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1.
Acta Trop ; 219: 105913, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33831346

RESUMO

Biting midges in the genus Culicoides (Diptera; Ceratopogonidae) are vectors of pathogens that can cause diseases of major economic importance in humans and animals. Identifying host ranges of these biting midges might aid in understanding the complex epidemiology of such diseases, often involving reservoir hosts and multiple species. In this study, we aim to identify bloodmeal origin from engorged female Culicoides biting midges. All bloodfed females were opportunistically collected as part of an ongoing surveillance programme using Onderstepoort light traps in two provinces in South Africa. DNA of individuals was extracted and subjected to PCR targeting the cytochrome B (CytB) gene region of mammals and avians as well as cytochrome oxidase I (COI) for species identification. In total, 21 new reference barcodes were generated for C. bedfordi, C imicola, C. leucosticus, C. magnus, and C. pycnostictus. Seventy-four blood meals were identified, originating from 12 mammal and three avian species. COI sequence data performed well for species delimitation and 54 Culicoides specimens were identified with C. imicola the predominant species identified (41.8%). Generally, Culicoides species feed on a variety of hosts and host availability might be an important factor when selecting a host. Culicoides species thus appear to be opportunistic feeders rather than specialists. This implicates Culicoides as transfer vectors and demonstrates possible transmission routes of arboviruses and other pathogens from wildlife onwards to domestic animals and humans.


Assuntos
Sangue/parasitologia , Ceratopogonidae/classificação , Citocromos b/genética , Código de Barras de DNA Taxonômico , Complexo IV da Cadeia de Transporte de Elétrons/genética , Animais , Arbovírus/fisiologia , Ceratopogonidae/genética , Feminino , Especificidade de Hospedeiro , Humanos , Insetos Vetores/genética , África do Sul
2.
J Parasitol ; 107(2): 289-294, 2021 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-33844840

RESUMO

Members of the flea family Pulicidae have been the focus of many studies due to their significance as diseases vectors of medical and veterinary importance and their cosmopolitan distribution. They often exhibit variation in morphological features that can make correct species identification and management challenging. This may also apply to Xenopsylla brasiliensis (Baker, 1904), an important plague vector. In the current study, we aimed to provide genetic tools for reliable species identification using a DNA barcoding approach. A total of 73 flea specimens was collected from a native host (Namaqua rock mouse, Micaelamys namaquensis) in South Africa and identified morphologically. In addition, we took measurements of 7 morphological characteristics. Subsequently, we successfully generated barcodes of the mitochondrial cytochrome c oxidase subunit I (COI) gene for X. brasiliensis. We validated this approach by comparing our data to COI sequences from Rwandan X. brasiliensis. While sequences from both regions suggested a close relationship between the 2 X. brasiliensis populations, both haplotype and nucleotide diversity were substantially larger for the South African specimens. This may be attributed to human-assisted spread, differences in habitat, and/or host species sampled and merits further study in the future.


Assuntos
Insetos Vetores/anatomia & histologia , Insetos Vetores/genética , Peste/transmissão , Xenopsylla/anatomia & histologia , Xenopsylla/genética , Animais , Código de Barras de DNA Taxonômico , Complexo IV da Cadeia de Transporte de Elétrons/genética , Feminino , Infestações por Pulgas/parasitologia , Infestações por Pulgas/veterinária , Variação Genética , Haplótipos , Masculino , Mitocôndrias/enzimologia , Murinae/parasitologia , África do Sul
3.
Zootaxa ; 4963(3): zootaxa.4963.3.2, 2021 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-33903539

RESUMO

Haplaxius is a large genus of cixiid planthoppers that is widespread in the New World and economically important due to the role of H. crudus in transmitting palm lethal decline phytoplasmas. A new species of Haplaxius, here described as Haplaxius pocococo sp. n., was discovered during survey work on palms in north-central Costa Rica. Placement in Haplaxius is supported by sequence analysis of the COI and 18S genes relative to congeners and by morphological characters.


