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1.
BMC Infect Dis ; 21(1): 269, 2021 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-33731042

RESUMO

BACKGROUND: Cutaneous leishmaniasis (CL), a neglected tropical disease, represents a significant public health problem in many endemic countries including Yemen. The ongoing armed conflict that started in March 2015 has had a negative impact on the entire healthcare system as well as on infectious disease control programmes. Therefore, this cross-sectional study aimed to assess knowledge and attitude towards CL among rural endemic communities in southwestern Yemen. METHODS: Five hundred households in five areas of Shara'b district of Taiz governorate were randomly selected to participate in a quantitative survey. A pretested structured questionnaire was used to collect data on the sociodemographic characteristics of the participants, their knowledge and attitude towards CL and their knowledge on the sand fly vector. RESULTS: The analysis was conducted on a final sample of 466 individuals (62.7% males and 37.3% females) aged between 18 and 70 years. Among the participants, 21.5% were non-educated while 39.7 and 20.8% had completed secondary school and tertiary education, respectively. Although the participants were aware of CL, about three quarters (77.7%) of them had poor overall knowledge about disease transmission, clinical presentation, treatment, and prevention. Interestingly, approximately half of the participants (49.1%) were able to differentiate sand flies from other flies and mosquitoes. However, only 14.8% of the participants knew about the role of the phlebotomine sand fly in the transmission of CL. Only 36.6% believed that CL can be prevented and 49.6% had a negative attitude towards the disease. Univariate and multivariate analyses showed that age and gender were the significant determinants of knowledge about CL and the sand fly vector among the studied population. CONCLUSION: A poor level of knowledge about the different epidemiological aspects of CL was found among rural CL-endemic communities in Taiz. This factor, together with the major collapse of the healthcare infrastructure due to the ongoing civil war in Yemen, may be contributing to the continued endemicity of CL in the governorate. It is therefore recommended that health education on CL transmission and prevention should be provided to the targeted communities.


Assuntos
Conhecimentos, Atitudes e Prática em Saúde , Leishmaniose Cutânea/epidemiologia , População Rural/estatística & dados numéricos , Adolescente , Adulto , Idoso , Animais , Estudos Transversais , Feminino , Humanos , Insetos Vetores/fisiologia , Leishmaniose Cutânea/prevenção & controle , Leishmaniose Cutânea/transmissão , Masculino , Pessoa de Meia-Idade , Psychodidae/fisiologia , Inquéritos e Questionários , Iêmen/epidemiologia , Adulto Jovem
2.
BMC Plant Biol ; 21(1): 67, 2021 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-33514310

RESUMO

BACKGROUND: Most plant viruses rely on vectors for their transmission and spread. One of the outstanding biological questions concerning the vector-pathogen-symbiont multi-trophic interactions is the potential involvement of vector symbionts in the virus transmission process. Here, we used a multi-factorial system containing a non-persistent plant virus, cucumber mosaic virus (CMV), its primary vector, green peach aphid, Myzus persicae, and the obligate endosymbiont, Buchnera aphidicola to explore this uncharted territory. RESULTS: Based on our preliminary research, we hypothesized that aphid endosymbiont B. aphidicola can facilitate CMV transmission by modulating plant volatile profiles. Gene expression analyses demonstrated that CMV infection reduced B. aphidicola abundance in M. persicae, in which lower abundance of B. aphidicola was associated with a preference shift in aphids from infected to healthy plants. Volatile profile analyses confirmed that feeding by aphids with lower B. aphidicola titers reduced the production of attractants, while increased the emission of deterrents. As a result, M. persicae changed their feeding preference from infected to healthy plants. CONCLUSIONS: We conclude that CMV infection reduces the B. aphidicola abundance in M. persicae. When viruliferous aphids feed on host plants, dynamic changes in obligate symbionts lead to a shift in plant volatiles from attraction to avoidance, thereby switching insect vector's feeding preference from infected to healthy plants.


