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54 result(s) for "Dvorak, Vit"
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A novel MALDI-TOF MS-based method for blood meal identification in insect vectors: A proof of concept study on phlebotomine sand flies
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. 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. 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.
Species identification of phlebotomine sandflies using deep learning and wing interferential pattern (WIP)
Sandflies (Diptera; Psychodidae) are medical and veterinary vectors that transmit diverse parasitic, viral, and bacterial pathogens. Their identification has always been challenging, particularly at the specific and sub-specific levels, because it relies on examining minute and mostly internal structures. Here, to circumvent such limitations, we have evaluated the accuracy and reliability of Wing Interferential Patterns (WIPs) generated on the surface of sandfly wings in conjunction with deep learning (DL) procedures to assign specimens at various taxonomic levels. Our dataset proves that the method can accurately identify sandflies over other dipteran insects at the family, genus, subgenus, and species level with an accuracy higher than 77.0%, regardless of the taxonomic level challenged. This approach does not require inspection of internal organs to address identification, does not rely on identification keys, and can be implemented under field or near-field conditions, showing promise for sandfly pro-active and passive entomological surveys in an era of scarcity in medical entomologists.
Identification of phlebotomine sand flies (Diptera: Psychodidae) by matrix-assisted laser desorption/ionization time of flight mass spectrometry
BACKGROUND: Phlebotomine sand flies are incriminated in the transmission of several human and veterinary pathogens. To elucidate their role as vectors, proper species identification is crucial. Since traditional morphological determination is based on minute and often dubious characteristics on their head and genitalia, which require certain expertise and may be damaged in the field-collected material, there is a demand for rapid, simple and cost-effective molecular approaches. METHODS: Six laboratory-reared colonies of phlebotomine sand flies belonging to five species and four subgenera (Phlebotomus, Paraphlebotomus, Larroussius, Adlerius) were used to evaluate the discriminatory power of matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS). Various storage conditions and treatments, including the homogenization in either distilled water or given concentrations of formic acid, were tested on samples of both sexes. RESULTS: Specimens of all five analysed sand fly species produced informative, reproducible and species-specific protein spectra that enabled their conclusive species identification. The method also distinguished between two P. sergenti colonies originating from different geographical localities. Protein profiles within a species were similar for specimens of both sexes. Tested conditions of specimen storage and sample preparation give ground to a standard protocol that is generally applicable on analyzed sand fly specimens. CONCLUSIONS: Species identification of sand flies by MALDI-TOF MS is feasible and represents a novel promising tool to improve biological and epidemiological studies on these medically important insects.
Phlebotomine Sand Flies in Southern Thailand: Entomological Survey, Identification of Blood Meals and Molecular Detection of Trypanosoma spp
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.
Recent advances in Phlebotomine sand fly research: a review based on studies presented at ISOPS XI
The 11th International Symposium on Phlebotomine Sand flies (ISOPS XI) took place in Portorož, Slovenia, in September 2024 and brought together experts from around the world to discuss recent advances in the biology, ecology and control of phlebotomine sand flies and the pathogens they transmit. This report summarises the key findings of the symposium and is organised thematically by session. Key topics included the development of refined experimental models of Leishmania transmission, new insights into the interactions between vector, parasite and microbiota, and the detection of Leishmania donovani in new geographic regions. Advances in molecular diagnostics and surveillance technologies were emphasised, as were emerging concerns about insecticide resistance. The potential of paratransgenesis and symbiont-based vector control approaches was also emphasised. In a separate session, the CLIMOS project was presented, which integrates climate monitoring, ecological modelling and public health tools to develop an early warning system (EWS) for sand fly-borne diseases. Overall, the contributions to the symposium reflect the dynamic development of sand fly research in response to global environmental change and emphasise the importance of international collaboration in combating emerging vector-borne diseases. Le 11e Symposium international sur les phlébotomes (ISOPS XI) s’est tenu à Portorož, en Slovénie, en septembre 2024. Il a réuni des experts du monde entier pour discuter des avancées récentes en biologie, en écologie et en lutte contre les phlébotomes et les agents pathogènes qu’ils transmettent. Cette revue résume les principaux résultats présentés lors du symposium, organisés par session thématique. Les principaux sujets abordés comprenaient le développement de modèles expérimentaux affinés de transmission de Leishmania , de nouvelles connaissances sur les interactions vecteur-parasite-microbiote et la détection de Leishmania donovani dans de nouvelles régions géographiques. Les avancées en matière de diagnostic moléculaire et de technologies de surveillance ont été mises en avant, ainsi que les préoccupations émergentes concernant la résistance aux insecticides. Le potentiel de la paratransgénèse et des approches de lutte antivectorielle basées sur les symbiotes a également été souligné. Une session dédiée a présenté le projet CLIMOS, qui intègre la surveillance du climat, la modélisation écologique et des outils de santé publique pour développer un système d’alerte précoce (SAP) pour les maladies transmises par les phlébotomes. Collectivement, les contributions du symposium reflètent l’évolution dynamique de la recherche sur les phlébotomes face aux changements environnementaux mondiaux et soulignent l’importance de la collaboration internationale pour faire face aux menaces émergentes de maladies vectorielles.