Assuntos
Cocos , Hemípteros , Insetos Vetores , Animais , Cocos/parasitologia , Costa Rica , Complexo IV da Cadeia de Transporte de Elétrons/genética , Hemípteros/anatomia & histologia , Hemípteros/classificação , Hemípteros/genética , Insetos Vetores/anatomia & histologia , Insetos Vetores/classificação , Insetos Vetores/genética , RNA Ribossômico 18S/genética , Especificidade da Espécie
4.
Mem Inst Oswaldo Cruz ; 116: e200528, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33656141

RESUMO

Panstrongylus geniculatus (Latreille, 1811) is the triatomine with the largest geographic distribution in Latin America. It has been reported in 18 countries from southern Mexico to northern Argentina, including the Caribbean islands. Although most reports indicate that P. geniculatus has wild habitats, this species has intrusive habits regarding human dwellings mainly located in intermediate deforested areas. It is attracted by artificial light from urban and rural buildings, raising the risk of transmission of Trypanosoma cruzi. Despite the wide body of published information on P. geniculatus, many knowledge gaps exist about its biology and epidemiological potential. For this reason, we analysed the literature for P. geniculatus in Scopus, PubMed, Scielo, Google Scholar and the BibTriv3.0 databases to update existing knowledge and provide better information on its geographic distribution, life cycle, genetic diversity, evidence of intrusion and domiciliation, vector-related circulating discrete taxonomic units, possible role in oral T. cruzi transmission, and the effect of climate change on its biology and epidemiology.


Assuntos
Doença de Chagas/transmissão , Insetos Vetores/parasitologia , Panstrongylus/genética , Panstrongylus/parasitologia , Triatoma/parasitologia , Trypanosoma cruzi , Animais , Biologia , Ecologia , Genes de Insetos , Variação Genética/genética , Genótipo , Geografia , Humanos , Insetos Vetores/genética , América Latina , Panstrongylus/fisiologia , Filogenia , Trypanosoma cruzi/isolamento & purificação
5.
Mem Inst Oswaldo Cruz ; 115: e200313, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33533870

RESUMO

BACKGROUND: Aedes aegypti is the sole vector of urban arboviruses in French Guiana. Overtime, the species has been responsible for the transmission of viruses during yellow fever, dengue, chikungunya and Zika outbreaks. Decades of vector control have produced resistant populations to deltamethrin, the sole molecule available to control adult mosquitoes in this French Territory. OBJECTIVES: Our surveillance aimed to provide public health authorities with data on insecticide resistance in Ae. aegypti populations and other species of interest in French Guiana. Monitoring resistance to the insecticide used for vector control and to other molecule is a key component to develop an insecticide resistance management plan. METHODS: In 2009, we started to monitor resistance phenotypes to deltamethrin and target-site mechanisms in Ae. aegypti populations across the territory using the WHO impregnated paper test and allelic discrimination assay. FINDINGS: Eight years surveillance revealed well-installed resistance and the dramatic increase of alleles on the sodium voltage-gated gene, known to confer resistance to pyrethroids (PY). In addition, we observed that populations were resistant to malathion (organophosphorous, OP) and alpha-cypermethrin (PY). Some resistance was also detected to molecules from the carbamate family. Finally, those populations somehow recovered susceptibility against fenitrothion (OP). In addition, other species distributed in urban areas revealed to be also resistant to pyrethroids. CONCLUSION: The resistance level can jeopardize the efficiency of chemical adult control in absence of other alternatives and conducts to strongly rely on larval control measures to reduce mosquito burden. Vector control strategies need to evolve to maintain or regain efficacy during epidemics.


Assuntos
Aedes/efeitos dos fármacos , Insetos Vetores/genética , Resistência a Inseticidas/genética , Inseticidas/farmacologia , Mosquitos Vetores/efeitos dos fármacos , Piretrinas/farmacologia , Aedes/genética , Aedes/virologia , Animais , Guiana Francesa , Insetos Vetores/efeitos dos fármacos , Controle de Mosquitos/métodos , Mosquitos Vetores/virologia , Análise Espaço-Temporal
6.
Acta Trop ; 217: 105866, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33607064

