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1.
Rev Soc Bras Med Trop ; 53: e20190503, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32267457

RESUMO

INTRODUCTION: The genus Rhodnius in the subfamily Triatominae comprises 20 species, which can transmit Trypanosoma cruzi and Trypanosoma rangeli. Due to the development of molecular techniques, Triatominae species can now be characterized by mitochondrial and nuclear markers, making it possible to verify and/or correct the existing data on these species. The results achieved in this study provide a more detailed and accurate differentiation of the Rhodnius species, helping the establishment of a more appropriate classification. METHODS: Data collection was performed by DNA analysis, morphological and morphometric studies to distinguish four populations of R. neglectus and four of R. prolixus. Phylogenetic data were compared to morphological and morphometric data. RESULTS: The analysis of Cytb fragments suggests that the four colonies designated to Rhodnius neglectus as well as those of R. prolixus were correctly identified. CONCLUSIONS: The morphological characters observed in the specimens of the colonies originally identified as R. prolixus and R. neglectus, such as the presence or absence of collar in the eggs, the patterns of the median process of the pygophore, and anterolateral angle, are consistent with the species. Geometric morphometrics also show an intraspecific variability in R. prolixus.


Assuntos
Insetos Vetores/anatomia & histologia , Rhodnius/classificação , Animais , Doença de Chagas/transmissão , Insetos Vetores/classificação , Insetos Vetores/genética , Masculino , Filogenia , Rhodnius/anatomia & histologia , Rhodnius/genética , Análise de Sequência de DNA , Especificidade da Espécie
2.
Infect Dis Poverty ; 9(1): 30, 2020 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-32183909

RESUMO

BACKGROUND: As of 2015 thousands of refugees are being hosted in temporary refugee camps in Greece. Displaced populations, travelling and living under poor conditions with limited access to healthcare are at a high risk of exposure to vector borne disease (VBD). This study sought to evaluate the risk for VBD transmission within refugee camps in Greece by analyzing the mosquito and sand fly populations present, in light of designing effective and efficient context specific vector and disease control programs. METHODS: A vector/pathogen surveillance network targeting mosquitoes and sand flies was deployed in four temporary refugee camps in Greece. Sample collections were conducted bi-weekly during June-September 2017 with the use of Centers for Disease Control (CDC) light traps and oviposition traps. Using conventional and molecular diagnostic tools we investigated the mosquito/sand fly species composition, population dynamics, pathogen infection rates, and insecticide resistance status in the major vector species. RESULTS: Important disease vectors including Anopheles sacharovi, Culex pipiens, Aedes albopictus and the Leishmania vectors Phlebotomus neglectus, P. perfiliewi and P. tobbi were recorded in the study refugee camps. No mosquito pathogens (Plasmodium parasites, flaviviruses) were detected in the analysed samples yet high sand fly Leishmania infection rates are reported. Culex pipiens mosquitoes displayed relatively high knock down resistance (kdr) mutation allelic frequencies (ranging from 41.0 to 63.3%) while kdr mutations were also detected in Ae. albopictus populations, but not in Anopheles and sand fly specimens. No diflubenzuron (DFB) mutations were detected in any of the mosquito species analysed. CONCLUSIONS: Important disease vectors and pathogens in vectors (Leishmania spp.) were recorded in the refugee camps indicating a situational risk factor for disease transmission. The Cx. pipiens and Ae. albopictus kdr mutation frequencies recorded pose a potential threat against the effectiveness of pyrethroid insecticides in these settings. In contrast, pyrethroids appear suitable for the control of Anopheles mosquitoes and sand flies and DFB for Cx. pipiens and Ae. albopictus larvicide applications. Targeted actions ensuring adequate living conditions and the establishment of integrated vector-borne disease surveillance programs in refugee settlements are essential for protecting refugee populations against VBDs.


Assuntos
Insetos Vetores/efeitos dos fármacos , Insetos Vetores/genética , Resistência a Inseticidas/genética , Leishmania , Controle de Mosquitos , Mosquitos Vetores/efeitos dos fármacos , Mosquitos Vetores/genética , Dinâmica Populacional , Campos de Refugiados , Aedes/efeitos dos fármacos , Aedes/genética , Animais , Anopheles/efeitos dos fármacos , Anopheles/genética , Culex/efeitos dos fármacos , Culex/genética , Feminino , Grécia , Leishmania/genética , Leishmania/patogenicidade , Leishmaniose/epidemiologia , Phlebotomus/efeitos dos fármacos , Phlebotomus/genética , Psychodidae
3.
PLoS Negl Trop Dis ; 14(2): e0007855, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-32092056