Assuntos
Afídeos/virologia , Buchnera/fisiologia , Capsicum/virologia , Cucumovirus/fisiologia , Doenças das Plantas/virologia , Simbiose , Animais , Afídeos/efeitos dos fármacos , Afídeos/microbiologia , Afídeos/fisiologia , Capsicum/microbiologia , Capsicum/parasitologia , Comportamento Alimentar , Interações Hospedeiro-Parasita , Insetos Vetores/fisiologia , Doenças das Plantas/microbiologia , Doenças das Plantas/parasitologia , Rifampina/farmacologia , Compostos Orgânicos Voláteis/metabolismo
3.
Bull Entomol Res ; 111(2): 246-256, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33355061

RESUMO

The meadow spittlebug, Philaenus spumarius (L.) (Hemiptera: Aphrophoridae), is the main vector in Europe of the recently detected plant pathogen bacterium Xylella fastidiosa Wells et al. (Xanthomonadales: Xanthomonadaceae). While the ecology of continental populations is well documented, nothing is known about the insular populations of P. spumarius, such as in Corsica, where the bacterium was detected in 2015. Hence, in an epidemiological context, the ecology of P. spumarius has been studied in a maquis landscape in the Ajaccio region between 2017 and 2019. Adults and nymphs were almost exclusively collected on Cistus monspeliensis L. (Cistaceae). However, very few specimens were collected in summer, suggesting a movement of the adults to sheltered habitats. Unfortunately, despite several trapping methods used, the location of adult summer habitat remains unknown for the studied population. It might be tempting to destroy the central plant host of P. spumarius populations. However, as spittlebug nymphs are highly polyphagous on low-growing plant species and as the females can lay eggs in any dead plant tissues, such practice could have limited the impact. Instead, the strong relationship between P. spumarius and C. monspeliensis could be used to monitor spittlebug populations, to limit/concentrate the means of insect control, or in an agronomic context to lure insects away from crops. Maintaining natural arboreal vegetation around agronomic systems could help decrease insect abundance - and potentially, pathogen load - on cultivated species. Such hypotheses need to be further studied by landscape experiments.


Assuntos
Comportamento Alimentar , Hemípteros/fisiologia , Animais , Cistus , Produtos Agrícolas/microbiologia , Vetores de Doenças , Monitorização de Parâmetros Ecológicos , Ecossistema , França/epidemiologia , Hemípteros/microbiologia , Hiperfagia , Insetos Vetores/microbiologia , Insetos Vetores/fisiologia , Ninfa/fisiologia , Controle de Pragas/tendências , Doenças das Plantas/microbiologia , Estações do Ano , Especificidade da Espécie
4.
PLoS One ; 15(10): e0239771, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33022020

RESUMO

Huanglongbing (HLB) is a deadly, incurable citrus disease putatively caused by the unculturable bacterium, 'Candidatus Liberibacter asiaticus' (CLas), and transmitted by Diaphorina citri. Prior studies suggest D. citri transmits CLas in a circulative and propagative manner; however, the precise interactions necessary for CLas transmission remain unknown, and the impact of insect sex on D. citri-CLas interactions is poorly understood despite reports of sex-dependent susceptibilities to CLas. We analyzed the transcriptome, proteome, metabolome, and microbiome of male and female adult D. citri reared on healthy or CLas-infected Citrus medica to determine shared and sex-specific responses of D. citri and its endosymbionts to CLas exposure. More sex-specific than shared D. citri responses to CLas were observed, despite there being no difference between males and females in CLas density or relative abundance. CLas exposure altered the abundance of proteins involved in immunity and cellular and oxidative stress in a sex-dependent manner. CLas exposure impacted cuticular proteins and enzymes involved in chitin degradation, as well as energy metabolism and abundance of the endosymbiont 'Candidatus Profftella armatura' in both sexes similarly. Notably, diaphorin, a toxic Profftella-derived metabolite, was more abundant in both sexes with CLas exposure. The responses reported here resulted from a combination of CLas colonization of D. citri as well as the effect of CLas infection on C. medica. Elucidating these impacts on D. citri and their endosymbionts contributes to our understanding of the HLB pathosystem and identifies the responses potentially critical to limiting or promoting CLas acquisition and propagation in both sexes.