RESUMO

Biting midges of the genus Culicoides Latreille are blood sucking insects of medical and veterinary importance. Many species are vectors of disease agents transmitted to humans and other animals. Therefore, rapid and accurate species identification is essential for appreciation of all aspects of these insects. In this study, DNA barcode efficacy and molecular identification of host blood sources were examined in biting midges from Thailand. A total of 203 barcoding sequences were obtained from 16 Culicoides taxa. Intraspecific genetic divergence varied from 0.28% to 9.90% for specimens collected in Thailand. Despite this high level of genetic variation, DNA barcode identifications in the Barcoding of Life Data System had a considerable success rate (90%). Phylogenetic analyses and distance-based species delimitation methods indicated the possibility of cryptic species in four taxa, namely, Culicoides actoni Smit, C. arakawae Arakawa, C. huffi Causey and C. jacobsoni Macfie. Further investigations will be required to examine the species status of these lineages. Host blood meal identifications from 42 blood engorged females of 10 Culicoides taxa revealed three animal hosts: chicken, cattle and buffalo. Most of this information agrees with previous knowledge but this is the first report of C. actoni, C. fulvus and C. huffi feeding on chicken.


Assuntos
Ceratopogonidae/classificação , Ceratopogonidae/genética , Código de Barras de DNA Taxonômico , Variação Genética , Animais , Bovinos , Análise Mutacional de DNA , Feminino , Insetos Vetores/genética , Filogenia , Tailândia
7.
BMC Genomics ; 22(1): 71, 2021 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-33478394

RESUMO

BACKGROUND: In the light of dengue being the fastest growing transmissible disease, there is a dire need to identify the mechanisms regulating the behaviour of the main vector Aedes aegypti. Disease transmission requires the female mosquito to acquire the pathogen from a blood meal during one gonotrophic cycle, and to pass it on in the next, and the capacity of the vector to maintain the disease relies on a sustained mosquito population. RESULTS: Using a comprehensive transcriptomic approach, we provide insight into the regulation of the odour-mediated host- and oviposition-seeking behaviours throughout the first gonotrophic cycle. We provide clear evidence that the age and state of the female affects antennal transcription differentially. Notably, the temporal- and state-dependent patterns of differential transcript abundance of chemosensory and neuromodulatory genes extends across families, and appears to be linked to concerted differential modulation by subsets of transcription factors. CONCLUSIONS: By identifying these regulatory pathways, we provide a substrate for future studies targeting subsets of genes across disparate families involved in generating key vector behaviours, with the goal to develop novel vector control tools.


Assuntos
Aedes , Dengue , Aedes/genética , Animais , Dengue/genética , Feminino , Humanos , Insetos Vetores/genética , Mosquitos Vetores/genética , Transcriptoma
8.
Parasit Vectors ; 14(1): 20, 2021 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-33407822

RESUMO

BACKGROUND: Phlebotomine sand flies are the principal vectors of Leishmania spp. (Kinetoplastida: Trypanosomatidae). Information on sand flies in Central Europe is scarce and, to date, in Austria, only Phlebotomus mascittii has been recorded. In 2018 and 2019, entomological surveys were conducted in Austria with the aim to further clarify sand fly distribution and species composition. RESULTS: In 2019, a Ph. simici specimen was trapped in Austria for the first time. Analyses of two commonly used marker genes, cytochrome c oxidase I (coxI) and cytochrome b (cytb), revealed high sequence identity with Ph. simici specimens from North Macedonia and Greece. Phylogenetic analyses showed high intraspecific distances within Ph. simici, thereby dividing this species into three lineages: one each from Europe, Turkey and Israel. Low interspecific distances between Ph. simici, Ph. brevis and an as yet unidentified Adlerius sp. from Turkey and Armenia highlight how challenging molecular identification within the Adlerius complex can be, even when standard marker genes are applied. CONCLUSION: To our knowledge, this study reports the first finding of Ph. simici in Austria, representing the northernmost recording of this species to date. Moreover, it reveals valuable insights into the phylogenetic relationships among species within the subgenus Adlerius. Phlebotomus simici is a suspected vector of L. infantum and therefore of medical and veterinary importance. Potential sand fly expansion in Central Europe due to climatic change and the increasing import of Leishmania-infected dogs from endemic areas support the need for further studies on sand fly distribution in Austria and Central Europe in general.