Phlebotomine sand fly survey in the Republic of Moldova: species composition, distribution and host preferences
Background Phlebotomine sand flies (Diptera: Psychodiae) in the Republic of Moldova have been understudied for decades. Our study provides a first update on their occurrence, species composition and bloodmeal sources after 50 years. Methods During 5 seasons (2013–2017), 58 localities from 20 regions were surveyed for presence of sand flies using CDC light traps and manual aspirators. Species identification was done by a combination of morphological and molecular approaches (DNA barcoding, MALDI-TOF MS protein profiling). In engorged females, host blood was identified by three molecular techniques (RFLP, cytb sequencing and MALDI-TOF peptide mass mapping). Population structure of most abundant species was studied by cox 1 haplotyping; phylogenetic analyses of ITS2 and cox 1 genetic markers were used to resolve relationships of other detected species. Results In total, 793 sand flies were collected at 30 (51.7%) localities from 12 regions of Moldova. Three species were identified by an integrative morphological and molecular approach: Phlebotomus papatasi , P. perfiliewi and Phlebotomus sp. ( Adlerius ), the first being the most abundant and widespread, markedly anthropophilic based on bloodmeal analyses, occurring also indoors and showing low population structure with only five haplotypes of cox 1 detected. Distinct morphological and molecular characters of Phlebotomus sp. ( Adlerius ) specimens suggest the presence of a yet undescribed species. Conclusions Our study revealed the presence of stable sand fly populations of three species in Moldova that represent a biting nuisance as well as a potential threat of pathogen transmission and shall be further studied. Graphical abstract
Sand flies (Diptera: Psychodidae) in eight Balkan countries: historical review and region-wide entomological survey
Background Sand flies (Diptera: Psychodidae) are medically important vectors of human and veterinary disease-causing agents. Among these, the genus Leishmania (Kinetoplastida: Trypanosomatidae), and phleboviruses are of utmost importance. Despite such significance, updated information about sand fly fauna is missing for Balkan countries where both sand flies and autochtonous leishmaniases are historically present and recently re-emerging. Therefore, a review of historical data on sand fly species composition and distribution in the region was followed by a large-scale entomological survey in eight Balkan countries to provide a recent update on local sand fly fauna. Methods The literature search involved the period 1910–2019. The entomological survey was conducted at 1189 sampling stations in eight countries (Bulgaria, Bosnia and Herzegovina, Croatia, Kosovo, Montenegro, North Macedonia, Serbia and Slovenia), covering 49 settlements and 358 sampling sites between June and October in the years 2014 and 2016, accumulating 130 sampling days. We performed a total of 1189 trapping nights at these stations using two types of traps (light and CO 2 attraction traps) in each location. Sampling was performed with a minimal duration of 6 (Montenegro) and a maximal of 47 days (Serbia) between 0–1000 m.a.s.l. Collected sand flies were morphologically identified. Results In total, 8490 sand fly specimens were collected. Morphological identification showed presence of 14 species belonging to genera Phlebotomus and Sergentomyia. Historical data were critically reviewed and updated with our recent findings. Six species were identified in Bosnia and Herzegovina (2 new records), 5 in Montenegro (2 new records), 5 in Croatia (2 new records), 9 in Bulgaria (5 new records), 11 in North Macedonia (1 new record), 10 in Serbia (no new records), 9 in Kosovo (3 new records) and 4 in Slovenia (no new records). Conclusions This study presents results of the first integrated sand fly fauna survey of such scale for the Balkan region, providing first data on sand fly populations for four countries in the study area and presenting new species records for six countries and updated species lists for all surveyed countries. Our findings demonstrate presence of proven and suspected vectors of several Leishmania species. Graphical Abstract
First record of Phlebotomus (Transphlebotomus) mascittii in Slovakia
A large-scale entomological survey was carried out in summer 2016 in the Czech Republic and Slovakia. It revealed, for the first time, the presence of the phlebotomine sand fly Phlebotomus (Transphlebotomus) mascittii Grassi, 1908 (Diptera: Phlebotominae) in south-western Slovakia. Species identification of a captured female was confirmed by both morphological and sequencing (COI) analyses. Une enquête entomologique à grande échelle a été réalisée durant l'été 2016 en République Tchèque et en Slovaquie. Elle a révélé, pour la première fois, la présence de Phlebotomus (Transphlebotomus) mascittii Grassi, 1908 (Diptera : Phlebotominae) dans le sud-ouest de la Slovaquie. Une femelle a été capturée et son identification repose sur des caractères morphologiques et moléculaires (COI).