RESUMO

Glossina pallidipes is the main vector of animal African trypanosomiasis and a potential vector of human African trypanosomiasis in eastern Africa where it poses a large economic burden and public health threat. Vector control efforts have succeeded in reducing infection rates, but recent resurgence in tsetse fly population density raises concerns that vector control programs require improved strategic planning over larger geographic and temporal scales. Detailed knowledge of population structure and dispersal patterns can provide the required information to improve planning. To this end, we investigated the phylogeography and population structure of G. pallidipes over a large spatial scale in Kenya and northern Tanzania using 11 microsatellite loci genotyped in 600 individuals. Our results indicate distinct genetic clusters east and west of the Great Rift Valley, and less distinct clustering of the northwest separate from the southwest (Serengeti ecosystem). Estimates of genetic differentiation and first-generation migration indicated high genetic connectivity within genetic clusters even across large geographic distances of more than 300 km in the east, but only occasional migration among clusters. Patterns of connectivity suggest isolation by distance across genetic breaks but not within genetic clusters, and imply a major role for river basins in facilitating gene flow in G. pallidipes. Effective population size (Ne) estimates and results from Approximate Bayesian Computation further support that there has been recent G. pallidipes population size fluctuations in the Serengeti ecosystem and the northwest during the last century, but also suggest that the full extent of differences in genetic diversity and population dynamics between the east and the west was established over evolutionary time periods (tentatively on the order of millions of years). Findings provide further support that the Serengeti ecosystem and northwestern Kenya represent independent tsetse populations. Additionally, we present evidence that three previously recognized populations (the Mbeere-Meru, Central Kenya and Coastal "fly belts") act as a single population and should be considered as a single unit in vector control.


Assuntos
Insetos Vetores/genética , Moscas Tsé-Tsé/genética , Animais , Ecossistema , Fluxo Gênico , Variação Genética , Genótipo , Insetos Vetores/classificação , Insetos Vetores/fisiologia , Quênia , Repetições de Microssatélites , Filogeografia , Densidade Demográfica , Dinâmica Populacional , Tanzânia , Moscas Tsé-Tsé/classificação , Moscas Tsé-Tsé/fisiologia
4.
Parasit Vectors ; 13(1): 18, 2020 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-31931885

RESUMO

BACKGROUND: The recent reference genome assembly and annotation of the Asian malaria vector Anopheles stephensi detected only one gene encoding the leucine-rich repeat immune factor APL1, while in the Anopheles gambiae and sibling Anopheles coluzzii, APL1 factors are encoded by a family of three paralogs. The phylogeny and biological function of the unique APL1 gene in An. stephensi have not yet been specifically examined. METHODS: The APL1 locus was manually annotated to confirm the computationally predicted single APL1 gene in An. stephensi. APL1 evolution within Anopheles was explored by phylogenomic analysis. The single or paralogous APL1 genes were silenced in An. stephensi and An. coluzzii, respectively, followed by mosquito survival analysis, experimental infection with Plasmodium and expression analysis. RESULTS: APL1 is present as a single ancestral gene in most Anopheles including An. stephensi but has expanded to three paralogs in an African lineage that includes only the Anopheles gambiae species complex and Anopheles christyi. Silencing of the unique APL1 copy in An. stephensi results in significant mosquito mortality. Elevated mortality of APL1-depleted An. stephensi is rescued by antibiotic treatment, suggesting that pathology due to bacteria is the cause of mortality, and indicating that the unique APL1 gene is essential for host survival. Successful Plasmodium development in An. stephensi depends upon APL1 activity for protection from high host mortality due to bacteria. In contrast, silencing of all three APL1 paralogs in An. coluzzii does not result in elevated mortality, either with or without Plasmodium infection. Expression of the single An. stephensi APL1 gene is regulated by both the Imd and Toll immune pathways, while the two signaling pathways regulate different APL1 paralogs in the expanded APL1 locus. CONCLUSIONS: APL1 underwent loss and gain of functions concomitant with expansion from a single ancestral gene to three paralogs in one lineage of African Anopheles. We infer that activity of the unique APL1 gene promotes longevity in An. stephensi by conferring protection from or tolerance to an effect of bacterial pathology. The evolution of an expanded APL1 gene family could be a factor contributing to the exceptional levels of malaria transmission mediated by human-feeding members of the An. gambiae species complex in Africa.