Assuntos
Phlebotomus , Psychodidae , Animais , Austrália , Classificação , Citocromos b/genética , Vetores de Doenças , Complexo IV da Cadeia de Transporte de Elétrons/genética , Genes de Insetos , Insetos Vetores/classificação , Insetos Vetores/genética , Leishmaniose Visceral/transmissão , Phlebotomus/classificação , Phlebotomus/genética , Filogenia , Psychodidae/classificação , Psychodidae/genética
9.
Rev. Soc. Bras. Med. Trop ; 54: e00282020, 2021. tab, graf
Artigo em Inglês | LILACS, Coleciona SUS, Sec. Est. Saúde SP | ID: biblio-1143882

RESUMO

Abstract INTRODUCTION: We aimed to study intraspecific variation in Triatoma costalimai, a potential vector of Chagas disease present in Brazil and Bolivia. METHODS: We analyzed phenotypic (connexivum color patterns, wing morphometrics) and genetic variation (16S mtDNA) of three Brazilian T. costalimai populations. We compared 16S sequences with those of putative Bolivian T. costalimai and its sister species, T. jatai. RESULTS: Brazilian populations had different connexivum color patterns and forewing shapes. A 16S mtDNA haplotype network showed a clear separation of Brazilian T. costalimai from both T. jatai and Bolivian T. costalimai. CONCLUSIONS: We report considerable variability in T. costalimai populations.


Assuntos
Animais , Triatoma/genética , Doença de Chagas , Variação Genética/genética , Bolívia , Brasil , Insetos Vetores/genética
10.
Rev Soc Bras Med Trop ; 54: e00282020, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33338103

RESUMO

INTRODUCTION: We aimed to study intraspecific variation in Triatoma costalimai, a potential vector of Chagas disease present in Brazil and Bolivia. METHODS: We analyzed phenotypic (connexivum color patterns, wing morphometrics) and genetic variation (16S mtDNA) of three Brazilian T. costalimai populations. We compared 16S sequences with those of putative Bolivian T. costalimai and its sister species, T. jatai. RESULTS: Brazilian populations had different connexivum color patterns and forewing shapes. A 16S mtDNA haplotype network showed a clear separation of Brazilian T. costalimai from both T. jatai and Bolivian T. costalimai. CONCLUSIONS: We report considerable variability in T. costalimai populations.


Assuntos
Doença de Chagas , Triatoma , Animais , Bolívia , Brasil , Variação Genética/genética , Insetos Vetores/genética , Triatoma/genética
11.
Mem Inst Oswaldo Cruz ; 115: e200157, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33206821

RESUMO

BACKGROUND: In Acre state, Brazil, the dissemination of cutaneous leishmaniasis has increased in recent years, with limited knowledge of the potential Leishmania spp. vectors involved. OBJECTIVES: Here, data concerning the sandfly fauna of Brasiléia municipality, Leishmania DNA-detection rates and the identification of blood meal sources of insects captured in 2013-2015 are presented. METHODS: Parasite detection in female sandflies was performed individually by multiplex polymerase chain reaction (PCR) (Leishmania kDNA/sandfly cacophony-gene), with the identification of Leishmania spp. by hsp70-PCR and sequencing. The identification of blood gut-content from fed females was performed by cyt b-PCR and sequencing. FINDINGS: A total of 4,473 sandflies were captured. A subgroup of 864 non-blood-fed females evaluated for the presence of Leishmania DNA showed 2.9% positivity for Leishmania (Viannia) braziliensis and L. (V.) guyanensis. The identification of blood meal sources was performed in 96 blood-fed females, allowing the identification of 13 vertebrate species. In nine/96 fed females, DNA from L. (V.) shawi, L. (V.) guyanensis, L. (V.) braziliensis and Endotrypanum sp. was detected. MAIN CONCLUSIONS: In Brumptomyia sp. and Evandromyia termitophila, the first report of Leishmania DNA-detection is provided in Acre; Nyssomyia shawi is implicated as potential vector of L. (V.) braziliensis and L. (V.) guyanensis for the first time in Brazil.