Assuntos
Citrus/microbiologia , Hemípteros/microbiologia , Insetos Vetores/microbiologia , Doenças das Plantas/microbiologia , Rhizobiaceae/fisiologia , Rhizobiaceae/patogenicidade , Simbiose/fisiologia , Animais , Citrus/metabolismo , Citrus/fisiologia , Feminino , Hemípteros/metabolismo , Hemípteros/fisiologia , Insetos Vetores/metabolismo , Insetos Vetores/fisiologia , Masculino , Metaboloma/fisiologia , Microbiota/fisiologia , Estresse Oxidativo/fisiologia , Proteoma/metabolismo , Transcriptoma/fisiologia
5.
PLoS Negl Trop Dis ; 14(9): e0008712, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32970687

RESUMO

BACKGROUND: Several studies addressed changes on the insect vector behavior due to parasite infection, but little is known for triatomine bugs, vectors of Trypanosoma cruzi, the etiological agent of Chagas disease. We assessed infection rates and metacyclogenesis of T. cruzi (TcVI) in fifth-instar nymphs of Triatoma rubrovaria comparing with the primary vector Triatoma infestans. Also, biological parameters related to feeding-excretion behavior were evaluated aiming to identify which variables are most influenced by T. cruzi infection. METHODOLOGY/PRINCIPAL FINDINGS: Fifth-instar nymphs of T. rubrovaria and T. infestans were fed on mice infected with T. cruzi (TcVI). We compared the presence and the number of parasite evolutive forms in excreta of both triatomine species at 30, 60 and 90 days post-infection (dpi) with traditional statistical analyses. Moreover, both species were analyzed through generalized linear models and multinomial logistic regression hypotheses for seven behavioral parameters related to host-seeking and feeding-excretion. Triatoma rubrovaria and T. infestans had similar overall infection and metacyclogenesis rates of T. cruzi TcVI in laboratory conditions. Regarding vector behavior, we confirmed that the triatomine's tendency is to move away from the bite region after a blood meal, probably to avoid being noticed by the vertebrate host. Interspecific differences were observed on the volume of blood ingested and on the proportion of individuals that excreted after the blood meal, revealing the higher feeding efficiency and dejection rates of T. infestans. The amount of ingested blood and the bite behavior of T. rubrovaria seems to be influenced by TcVI infection. Infected specimens tended to ingest ~25% more blood and to bite more the head of the host. Noteworthy, in two occasions, kleptohematophagy and coprophagy behaviors were also observed in T. rubrovaria. CONCLUSIONS/SIGNIFICANCE: Laboratory infections revealed similar rate of T. cruzi TcVI trypomatigotes in excreta of T. rubrovaria and T. infestans, one of the most epidemiological important vectors of T. cruzi. Therefore, TcVI DTU was able to complete its life cycle in T. rubrovaria under laboratory conditions, and this infection changed the feeding behavior of T. rubrovaria. Considering these results, T. rubrovaria must be kept under constant entomological surveillance in Rio Grande do Sul, Brazil.


Assuntos
Comportamento Alimentar , Insetos Vetores/fisiologia , Insetos Vetores/parasitologia , Triatoma/fisiologia , Triatoma/parasitologia , Trypanosoma cruzi/fisiologia , Animais , Brasil , Doença de Chagas/transmissão , Modelos Animais de Doenças , Interações Hospedeiro-Parasita , Mordeduras e Picadas de Insetos , Modelos Logísticos , Camundongos , Ninfa , Eliminação Renal , Trypanosoma cruzi/patogenicidade
6.
PLoS Negl Trop Dis ; 14(9): e0008696, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32970689

RESUMO

Gambiense Human African Trypanosomiasis (g-HAT) is a neglected tropical disease caused by trypanosomes transmitted by tsetse flies. 70% of cases in 2019 (604/863) occurred in the Democratic Republic of Congo (DRC). The national programme for g-HAT elimination in DRC includes a large-scale deployment of Tiny Targets which attract and kill tsetse. This intervention is directed by vector-control specialists with small teams, moving in canoes, deploying Tiny Targets along riverbanks where tsetse concentrate. While the targets are deployed in communal areas, and the method is cheap and easy-to-use, local people have little involvement. This study aimed to evaluate if a community-led vector control programme was feasible in the context of DRC's g-HAT elimination programme. In 2017, a community-led intervention was implemented in three villages in the Kwilu province of DRC. This intervention was evaluated through an Action Research with qualitative data collected through 21 focus group discussions and 289 hours of observation. Also the geographical location and quality of each Tiny Targets were collected (total number deployed = 2429). This research revealed that community-based approach largely worked: people were motivated and proactive, showed a good application of the acquired knowledge resulting in an effective deployment of Tiny Targets. In addition, our study provided evidence that acceptability of the targets by the community can improve deployment quality by reducing target loss and damage. The approach was feasible in places where canoe-based teams could not reach. Against these advantages, a community-based approach was time-consuming and had to adapt to the seasonal and daily rhythms of the community. A community-based approach for tsetse control is technically feasible and recommended but limits to the speed and scale of the approach restraints its application as a standalone strategy in a large-scale national programme aiming to eliminate g-HAT in a short timeframe.