Assuntos
Anopheles/genética , Chaperonina 60/genética , Fatores Imunológicos/genética , Fragmentos de Peptídeos/genética , Animais , Anopheles/imunologia , Evolução Molecular , Dosagem de Genes , Proteínas de Insetos/genética , Insetos Vetores/genética , Longevidade/genética , Malária/imunologia , Malária/transmissão , Filogenia
5.
Acta Trop ; 201: 105225, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31654646

RESUMO

The Triatoma genus is paraphyletic, and its species are grouped into complexes and subcomplexes. Given the fact that species that make up a given subcomplex generally share chromosomal traits, we analyzed the distribution of AT- and CG-rich DNA of the T. brasiliensis species subcomplex, in order to establish affinities among members of the T. brasiliensis subcomplex based on chromatin and chromosome traits and develop an identification key for the four monophyletic Triatoma subcomplexes from South America. All species exhibited a CG-rich X sex chromosome and autosomes, as well as an AT-rich Y sex chromosome. This feature can be used as a diagnostic characteristic to determine whether a given species is a member of the T. brasiliensis subcomplex, because it enables the differentiation of these species from all Triatoma of South America. Thus, we confirmed the chromosomal relationship of the T. brasiliensis species subcomplex and developed a dichotomous key based on the chromocenter to differentiate the species from this subcomplex from the other monophyletic Triatoma subcomplexes from South America.


Assuntos
Classificação , Insetos Vetores/classificação , Insetos Vetores/genética , Triatoma/classificação , Triatoma/genética , Animais , Variação Genética , Masculino , América do Sul
6.
Parasit Vectors ; 12(1): 585, 2019 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-31842951

RESUMO

BACKGROUND: Triatoma rubrofasciata is the only kissing bug species distributed globally. In the Americas, this species transmits the parasite Trypanosoma cruzi, responsible for Chagas disease. The presence of T. rubrofasciata in several Asian countries has greatly increased recently. In Vietnam, it is found in large numbers, closely associated with human environments. Although T. rubrofasciata from Asia is not infected with Tryp. cruzi, it carries other parasites such as Trypanosoma lewisi and Trypanosoma conorhini. Reports of bites by T. rubrofasciata have increased significantly in several places of Vietnam, becoming a public health problem as it produces severe anaphylactic reactions. METHODS: Specimens of T. rubrofasciata were collected from seven provinces in central Vietnam. We analyzed different biological attributes (life-cycle, starvation resistance, feeding and reproductive capacities) and genetic characteristics (chromosomes and DNA sequences) of T. rubrofasciata from Vietnam and compared them with Brazilian specimens. Natural infection with Tryp. conorhini and Tryp. lewisi were analyzed in a sample of 100 collected insects. RESULTS: Species identification of T. rubrofasciata from central Vietnam was corroborated by genetic markers. Cytogenetic analyses showed that T. rubrofasciata from central Vietnam share the same chromosomal characteristics with individuals from Brazil and Hanoi. DNA sequence analyses of a mitochondrial cytochrome b gene fragment showed little variation between Old and New World specimens. Our study sample, compared with Brazilian individuals, showed a higher survival capacity revealed by a higher hatching rate (98% compared with 80.5%), a larger amount of blood taken in single meal and long-term starvation resistance. Furthermore, this species had a high natural rate of infection with Tryp. conorhini (46%) and Tryp. lewisi (27%). CONCLUSIONS: For T. rubrofasciata of Vietnam, a high rate of fecundity throughout the year, a high capacity for starvation, and its occurrence in synanthropic environments of urban areas with a high availability of food sources are risk factors to be taken into account by vector control campaigns. The several allergic reactions caused by their bites and their high infection with Tryp. lewisi highlight the need to implement specific control programmes for T. rubrofasciata in Vietnam.


Assuntos
Comportamento Alimentar , Insetos Vetores/fisiologia , Estágios do Ciclo de Vida , Reprodução , Triatoma/fisiologia , Animais , Brasil , Citocromos b/genética , Citogenética , Variação Genética , Genótipo , Insetos Vetores/classificação , Insetos Vetores/genética , Insetos Vetores/parasitologia , Cariótipo , Análise de Sequência de DNA , Triatoma/classificação , Triatoma/genética , Triatoma/parasitologia , Trypanosoma/isolamento & purificação , Vietnã
7.
PLoS Genet ; 15(11): e1008452, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31710597

RESUMO

Trypanosomatid parasites are causative agents of important human and animal diseases such as sleeping sickness and leishmaniasis. Most trypanosomatids are transmitted to their mammalian hosts by insects, often belonging to Diptera (or true flies). These are called dixenous trypanosomatids since they infect two different hosts, in contrast to those that infect just insects (monoxenous). However, it is still unclear whether dixenous and monoxenous trypanosomatids interact similarly with their insect host, as fly-monoxenous trypanosomatid interaction systems are rarely reported and under-studied-despite being common in nature. Here we present the genome of monoxenous trypanosomatid Herpetomonas muscarum and discuss its transcriptome during in vitro culture and during infection of its natural insect host Drosophila melanogaster. The H. muscarum genome is broadly syntenic with that of human parasite Leishmania major. We also found strong similarities between the H. muscarum transcriptome during fruit fly infection, and those of Leishmania during sand fly infections. Overall this suggests Drosophila-Herpetomonas is a suitable model for less accessible insect-trypanosomatid host-parasite systems such as sand fly-Leishmania.