Assuntos
DNA/análise , Insetos Vetores/genética , Leishmania/genética , Psychodidae/parasitologia , Animais , Brasil , DNA de Protozoário/análise , Feminino , Insetos Vetores/classificação , Insetos Vetores/parasitologia , Leishmania/isolamento & purificação , Leishmaniose Cutânea/transmissão , Reação em Cadeia da Polimerase , Psychodidae/classificação
12.
PLoS Pathog ; 16(8): e1008710, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32817722

RESUMO

Rice stripe virus (RSV, genus Tenuivirus, family Phenuiviridae) is the causal agent of rice stripe disease transmitted by the small brown planthopper (SBPH, Laodelphax striatellus) in a persistent propagative manner. The midgut and salivary glands of SBPH are the first and last barriers to the viral circulation and transmission processes, respectively; however, the precise mechanisms used by RSV to cross these organs and transmit to rice plants have not been fully elucidated. We obtained the full-length cDNA sequence of L. striatellus α-tubulin 2 (LsTUB) and found that RSV infection increased the level of LsTUB in vivo. Furthermore, LsTUB was shown to co-localize with RSV nonstructural protein 3 (NS3) in vivo and bound NS3 at positions 74-76 and 80-82 in vitro. Transient gene silencing of LsTUB expression caused a significant reduction in detectable RSV loads and viral NS3 expression levels, but had no effect on NS3 silencing suppressor activity and viral replication in insect cells. However, suppression of LsTUB attenuated viral spread in the bodies of SBPHs and decreased RSV transmission rates to rice plants. Electrical penetration graphs (EPG) showed that LsTUB knockdown by RNAi did not impact SBPH feeding; therefore, the reduction in RSV transmission rates was likely caused by a decrease in viral loads inside the planthopper. These findings suggest that LsTUB mediates the passage of RSV through midgut and salivary glands and leads to successful horizontal transmission.


Assuntos
Hemípteros/metabolismo , Proteínas de Insetos/metabolismo , Insetos Vetores/metabolismo , Oryza/virologia , Doenças das Plantas/virologia , Tenuivirus/fisiologia , Tubulina (Proteína)/metabolismo , Animais , Sistema Digestório/metabolismo , Sistema Digestório/virologia , Hemípteros/genética , Hemípteros/virologia , Proteínas de Insetos/genética , Insetos Vetores/genética , Insetos Vetores/virologia , Glândulas Salivares/metabolismo , Glândulas Salivares/virologia , Tubulina (Proteína)/genética
13.
PLoS Genet ; 16(8): e1008992, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32797092

RESUMO

Bacterial virulence factors facilitate host colonization and set the stage for the evolution of parasitic and mutualistic interactions. The Sodalis-allied clade of bacteria exhibit striking diversity in the range of both plant and animal feeding insects they inhabit, suggesting the appropriation of universal molecular mechanisms that facilitate establishment. Here, we report on the infection of the tsetse fly by free-living Sodalis praecaptivus, a close relative of many Sodalis-allied symbionts. Key genes involved in quorum sensing, including the homoserine lactone synthase (ypeI) and response regulators (yenR and ypeR) are integral for the benign colonization of S. praecaptivus. Mutants lacking ypeI, yenR and ypeR compromised tsetse survival as a consequence of their inability to repress virulence. Genes under quorum sensing, including homologs of the binary insecticidal toxin PirAB and a putative symbiosis-promoting factor CpmAJ, demonstrated negative and positive impacts, respectively, on tsetse survival. Taken together with results obtained from experiments involving weevils, this work shows that quorum sensing virulence suppression plays an integral role in facilitating the establishment of Sodalis-allied symbionts in diverse insect hosts. This knowledge contributes to the understanding of the early evolutionary steps involved in the formation of insect-bacterial symbiosis. Further, despite having no established history of interaction with tsetse, S. praecaptivus can infect reproductive tissues, enabling vertical transmission through adenotrophic viviparity within a single host generation. This creates an option for the use of S. praecaptivus in the biocontrol of insect disease vectors via paratransgenesis.