Assuntos
Controle de Insetos/métodos , Insetos Vetores , Doenças Negligenciadas/prevenção & controle , Animais , República Democrática do Congo/epidemiologia , Erradicação de Doenças , Estudos de Viabilidade , Feminino , Humanos , Insetos Vetores/parasitologia , Insetos Vetores/fisiologia , Masculino , Doenças Negligenciadas/parasitologia , Projetos Piloto , Trypanosoma , Tripanossomíase Africana/epidemiologia , Tripanossomíase Africana/transmissão , Moscas Tsé-Tsé/parasitologia , Moscas Tsé-Tsé/fisiologia
7.
PLoS One ; 15(9): e0238134, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32936796

RESUMO

Malaria is a life-threatening disease, caused by Apicomplexan parasites of the Plasmodium genus. The Anopheles mosquito is necessary for the sexual replication of these parasites and for their transmission to vertebrate hosts, including humans. Imaging of the parasite within the insect vector has been attempted using multiple microscopy methods, most of which are hampered by the presence of the light scattering opaque cuticle of the mosquito. So far, most imaging of the Plasmodium mosquito stages depended on either sectioning or surgical dissection of important anatomical sites, such as the midgut and the salivary glands. Optical projection tomography (OPT) and light sheet fluorescence microscopy (LSFM) enable imaging fields of view in the centimeter scale whilst providing micrometer resolution. In this paper, we compare different optical clearing protocols and present reconstructions of the whole body of Plasmodium-infected, optically cleared Anopheles stephensi mosquitoes and their midguts. The 3D-reconstructions from OPT imaging show detailed features of the mosquito anatomy and enable overall localization of parasites in midguts. Additionally, LSFM imaging of mosquito midguts shows detailed distribution of oocysts in extracted midguts. This work was submitted as a pre-print to bioRxiv, available at https://www.biorxiv.org/content/10.1101/682054v2.


Assuntos
Anopheles/fisiologia , Imageamento Tridimensional , Insetos Vetores/fisiologia , Microscopia de Fluorescência , Plasmodium/fisiologia , Tomografia Óptica , Animais , Anopheles/parasitologia
8.
PLoS One ; 15(9): e0238198, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32946444

RESUMO

Visceral leishmaniasis (VL) is an infectious disease caused by the protozoa Leishmania chagasi, whose main vector in South America is Lutzomyia longipalpis. The disease was diagnosed in the Brazilian state of Espírito Santo (ES) for the first time in 1968. Currently, this disease has been considered endemic in 10 municipalities. Furthermore, the presence of L. longipalpis has been detected in eight other municipalities where the transmission has not been reported thus far. In this study, we performed species distribution modeling (SDM) to identify new and most likely receptive areas for VL transmission in ES. The sandflies were both actively and passively collected in various rural area of ES between 1986 and 2017. The collection points were georeferenced using a global positioning system device. Climatic data were retrieved from the WorldClim database, whereas geographic data were obtained from the National Institute for Space Research and the Integrated System of Geospatial Bases of the State of Espírito Santo. The maximum entropy algorithm was used through the MIAmaxent R package to train and test the distribution models for L. longipalpis. The major contributor to model generation was rocky outcrops, followed by temperature seasonality. The SDM predicted the expansion of the L. longipalpis-prone area in the Doce River Valley and limited the probability of expanding outside its watershed. Once the areas predicted suitable for L. longipalpis occurrence are determined, we can avoid the inefficient use of public resources in conducting canine serological surveys where the vector insect does not occur.


Assuntos
Clima , Geografia , Insetos Vetores/fisiologia , Leishmaniose Visceral/transmissão , Psychodidae/fisiologia , Animais , Brasil , Modelos Estatísticos , Análise Espacial
9.
Parasitol Res ; 119(9): 2775-2781, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32737590