Assuntos
Interações Hospedeiro-Parasita/genética , Leishmania/genética , Psychodidae/parasitologia , Trypanosomatina/genética , Animais , Drosophila melanogaster/genética , Drosophila melanogaster/parasitologia , Infecções por Euglenozoa/genética , Infecções por Euglenozoa/parasitologia , Infecções por Euglenozoa/transmissão , Humanos , Insetos Vetores/genética , Leishmania/patogenicidade , Leishmaniose/genética , Leishmaniose/parasitologia , Leishmaniose/transmissão , Psychodidae/genética , Trypanosomatina/patogenicidade
8.
Int J Mol Sci ; 20(20)2019 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-31600869

RESUMO

Tomato chlorosis virus (ToCV) is widespread, seriously impacting tomato production throughout the world. ToCV is semi-persistently transmitted by Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae). Currently, insect olfaction is being studied to develop novel pest control technologies to effectively control B. tabaci and whitefly-borne virus diseases. Despite current research efforts, no report has been published on the role of odorant-binding proteins (OBPs) in insect preference under the influence of plant virus. Our previous research showed that viruliferous B. tabaci preferred healthy plants at 48 h after virus acquisition. In this study, we determined the effect of OBPs on the host preference interactions of ToCV and whiteflies. Our results show that with the increase in acquisition time, the OBP gene expressions changed differently, and the OBP3 gene expression showed a trend of first rising and then falling, and reached the maximum at 48 h. These results indicate that OBP3 may participate in the host preference of viruliferous whiteflies to healthy plants. When the expression of the OBP3 gene was knocked down by an RNA interference (RNAi) technique, viruliferous Mediterranean (MED) showed no preference and the ToCV transmission rate was reduced by 83.3%. We conclude that OBP3 is involved in the detection of plant volatiles by viruliferous MED. Our results provide a theoretical basis and technical support for clarifying the transmission mechanism of ToCV by B. tabaci and could provide new avenues for controlling this plant virus and its vectors.


Assuntos
Crinivirus/fisiologia , Inativação Gênica , Insetos Vetores/genética , Insetos Vetores/virologia , Interferência de RNA , Receptores Odorantes/genética , Animais , Transmissão de Doença Infecciosa , Genes Reporter , Hemípteros/virologia , Interações Hospedeiro-Patógeno/genética , Lycopersicon esculentum/virologia , Doenças das Plantas/virologia
9.
Mem Inst Oswaldo Cruz ; 114: e190184, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31576903

RESUMO

American visceral leishmaniasis (AVL) has two main scenarios of transmission as follows: scattered cases in rural areas and urban outbreaks. Urban AVL is in active dispersion from the northeastern border of Argentina-Paraguay-Brazil to the South. The presence of Lutzomyia longipalpis was initially reported in urban environments in the northwestern border of the country. The presence of Lu. longipalpis, environmental variables associated with its distribution, and its genetic diversity were assessed in Salvador Mazza, Argentina, on the border with Bolivia. The genetic analysis showed high haplotype diversity, low nucleotide diversity, and low nucleotide polymorphism index. We discuss the hypothesis of an expanding urban population with introgressive hybridisation of older haplogroups found in their path in natural forest or rural environments, acquiring a new adaptability to urban environments, and the possibility of changes in vector capacity.


Assuntos
Distribuição Animal , Variação Genética/genética , Insetos Vetores/genética , Psychodidae/genética , Animais , Argentina , Bolívia , Brasil , DNA Mitocondrial/genética , Genes de Insetos/genética , Haplótipos , Insetos Vetores/classificação , Leishmaniose Cutânea/transmissão , Masculino , Filogeografia , Psychodidae/classificação
10.
Genome Biol ; 20(1): 187, 2019 09 02.
Artigo em Inglês | MEDLINE | ID: mdl-31477173