An integrative approach to identify sand fly vectors of leishmaniasis in Ethiopia by morphological and molecular techniques
Background Ethiopia is affected by human leishmaniasis caused by several Leishmania species and transmitted by a variety of sand fly vectors of the genus Phlebotomus . The sand fly fauna in Ethiopia is highly diverse and some species are closely related and similar in morphology, resulting in difficulties with species identification that requires deployment of molecular techniques. DNA barcoding entails high costs, requires time and lacks reference sequences for many Ethiopian species. Yet, proper species identification is pivotal for epidemiological surveillance as species differ in their actual involvement in transmission cycles. Recently, protein profiling using MALDI-TOF mass spectrometry has been introduced as a promising technique for sand fly identification. Methods In our study, we used an integrative taxonomic approach to identify most of the important sand fly vectors of leishmaniasis in Ethiopia, applying three complementary methods: morphological assessment, sequencing analysis of two genetic markers, and MALDI-TOF MS protein profiling. Results Although morphological assessment resulted in some inconclusive identifications, both DNA- and protein-based techniques performed well, providing a similar hierarchical clustering pattern for the analyzed species. Both methods generated species-specific sequences or protein patterns for all species except for Phlebotomus pedifer and P. longipes , the two presumed vectors of Leishmania aethiopica , suggesting that they may represent a single species, P. longipes Parrot & Martin. All three approaches also revealed that the collected specimens of Adlerius sp. differ from P. ( Adlerius ) arabicus , the only species of Adlerius currently reported in Ethiopia, and molecular comparisons indicate that it may represent a yet undescribed new species. Conclusions Our study uses three complementary taxonomical methods for species identification of taxonomically challenging and yet medically import Ethiopian sand flies. The generated MALDI-TOF MS protein profiles resulted in unambiguous identifications, hence showing suitability of this technique for sand fly species identification. Furthermore, our results contribute to the still inadequate knowledge of the sand fly fauna of Ethiopia, a country severely burdened with human leishmaniasis. Graphical Abstract
Human immune response against salivary antigens of Simulium damnosum s.l.: A new epidemiological marker for exposure to blackfly bites in onchocerciasis endemic areas
Background Simulium damnosum sensu lato (s.l.) blackflies transmit Onchocerca volvulus, a filarial nematode that causes human onchocerciasis. Human landing catches (HLCs) is currently the sole method used to estimate blackfly biting rates but is labour-intensive and questionable on ethical grounds. A potential alternative is to measure host antibodies to vector saliva deposited during bloodfeeding. In this study, immunoassays to quantify human antibody responses to S. damnosum s.l. saliva were developed, and the salivary proteome of S. damnosum s.l. was investigated. Methodology/Principal findings Blood samples from people living in onchocerciasis-endemic areas in Ghana were collected during the wet season; samples from people living in Accra, a blackfly-free area, were considered negative controls and compared to samples from blackfly-free locations in Sudan. Blackflies were collected by HLCs and dissected to extract their salivary glands. An ELISA measuring anti-S. damnosum s.l. salivary IgG and IgM was optimized and used to quantify the humoral immune response of 958 individuals. Both immunoassays differentiated negative controls from endemic participants. Salivary proteins were separated by gel-electrophoresis, and antigenic proteins visualized by immunoblot. Liquid chromatography mass spectrometry (LC-MS/MS) was performed to characterize the proteome of S. damnosum s.l. salivary glands. Several antigenic proteins were recognized, with the major ones located around 15 and 40 kDa. LC-MS/MS identified the presence of antigen 5-related protein, apyrase/nucleotidase, and hyaluronidase. Conclusions/Significance This study validated for the first time human immunoassays that quantify humoral immune responses as potential markers of exposure to blackfly bites. These assays have the potential to facilitate understanding patterns of exposure as well as evaluating the impact of vector control on biting rates. Future studies need to investigate seasonal fluctuations of these antibody responses, potential cross-reactions with other bloodsucking arthropods, and thoroughly identify the most immunogenic proteins.