RESUMO

Triatoma platensis is occasionally found coexisting with Triatoma infestans in chicken coops in Argentina. Some authors have reported the presence of hybrid specimens of both species in chicken coops and other peridomestic habitats. Given the coexistence of T. infestans with T. platensis and the possibility of generating fertile hybrids, it is important to evaluate the vectorial competence of these hybrids. The objective of this study was to record the dynamics of feeding-defecation behavior in fifth-stage nymphs and adults of hybrids between both species and to compare it with T. platensis and T. infestans. Three experimental groups were formed separated by stage and sex: Hybrid group, T. infestans group, and T. platensis group. During feeding, the following variables were recorded for each group: (i) blood meal size, (ii) feeding time, (iii) number of defecations during feeding, and (iv) number of defecations at 10 and 30 min after feeding. The results indicate that adults and fifth-instar nymphs of hybrids have a feeding and defecation behavior similar to T. infestans: they achieve feeding in a short time and first defecation occurs during or just after feeding. Nevertheless, hybrid's ingestion of blood occurs at higher velocity and they require higher blood intake to provoke early defecations. Considering the blood ingestion velocity, the amount of blood ingested, and the short time required for the production of the first defecation, the results of this study suggest that hybrid can be a competent Trypanosoma cruzi vector.


Assuntos
Defecação/fisiologia , Comportamento Alimentar/fisiologia , Insetos Vetores/fisiologia , Triatoma/fisiologia , Animais , Argentina , Doença de Chagas/transmissão , Galinhas/parasitologia , Ecossistema , Fezes/parasitologia , Feminino , Masculino , Ninfa/crescimento & desenvolvimento , Trypanosoma cruzi/crescimento & desenvolvimento
10.
PLoS Negl Trop Dis ; 14(7): e0008404, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32687497

RESUMO

The northeastern semiarid region stands out in the Brazilian context regarding the eco-epidemiology of Chagas disease, in which Triatoma brasiliensis is the main vector of Trypanosoma cruzi. Persistent house invasion threatens the relative levels of progress achieved over previous decades. We conducted an intervention trial with a five-year follow-up to assess the impacts of residual spraying with pyrethroid insecticides on house infestation with T. brasiliensis in 18 rural villages (242 houses) located in the Tauá, Ceará. House infestations were assessed by systematic manual searches for triatomines in every domestic and peridomestic habitat on five occasions. Triatomines were collected in peridomestic (57.5%), sylvatic (35.8%), and intradomiciliary (6.7%) habitats. The most important ecotopes of T. brasiliensis were containing roofing tiles, bricks or rocks (23.4% ± 9.1). Residual insecticide spraying substantially reduced baseline house infestation rates from 27.9% to 5.9% by 6 months post first spraying (MPS). The decline was substantially greater in intradomiciles (11.2% to 0.8%) than in peridomiciles (16.7% to 5%). The mean relative density of triatomines recovered its preintervention values at 14 MPS in intradomiciles, and in the main peridomestic ecotopes. The house infestation levels recorded at 14 MPS persisted thereafter despite all reinfested houses were selectively sprayed on every occasion. Overall average bug infection rates with T. cruzi in the five occasions were in intradomiciles (11.1%), peridomiciles (4.7%) and wild habitats (3.3%). In peridomicile T. cruzi infection rates decreased significantly at all stages after chemical intervention. In intradomicile, the only significant difference occurred at 20 MPS (7.7% to 30.8%). The vectorial capacity of T. brasiliensis, combined with its invasive potential from sylvatic sources and the limited effectiveness of chemical control in the harsh caatinga landscape, pose serious obstacles to the definite elimination of domestic transmission risks. Systematic vector surveillance supported by community participation and locally adapted environmental management measures are needed to reduce the risks of establishment of domestic transmission with T. cruzi in this region.


Assuntos
Controle de Insetos/métodos , Insetos Vetores/efeitos dos fármacos , Inseticidas/farmacologia , Triatoma/efeitos dos fármacos , Distribuição Animal , Animais , Brasil , Habitação , Humanos , Insetos Vetores/fisiologia , Piretrinas/farmacologia , Saúde da População Rural , Triatoma/fisiologia
11.
Mem Inst Oswaldo Cruz ; 115: e200070, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32667462

RESUMO

BACKGROUND Nyssorhynchus deaneorum is a potential malaria vector because it has been shown to be competent to transmit Plasmodium vivax and Plasmodium falciparum, and because it exhibits antropophilic and endophilic behaviors in some regions of the Amazon. This profile makes Ny. deaneorum a useful mosquito for experiments that model Plasmodium-vector interactions in the Amazon. OBJECTIVE Herein we describe how a free-mating colony of Ny. deaneorum has been established using an automated light stimulation system. METHODS Mosquitoes were captured in São Francisco do Guaporé, Rondônia. The F1 generation was reared until adult emergence at which point copulation was induced using an automatic copulation induction system (ACIS). FINDINGS After four generations, natural mating and oviposition began to occur without light stimulation. The number of pupae and adult mosquitoes increased from the F5 to F10 generations. The new Ny. deaneorum colony exhibited susceptibility to P. vivax. MAIN CONCLUSIONS Automated light stimulation is an effective method for establishing an Ny. deaneorum colony under laboratory conditions as it produces enough adults to create a stenogamic colony. The establishment of a stable, P. vivax-susceptible colony of Ny. deaneorum makes it possible to model parasite-vector interactions and to test novel drug therapies that target parasite development in mosquitoes.