Assuntos
Percepção de Quorum/genética , Moscas Tsé-Tsé/genética , Fatores de Virulência/genética , 4-Butirolactona/análogos & derivados , 4-Butirolactona/biossíntese , 4-Butirolactona/genética , Animais , Enterobacteriaceae/genética , Enterobacteriaceae/patogenicidade , Humanos , Insetos Vetores/genética , Insetos Vetores/microbiologia , Insetos/genética , Simbiose/genética , Moscas Tsé-Tsé/microbiologia
14.
PLoS Negl Trop Dis ; 14(7): e0007489, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32658913

RESUMO

Phlebotomus papatasi sand flies inject their hosts with a myriad of pharmacologically active salivary proteins to assist with blood feeding and to modulate host defenses. In addition, salivary proteins can influence cutaneous leishmaniasis disease outcome, highlighting the potential of the salivary components to be used as a vaccine. Variability of vaccine targets in natural populations influences antigen choice for vaccine development. Therefore, the objective of this study was to investigate the variability in the predicted protein sequences of nine of the most abundantly expressed salivary proteins from field populations, testing the hypothesis that salivary proteins appropriate to target for vaccination strategies will be possible. PpSP12, PpSP14, PpSP28, PpSP29, PpSP30, PpSP32, PpSP36, PpSP42, and PpSP44 mature cDNAs from field collected P. papatasi from three distinct ecotopes in the Middle East and North Africa were amplified, sequenced, and in silico translated to assess the predicted amino acid variability. Two of the predicted sequences, PpSP12 and PpSP14, demonstrated low genetic variability across the three geographic isolated sand fly populations, with conserved multiple predicted MHCII epitope binding sites suggestive of their potential application in vaccination approaches. The other seven predicted salivary proteins revealed greater allelic variation across the same sand fly populations, possibly precluding their use as vaccine targets.


Assuntos
Proteínas de Insetos/genética , Insetos Vetores/genética , Phlebotomus/genética , Proteínas e Peptídeos Salivares/genética , Sequência de Aminoácidos , Animais , Sequência de Bases , Egito , Humanos , Proteínas de Insetos/imunologia , Insetos Vetores/imunologia , Jordânia , Phlebotomus/imunologia , Proteínas e Peptídeos Salivares/imunologia , Alinhamento de Sequência
15.
Parasitol Res ; 119(10): 3305-3313, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32651636

RESUMO

The genetic structure of natural populations offers insight into the complexities of their dynamics, information that can be relevant to vector control strategies. Microsatellites are useful neutral markers to investigate the genetic structure and gene flow in Triatoma infestans, one of the main vectors of Chagas disease in South America. Recently, a heterogeneous pyrethroid-resistant hotspot was found in the Argentine Gran Chaco, characterized by the highest levels of deltamethrin resistance found at the present time. We applied population genetics analyses to microsatellite and village data and search for associations between the genetic variability and the heterogeneous toxicological pattern previously found. We genotyped 10 microsatellite loci in 67 T. infestans from 6 villages with no, low, and high pyrethroid resistance. The most genetically diverse populations were those susceptible or with low values of resistance. In contrast, high-resistance populations had lower herozygosity and some monomorphic loci. A negative association was found between variability and resistant ratios. Global and pairwise FSTs indicated significant differentiation between populations. The only susceptible population was discriminated in all the performed studies. Low-resistance populations were also differentiated by a discriminant analysis of principal components (DAPC) and were composed mostly by the same two genetic clusters according to STRUCTURE Bayesian algorithm. Individuals from the high-resistance populations were overlapped in the DAPC and shared significant proportions of a genetic cluster. These observations suggest that the resistant populations might have a common origin, although more genetic markers and samples are required to test this hypothesis more rigorously.


Assuntos
Insetos Vetores/genética , Resistência a Inseticidas/genética , Inseticidas/farmacologia , Nitrilas/farmacologia , Piretrinas/farmacologia , Triatoma/genética , Animais , Argentina/epidemiologia , Doença de Chagas/epidemiologia , Doença de Chagas/transmissão , Variação Genética , Repetições de Microssatélites/genética
16.
PLoS Genet ; 16(7): e1008856, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32614824

RESUMO

The microRNAs (miRNAs) are important regulators of gene expression. In this study, we provide evidence for the first time to show that rickettsial pathogen Anaplasma phagocytophilum infection results in the down-regulation of tick microRNA-133 (miR-133), to induce Ixodes scapularis organic anion transporting polypeptide (isoatp4056) gene expression critical for this bacterial survival in the vector and for its transmission to the vertebrate host. Transfection studies with recombinant constructs containing transcriptional fusions confirmed binding of miR-133 to isoatp4056 mRNA. Treatment with miR-133 inhibitor resulted in increased bacterial burden and isoatp4056 expression in ticks and tick cells. In contrast, treatment with miR-133 mimic or pre-mir-133 resulted in dramatic reduction in isoatp4056 expression and bacterial burden in ticks and tick cells. Moreover, treatment of ticks with pre-mir-133 affected vector-mediated A. phagocytophilum infection of murine host. These results provide novel insights to understand impact of modulation of tick miRNAs on pathogen colonization in the vector and their transmission to infect the vertebrate host.


