomus neglectus/syriacus, and Phlebotomus perfiliewi, is referred as leishmaniasis factor in Adana. Thus, the aim of this study was to map the risk areas for each sand fly species using remote sensing images based on environmental factors and geographical characteristics. Two field works in two consecutive years (2013 and 2014) were conducted and six sand fly species were caught, four of which were identified as probable vector species. Field work results were compared with environmental data obtained from satellite images by univariate and binary logistic regression in PASW. ARCMAP 10.2 software was used for geographical adjustments, creating a database and estimating a risk model by using previous risk value formulas. The results showed that the distribution of three probable leishmaniasis vectors (P. tobbi, P. neglectus/syriacus, and P. perfiliewi) was associated with normalized difference vegetation index (NDVI), digital elevation model (DEM), night-time land surface temperature (LSTNIGHT), and emissivity (EMIS31) values, which were related to the local authorities, who take these findings into account when deciding on high risk areas for CL.