Assuntos
Anopheles/parasitologia , Copulação/fisiologia , Malária , Mosquitos Vetores/parasitologia , Oviposição , Animais , Anopheles/fisiologia , Brasil , Feminino , Insetos Vetores/crescimento & desenvolvimento , Insetos Vetores/fisiologia , Plasmodium falciparum , Plasmodium vivax
12.
Parasitol Res ; 119(10): 3517-3522, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32617725

RESUMO

The parasite-vector interaction of Chagas disease is still poorly understood and the understanding of this relationship can help in the development of new strategies to control Trypanosoma cruzi transmission, which is the etiological agent of this disease. Considering the need to know if T. cruzi can cause some pathology in the reproductive system of the Chagas disease vectors, we investigated the spermatogenesis of Triatoma infestans infected by T. cruzi through histological and cytogenetic analysis. Trypanosoma cruzi Bolivia strain infection was not pathogenic for the reproductive system of T. infestans, because all the analyzed males had normal spermatogenesis, with all phases (spermatocytogenesis, meiosis and spermiogenesis) happening without any change. Thus, we demonstrated that the presence of T. cruzi Bolivia strain does not have influence in the spermatogenesis of T. infestans and we suggest that the influences on reproductive system observed for other species were a result of the action of the parasite on gametogenesis of females.


Assuntos
Doença de Chagas/transmissão , Insetos Vetores/parasitologia , Espermatogênese/fisiologia , Triatoma/parasitologia , Trypanosoma cruzi/fisiologia , Animais , Doença de Chagas/parasitologia , Interações Hospedeiro-Parasita , Insetos Vetores/fisiologia , Masculino , Triatoma/fisiologia
14.
PLoS One ; 15(4): e0232363, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32353044

RESUMO

Xylella fastidiosa pauca ST53 is the bacterium responsible for the Olive Quick Decline Syndrome that has killed millions of olive trees in Southern Italy. A recent work demonstrates that a rational integration of vector and transmission control measures, into a strategy based on chemical and physical control means, can manage Xylella fastidiosa invasion and impact below an acceptable economic threshold. In the present study, we propose a biological alternative to the chemical control action, which involves the predetermined use of an available natural enemy of Philaenus spumarius, i.e., Zelus renardii, for adult vector population and infection biocontrol. The paper combines two different approaches: a laboratory experiment to test the predation dynamics of Zelus renardii on Philaenus spumarius and its attitude as candidate for an inundation strategy; a simulated experiment of inundation, to preliminary test the efficacy of such strategy, before eventually proceeding to an in-field experimentation. With this double-fold approach we show that an inundation strategy with Zelus renardii has the potential to furnish an efficient and "green" solution to Xylella fastidiosa invasion, with a reduction of the pathogen incidence below 10%. The biocontrol model presented here could be promising for containing the impact and spread of Xylella fastidiosa, after an in-field validation of the inundation technique. Saving the fruit orchard, the production and the industry in susceptible areas could thus become an attainable goal, within comfortable parameters for sustainability, environmental safety, and effective plant health protection in organic orchard management.


Assuntos
Hemípteros/microbiologia , Insetos Vetores/microbiologia , Olea/microbiologia , Controle Biológico de Vetores/métodos , Doenças das Plantas/prevenção & controle , Xylella/patogenicidade , Animais , Hemípteros/patogenicidade , Hemípteros/fisiologia , Insetos Vetores/patogenicidade , Insetos Vetores/fisiologia , Olea/parasitologia , Comportamento Predatório
15.
Virology ; 546: 98-108, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32452421