RESUMO

BACKGROUND: Tsetse flies (Glossina sp.) are the vectors of human and animal trypanosomiasis throughout sub-Saharan Africa. Tsetse flies are distinguished from other Diptera by unique adaptations, including lactation and the birthing of live young (obligate viviparity), a vertebrate blood-specific diet by both sexes, and obligate bacterial symbiosis. This work describes the comparative analysis of six Glossina genomes representing three sub-genera: Morsitans (G. morsitans morsitans, G. pallidipes, G. austeni), Palpalis (G. palpalis, G. fuscipes), and Fusca (G. brevipalpis) which represent different habitats, host preferences, and vectorial capacity. RESULTS: Genomic analyses validate established evolutionary relationships and sub-genera. Syntenic analysis of Glossina relative to Drosophila melanogaster shows reduced structural conservation across the sex-linked X chromosome. Sex-linked scaffolds show increased rates of female-specific gene expression and lower evolutionary rates relative to autosome associated genes. Tsetse-specific genes are enriched in protease, odorant-binding, and helicase activities. Lactation-associated genes are conserved across all Glossina species while male seminal proteins are rapidly evolving. Olfactory and gustatory genes are reduced across the genus relative to other insects. Vision-associated Rhodopsin genes show conservation of motion detection/tracking functions and variance in the Rhodopsin detecting colors in the blue wavelength ranges. CONCLUSIONS: Expanded genomic discoveries reveal the genetics underlying Glossina biology and provide a rich body of knowledge for basic science and disease control. They also provide insight into the evolutionary biology underlying novel adaptations and are relevant to applied aspects of vector control such as trap design and discovery of novel pest and disease control strategies.


Assuntos
Genoma de Inseto , Genômica , Insetos Vetores/genética , Trypanosoma/parasitologia , Moscas Tsé-Tsé/genética , Animais , Elementos de DNA Transponíveis/genética , Drosophila melanogaster/genética , Feminino , Regulação da Expressão Gênica , Genes de Insetos , Genes Ligados ao Cromossomo X , Geografia , Proteínas de Insetos/genética , Masculino , Mutagênese Insercional/genética , Filogenia , Sequências Repetitivas de Ácido Nucleico/genética , Homologia de Sequência de Aminoácidos , Sintenia/genética , Wolbachia/genética
11.
Infect Dis Poverty ; 8(1): 70, 2019 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-31409377

RESUMO

BACKGROUND: Most species of Triatominae live exclusively in Latin America. However, one species, Triatoma rubrofasciata, has been recorded in the Americas as well as in various port areas in Africa and Asia. An increasing number of T. rubrofasciata have been reported in southern China in recent years. However, the origin of this invasive insect vector in China remains unknown, therefore, accurate identification and phylogenetic analysis of the bugs are urgently needed. METHODS: A total of seven triatomine insect specimens were found and collected from Maoming City, Guangdong Province, China (GDMM) and Zhangzhou City, Fujian Province, China (FJZZ), respectively. The obtained insect vector specimens were observed under a dissecting microscope for morphological classification and then the genomic DNA was extracted, and the 16S ribosomal RNA (rRNA), 28S rRNA as well as cytochrome oxidase subunit I (COI) genes of the species were amplified and sequenced. Subsequently, molecular phylogenetic analyses based on multiple alignments of the above genes were conducted in order to identify the species and determine the phylogenetic origin approximation accurately. RESULTS: The triatomine insects collected from GDMM and FJZZ were identified as Triatoma rubrofasciata using morphological and genetic analyses. All of the Chinese T. rubrofasciata captured in FJZZ, GDMM and other localities in southern China, together with a Vietnamese and Brazilian strain, formed a new, cohesive clade. T. rubrofasciata in GDMM and FJZZ are likely derived from strains found in Vietnam or Brazil. CONCLUSIONS: To the best of our knowledge, this is the first record of the invasive insect T. rubrofasciata, which is likely derived from strains native to Vietnam or Brazil, in both Maoming City, Guangdong Province and Zhangzhou City, Fujian Province of China. A comparison of the DNA sequences of the 16 s rRNA, 28 s rRNA and COI genes confirmed the specific identification of T. rubrofasciata, and its potential origin in China is based on the phylogenetic analyses undertaken in this study. More targeted interventions and improved entomological surveillance are urgently needed to control the spread of this haematophagous insect in China.


Assuntos
Distribuição Animal , Insetos Vetores/classificação , Triatoma/classificação , Animais , China , Complexo IV da Cadeia de Transporte de Elétrons/análise , Insetos Vetores/anatomia & histologia , Insetos Vetores/genética , Filogenia , RNA Ribossômico 16S/análise , RNA Ribossômico 28S/análise , Triatoma/anatomia & histologia , Triatoma/genética
12.
Gigascience ; 8(8)2019 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-31425588