Assuntos
Anaplasma phagocytophilum/genética , Interações Hospedeiro-Patógeno/genética , Ixodes/genética , MicroRNAs/genética , Anaplasma phagocytophilum/patogenicidade , Animais , Apoptose , Vetores de Doenças , Regulação da Expressão Gênica/genética , Genes Essenciais/genética , Humanos , Insetos Vetores/genética , Ixodes/patogenicidade , Camundongos , Transportadores de Ânions Orgânicos/genética , Peptídeos/genética , Transcriptoma/genética
17.
Sci Rep ; 10(1): 9418, 2020 06 10.
Artigo em Inglês | MEDLINE | ID: mdl-32523040

RESUMO

The Asian citrus psyllid (ACP; Diaphorina citri) is the vector of Candidatus Liberibacter asiaticus (CLas) that is associated with the devastating Huanglongbing (HLB; citrus greening disease). This pest of Asian origin has spread into the Americas and more recently into a few countries in East Africa. During recent surveys, suspect ACP adults and nymphs were recorded for the first time infesting citrus trees in southwest Nigeria. Morphological identification and DNA barcoding confirmed the samples to be D. citri. Analysis of the obtained sequences revealed that the ACP recorded in Nigeria clustered with other taxa in the previously identified B1 clade that consists of populations from different continents. The presence of the endosymbionts Ca. Carsonella ruddii and Ca. Profftella armatura in ACP from Nigeria was also confirmed by PCR and Sanger sequencing. The ACP individuals were assayed for the presence of CLaf, CLam and CLas by qPCR, but none of the insects tested positive for any of the Liberibacters. The prolific nature of ACP and the tropical climate prevailing in the citrus-producing areas of Nigeria and other West African countries may favor its rapid spread and population increase, thus posing a grave threat to the sustainability of citriculture in these countries.


Assuntos
Citrus/parasitologia , Hemípteros/genética , Espécies Introduzidas , Doenças das Plantas/parasitologia , África Oriental , África Ocidental , Animais , Insetos Vetores/genética , Nigéria , Ninfa/genética , Reação em Cadeia da Polimerase em Tempo Real/métodos , Rhizobiaceae/genética
18.
Acta Trop ; 209: 105530, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32439318

RESUMO

Rhodnius ecuadoriensis is one of the most important vector species of Chagas disease in Ecuador. This species is distributed in the Central coast region and in the south Andean region, and an incipient speciation process between these geographical populations was previously proposed. The current population genetics study only focused on the Central coast region and analyzed 96 sylvatic specimens of R. ecuadoriensis associated with Phytelephas aequatorialis palm trees. We used Cytb and 16S-rRNA sequences and a Cytb-16S-rRNA concatenated set to explore (i) the genetic variability, spatial structuring, and demographic history of R. ecuadoriensis, and to determine (ii) the relationship between the genetic and climatic variabilities. A particularly high genetic variability was observed without detectable general genetic structure; only some terminal genetic clusters were observed. We did not observe isolation by geographical distance (IBD), and it is likely that ancient expansion occurred, according to Fs index and mismatch distribution for Cytb-16S-rRNA concatenated sequences. Hierarchical clustering showed that the current locality origins of the bugs were grouped into four bioclimatic clusters. Genetic and bioclimatic distances were not correlated, but some genetic clusters were associated with bioclimatic ones. The results showed an ancient evolution of the species in the region with a possible old expansion. The absence of spatial genetic structure could be due to climatic conditions (possible selection of singular genotypes) and to passive transportation of palms tree materials where R. ecuadoriensis are living.


Assuntos
Doença de Chagas/transmissão , Insetos Vetores/genética , Rhodnius/genética , Clima Tropical , Animais , Variação Genética
19.
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
20.
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
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