RESUMO

Two members of the genus Capulavirus (Geminiviridae) are transmitted by aphids including Alfalfa leaf curl virus (ALCV) transmitted by Aphis craccivora. The capulavirus Euphorbia caput-medusae latent virus was shown here to be transmitted also by A. craccivora, using the population EuphorbiaSA. ALCV was transmissible by several A. craccivora populations including Robinia, but not the EuphorbiaSA population, reflecting a high transmission specificity. Typical of the circulative-persistent mode of transmission, ALCV persists through insect molts. ALCV accumulation and localization were analyzed in whole insects, midguts, hemolymphs, and heads of aphids from vector and non-vector populations of A. craccivora and from the non-vector species Acyrthosiphon pisum. Vector and non-vector populations could be distinguished by contrasted virus accumulations and midgut intracellular localization consistent with a gut barrier to the transmission of ALCV in A. pisum and a primary salivary gland barrier in A. craccivora.


Assuntos
Afídeos/virologia , Geminiviridae/fisiologia , Insetos Vetores/virologia , Medicago sativa/virologia , Doenças das Plantas/virologia , Animais , Afídeos/fisiologia , Geminiviridae/classificação , Geminiviridae/genética , Geminiviridae/isolamento & purificação , Insetos Vetores/fisiologia , Filogenia , Especificidade da Espécie
16.
Am J Trop Med Hyg ; 103(2): 619-624, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32342854

RESUMO

Bed bugs (Cimex spp.) are common ectoparasites of humans. Their ubiquity across diverse human environments combined with their blood-feeding behavior creates an ideal interface for the transmission of pathogenic microbes. Despite this potential, the current dogma is that bed bugs are not vectors of any known infectious agents. However, this conclusion is based largely on the results of studies conducted before the advent of modern molecular biology and the resurgence of bed bugs on a global scale. More importantly, a small but compelling body of modern research suggesting that bed bugs can potentially vector some human pathogens exists but is often overlooked. This article critically examines the current classification of the bed bug as an insect that does not transmit disease agents. In doing so, it highlights key knowledge gaps that still exist in understanding the potential of bed bugs as pathogen vectors and outlines several arguments for why new research on the topic is necessary.


Assuntos
Percevejos-de-Cama/microbiologia , Transmissão de Doença Infecciosa , Insetos Vetores/microbiologia , Animais , Percevejos-de-Cama/fisiologia , Humanos , Insetos Vetores/fisiologia
17.
PLoS Pathog ; 16(4): e1008440, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32294143

RESUMO

In flea-borne plague, blockage of the flea's foregut by Yersinia pestis hastens transmission to the mammalian host. Based on microscopy observations, we first suggest that flea blockage results from primary infection of the foregut and not from midgut colonization. In this model, flea infection is characterized by the recurrent production of a mass that fills the lumen of the proventriculus and encompasses a large number of Y. pestis. This recurrence phase ends when the proventricular cast is hard enough to block blood ingestion. We further showed that ymt (known to be essential for flea infection) is crucial for cast production, whereas the hmsHFRS operon (known to be essential for the formation of the biofilm that blocks the gut) is needed for cast consolidation. By screening a library of mutants (each lacking a locus previously known to be upregulated in the flea gut) for biofilm formation, we found that rpiA is important for flea blockage but not for colonization of the midgut. This locus may initially be required to resist toxic compounds within the proventricular cast. However, once the bacterium has adapted to the flea, rpiA helps to form the biofilm that consolidates the proventricular cast. Lastly, we used genetic techniques to demonstrate that ribose-5-phosphate isomerase activity (due to the recent gain of a second copy of rpiA (y2892)) accentuated blockage but not midgut colonization. It is noteworthy that rpiA is an ancestral gene, hmsHFRS and rpiA2 were acquired by the recent ancestor of Y. pestis, and ymt was acquired by Y. pestis itself. Our present results (i) highlight the physiopathological and molecular mechanisms leading to flea blockage, (ii) show that the role of a gene like rpiA changes in space and in time during an infection, and (iii) emphasize that evolution is a gradual process punctuated by sudden jumps.