RESUMO

BACKGROUND: Triatoma rubrofasciata is a widespread pathogen vector for Chagas disease, an illness that affects approximately 7 million people worldwide. Despite its importance to human health, its evolutionary origin has not been conclusively determined. A reference genome for T. rubrofasciata is not yet available. FINDING: We have sequenced the genome of a female individual with T. rubrofasciatausing a single molecular DNA sequencing technology (i.e., PacBio Sequel platform) and have successfully reconstructed a whole-genome (680-Mb) assembly that covers 90% of the nuclear genome (757 Mb). Through Hi-C analysis, we have reconstructed full-length chromosomes of this female individual that has 13 unique chromosomes (2n = 24 = 22 + X1 + X2) with a contig N50 of 2.72 Mb and a scaffold N50 of 50.7 Mb. This genome has achieved a high base-level accuracy of 99.99%. This platinum-grade genome assembly has 12,691 annotated protein-coding genes. More than 95.1% of BUSCO genes were single-copy completed, indicating a high level of completeness of the genome. CONCLUSION: The platinum-grade genome assembly and its annotation provide valuable information for future in-depth comparative genomics studies, including sexual determination analysis in T. rubrofasciata and the pathogenesis of Chagas disease.


Assuntos
Cromossomos de Insetos , Genoma , Genômica , Insetos Vetores/genética , Animais , Doença de Chagas/parasitologia , Doença de Chagas/transmissão , Biologia Computacional/métodos , Genômica/métodos , Insetos Vetores/classificação , Anotação de Sequência Molecular , Filogenia , Sequências Repetitivas de Ácido Nucleico , Triatoma/parasitologia
13.
PLoS Negl Trop Dis ; 13(8): e0007554, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31437154

RESUMO

BACKGROUND: In the last four decades, the Asian tiger mosquito, Aedes albopictus, vector of several human arboviruses, has spread from its native range in South-East Asia to all over the world, largely through the transportation of its eggs via the international trade in used tires. Albania was the first country invaded in Europe in 1979, followed by Italy in 1990 and other Mediterranean countries after 2000. METHODS/PRINCIPAL FINDINGS: We here inferred the invasion history and migration patterns of Ae. albopictus in Italy (today the most heavily-infested country in Europe), Greece and Albania, by analyzing a panel of >100,000 single nucleotide polymorphisms (SNPs) obtained by sequencing of double-digest Restriction site-Associated DNA (ddRADseq). The obtained dataset was combined with samples previously analyzed from both the native and invasive range worldwide to interpret the results using a broader spatial and historical context. The emerging evolutionary scenario complements the results of other studies in showing that the extraordinary worldwide expansion of Ae. albopictus has occurred thanks to multiple independent invasions by large numbers of colonists from multiple geographic locations in both native and previously invaded areas, consistently with the role of used tires shipments to move large numbers of eggs worldwide. By analyzing mosquitoes from nine sites across ~1,000-km transect in Italy, we were able to detect a complex interplay of drift, isolation by distance mediated divergence, and gene flow in shaping the species very recent invasion and range expansion, suggesting overall high connectivity, likely due to passive transportation of adults via ground transportation, as well as specific adaptations to local conditions. CONCLUSIONS/SIGNIFICANCE: Results contribute to characterize one of the most successful histories of animal invasion, and could be used as a baseline for future studies to track epidemiologically relevant characters (e.g. insecticide resistance).


Assuntos
Aedes/genética , Evolução Biológica , Insetos Vetores/genética , Metagenômica , Aedes/classificação , Albânia , Migração Animal , Animais , Europa (Continente) , Fluxo Gênico , Variação Genética , Grécia , Insetos Vetores/classificação , Espécies Introduzidas , Itália , Filogenia , Polimorfismo de Nucleotídeo Único
14.
Parasit Vectors ; 12(1): 410, 2019 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-31439012

RESUMO

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.


Assuntos
Código de Barras de DNA Taxonômico , Proteínas de Insetos/genética , Insetos Vetores/classificação , Phlebotomus/classificação , Animais , Ciclo-Oxigenase 1/genética , Complexo IV da Cadeia de Transporte de Elétrons/genética , Feminino , Geografia , Insetos Vetores/genética , Masculino , Phlebotomus/genética , Turquia
15.
Mem Inst Oswaldo Cruz ; 114: e190034, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31433005

RESUMO

Six Phlebotominae sand fly species are incriminated as biological vectors of human pathogens in Panama, but molecular corroboration is still needed. We aim at confirming the identity of Phlebotominae species documented as anthropophilic in Panama. Adult sandflies were collected from August 2010 to February 2012 in Central Panama using CDC light traps. Species confirmation was accomplished through molecular barcodes and allied sequences from GenBank. A total of 53,366 sand fly specimens representing 18 species were collected. Five species were validated molecularly as single phylogenetic clusters, but Psychodopygus thula depicted two genetically divergent lineages, which may be indicative of cryptic speciation.


Assuntos
Biodiversidade , Insetos Vetores/genética , Psychodidae/genética , Animais , Insetos Vetores/classificação , Leishmaniose Cutânea/transmissão , Panamá , Filogenia , Psychodidae/classificação
16.
PLoS Negl Trop Dis ; 13(7): e0007568, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31344039

RESUMO

The tsetse fly, Glossina morsitans morsitans, is a significant problem in Zambia and Malawi. It is the vector for the human infective parasite Trypanosoma brucei rhodesiense, which causes human African trypanosomiasis, and various Trypanosoma species, which cause African animal trypanosomiasis. Understanding the genetic diversity and population structure of G. m. morsitans is the basis of elucidating the connectivity of the tsetse fly populations, information that is essential in implementing successful tsetse fly control activities. This study conducted a population genetic study using partial mitochondrial cytochrome oxidase gene 1 (CO1) and 10 microsatellite loci to investigate the genetic diversity and population structure of G. m. morsitans captured in the major HAT foci in Zambia and Malawi. We have included 108 and 99 G. m. morsitans samples for CO1 and microsatellite analyses respectively. Our results suggest the presence of two different genetic clusters of G. m. morsitans, existing East and West of the escarpment of the Great Rift Valley. We have also revealed genetic similarity between the G. m. morsitans in Kasungu National Park and those in the Luangwa river basin in Zambia, indicating that this population should also be included in this historical tsetse belt. Although further investigation is necessary to illustrate the whole picture in East and Southern Africa, this study has extended our knowledge of the population structure of G. m. morsitans in Southern Africa.


Assuntos
Variação Genética , Tripanossomíase Africana/parasitologia , Moscas Tsé-Tsé/genética , Animais , Complexo IV da Cadeia de Transporte de Elétrons/genética , Feminino , Genética Populacional , Haplótipos , Humanos , Insetos Vetores/genética , Malaui , Masculino , Repetições de Microssatélites , Filogeografia , Moscas Tsé-Tsé/enzimologia , Zâmbia
17.
Med Vet Entomol ; 33(4): 521-529, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31155766

RESUMO

Several species of Leishmania are responsible for leishmaniases in Thailand, although little is known about their transmission. Sergentomyia gemmea has been suspected several times to transmit Leishmania martiniquensis. Some captures carried out in Thailand and Lao People's Democratic Republic have emphasized the scarcity of Se. gemmea, comprising only 1% of the collected females. The sequencing of cytochrome B mtDNA of our specimens showed that our specimens are not grouped with other Se. gemmea previously deposited in GenBank. The latter are grouped with some Se. khawi and Se. hivernus that we processed in the present study. We suspect misidentifications and propose focusing on the most useful characters for identification of Se. gemmea based on the examination of type-specimens. The examination of the ascoids exhibiting anterior spurs is the most important one. However, we also describe Se. raynali n. sp. exhibiting comparable spurs but differing from Se. gemmea by its original cibarium. Finally, the vectorial role of Se. gemmea appears very questionable in the absence of new evidence.


Assuntos
Insetos Vetores/classificação , Psychodidae/classificação , Animais , Citocromos b/análise , DNA Mitocondrial/análise , Feminino , Proteínas de Insetos/análise , Insetos Vetores/anatomia & histologia , Insetos Vetores/genética , Laos , Masculino , Psychodidae/anatomia & histologia , Psychodidae/genética , Análise de Sequência de DNA , Tailândia
18.
Parasit Vectors ; 12(1): 307, 2019 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-31215486

RESUMO

BACKGROUND: Haemosporidian parasites are transmitted by dipteran blood-sucking insects but certain vectors remain unidentified for the great majority of described species. Sensitive PCR-based methods are often used for the detection of haemosporidian infection in wild-caught insects. However, this approach alone cannot distinguish between different sporogonic stages and thus is insufficient to demonstrate that the parasites produce the infective stage (sporozoite), which is essential for transmission. To prove that PCR-positive insects could act as vectors, the record of sporozoites is needed. We developed a methodology for the determination of natural vectors of avian Haemoproteus species and other haemosporidians. The essence of this approach is to apply PCR-based and microscopic diagnostic tools in parallel for sporozoite detection in insects. METHODS: Culicoides biting midges transmit avian Haemoproteus parasites, but certain insect species, which are involved in transmission, remain insufficiently investigated. Biting midges were collected in the wild and identified; parous females were dissected and preparations of thorax content containing salivary glands were prepared. Remnants of the dissected midges were screened using PCR-based methods. Only thorax preparations of PCR-positive biting midges were examined microscopically. RESULTS: In total, 460 parous females belonging to 15 species were collected and dissected. DNA of haemosporidians was detected in 32 (7%) of dissected insects belonging to 7 species. Of the thorax samples PCR-positive for Haemoproteus parasites, two preparations were microscopically positive for sporozoites. Both biting midges were Culicoides kibunensis. Haemoproteus pallidus (hPFC1) was identified, indicating that transmission of this infection occurs at the study site. It was proved that seven species of biting midges take bird blood meals naturally in the wild. CONCLUSIONS: Culicoides kibunensis is a new vector species of avian haemoproteids and is a natural vector of H. pallidus. Numerous studies have identified vectors of Haemoproteus parasites experimentally; however, this is the first direct identification of a natural vector of Haemoproteus infection in the Old World. We suggest using the described methodology for vector research of Haemoproteus and other haemosporidians in the wild.


Assuntos
Aves/parasitologia , Ceratopogonidae/parasitologia , Haemosporida/isolamento & purificação , Insetos Vetores/parasitologia , Animais , Doenças das Aves/parasitologia , Doenças das Aves/transmissão , Feminino , Haemosporida/genética , Insetos Vetores/genética , Filogenia , Reação em Cadeia da Polimerase , Glândulas Salivares/parasitologia , Análise de Sequência de DNA , Esporozoítos/genética , Esporozoítos/isolamento & purificação , Tórax/parasitologia
19.
Virology ; 533: 137-144, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31247402

RESUMO

Angiotensin-converting enzyme (ACE) plays diverse roles in the animal kingdom. However, whether ACE plays an immune function against viral infection in vector insects is unclear. In this study, an ACE gene (LsACE) from the small brown planthopper was found to respond to Rice stripe virus (RSV) infection. The enzymatic activities of LsACE were characterized at different pH and temperature. Twenty planthopper proteins were found to interact with LsACE. RSV infection significantly upregulated LsACE expression in the testicle and fat body. When the expression of LsACE in viruliferous planthoppers was inhibited, the RNA level of the RSV SP gene was upregulated 2-fold in planthoppers, and all RSV genes showed higher RNA levels in the rice plants consumed by these planthoppers, leading to a higher viral infection rate and disease rating index. These results indicate that LsACE plays a role in the immune response against RSV transmission by planthoppers.


Assuntos
Hemípteros/imunologia , Hemípteros/virologia , Proteínas de Insetos/imunologia , Insetos Vetores/imunologia , Insetos Vetores/virologia , Peptidil Dipeptidase A/imunologia , Tenuivirus/fisiologia , Sequência de Aminoácidos , Animais , Hemípteros/genética , Hemípteros/fisiologia , Proteínas de Insetos/genética , Insetos Vetores/genética , Insetos Vetores/fisiologia , Oryza/virologia , Peptidil Dipeptidase A/genética , Filogenia , Doenças das Plantas/virologia , Tenuivirus/classificação , Tenuivirus/genética , Tenuivirus/isolamento & purificação
20.
J Insect Physiol ; 117: 103904, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31238055

RESUMO

Diaphorina citri Kuwayama, commonly known as Asian citrus psyllid (ACP), transmits the bacterium Candidatus Liberibacter asiaticus (CLas), one of the causative agents of Huanglongbing (HLB) to citrus trees. Within ACP populations, three adult abdominal color polymorphisms: gray/brown, blue/green, and orange/yellow have been described. Despite the economic importance of this insect, the molecular mechanisms governing reproduction and vitellogenesis are not well understood. The current results describe the expression patterns of VgA1-like and Kr-h1, ovary morphology, and oviposition behavior in two different ACP morphotypes. Our results showed that VgA1-like exhibited female sex-specific expression, was upregulated more in blue/green than gray/brown females, and increased in expression with age only in blue/green morphs. The transcription factor Kr-h1, associated with reproduction in some insect species, was expressed in both sexes, was upregulated in 1 and 7 days old blue/green compared to gray/brown females, and exhibited reduced expression by 14 days of age in both morphotypes. Our results demonstrated an association between VgA1-like expression, oocyte development, and the blue green abdominal color of D. citri, which were linked to higher reproductive output than observed in gray/brown females. Overall, this study described the importance of the genes VgA1-like and Kr-h1 in D. citri vitellogenesis, and explained the mechanisms underlying differential reproductive performance among D. citri abdominal color morphs.


Assuntos
Hemípteros/genética , Insetos Vetores/genética , Pigmentação , Vitelogênese , Animais , Feminino , Expressão Gênica , Genes de Insetos , Hemípteros/metabolismo , Insetos Vetores/metabolismo , Oócitos/crescimento & desenvolvimento , Oviposição
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