Assuntos
Insetos Vetores/microbiologia , Peste/transmissão , Sifonápteros/microbiologia , Yersinia pestis/fisiologia , Animais , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Biofilmes , Sistema Digestório/microbiologia , Feminino , Humanos , Insetos Vetores/fisiologia , Masculino , Camundongos , Óperon , Peste/microbiologia , Sifonápteros/fisiologia , Yersinia pestis/genética
18.
Nat Commun ; 11(1): 1184, 2020 03 04.
Artigo em Inglês | MEDLINE | ID: mdl-32132537

RESUMO

Vector-borne pathogens are known to alter the phenotypes of their primary hosts and vectors, with implications for disease transmission as well as ecology. Here we show that a plant virus, barley yellow dwarf virus, increases the surface temperature of infected host plants (by an average of 2 °C), while also significantly enhancing the thermal tolerance of its aphid vector Rhopalosiphum padi (by 8 °C). This enhanced thermal tolerance, which was associated with differential upregulation of three heat-shock protein genes, allowed aphids to occupy higher and warmer regions of infected host plants when displaced from cooler regions by competition with a larger aphid species, R. maidis. Infection thereby led to an expansion of the fundamental niche of the vector. These findings show that virus effects on the thermal biology of hosts and vectors can influence their interactions with one another and with other, non-vector organisms.


Assuntos
Afídeos/fisiologia , Hordeum/virologia , Insetos Vetores/fisiologia , Luteovirus/patogenicidade , Termotolerância/genética , Distribuição Animal , Animais , Afídeos/virologia , Comportamento Alimentar/psicologia , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Proteínas de Choque Térmico/metabolismo , Resposta ao Choque Térmico/genética , Interações entre Hospedeiro e Microrganismos/genética , Temperatura Alta/efeitos adversos , Proteínas de Insetos/metabolismo , Doenças das Plantas/virologia
19.
PLoS Negl Trop Dis ; 14(3): e0007719, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32126087

RESUMO

The putative vector of trachoma, Musca sorbens, prefers to lay its eggs on human faeces on the ground. This study sought to determine whether M. sorbens females were attracted to volatile odours from human faeces in preference to odours from the faeces of other animals, and to determine whether specific volatile semiochemicals mediate selection of the faeces. Traps baited with the faeces of humans and local domestic animals were used to catch flies at two trachoma-endemic locations in The Gambia and one in Ethiopia. At all locations, traps baited with faeces caught more female M. sorbens than control traps baited with soil, and human faeces was the most successful bait compared with soil (mean rate ratios 44.40, 61.40, 10.50 [P<0.001]; 8.17 for child faeces [P = 0.004]). Odours from human faeces were sampled by air entrainment, then extracts of the volatiles were tested by coupled gas chromatography-electroantennography with laboratory-reared female M. sorbens. Twelve compounds were electrophysiologically active and tentatively identified by coupled mass spectrometry-gas chromatography, these included cresol, indole, 2-methylpropanoic acid, butanoic acid, pentanoic acid and hexanoic acid. It is possible that some of these volatiles govern the strong attraction of M. sorbens flies to human faeces. If so, a synthetic blend of these chemicals, at the correct ratios, may prove to be a highly attractive lure. This could be used in odour-baited traps for monitoring or control of this species in trachoma-endemic regions.


Assuntos
Fezes/química , Insetos Vetores/efeitos dos fármacos , Muscidae/efeitos dos fármacos , Feromônios/farmacologia , Compostos Orgânicos Voláteis/farmacologia , Adolescente , Adulto , Animais , Criança , Cromatografia Gasosa , Fenômenos Eletrofisiológicos , Etiópia , Feminino , Gâmbia , Humanos , Insetos Vetores/fisiologia , Masculino , Muscidae/fisiologia , Feromônios/isolamento & purificação , Compostos Orgânicos Voláteis/isolamento & purificação , Adulto Jovem
20.
Sci Rep ; 10(1): 5116, 2020 03 20.
Artigo em Inglês | MEDLINE | ID: mdl-32198397

RESUMO

Acoustic communication in the form of courtship and mating songs are often involved in reproductive isolation between species of Diptera, such as Drosophila, mosquitoes and sand flies. The patterns of courtship songs in New World sand fly species evolve quickly under sexual selection; and therefore, represent an important trait that can be used as a marker to study the evolution of species complexes and may aid identification of sibling species with a complex. The ability to identify vector species within species complexes is of critical importance for effective and efficient vector control programs. Species-specific song patterns seems to contribute to reproductive isolation in New World sand fly species, suggesting that auditory communication signals may be widespread among these important vectors of leishmaniasis. The main goal of the present study was to characterize the copulatory courtship song of Phlebotomus argentipes, an important vector of visceral leishmaniasis in the Old World. Ph. argentipes males produce acoustic signals during copulation and two types of songs were observed. The one we called primary song is a 'pulse song' with similar length and amplitude to the previously observed 'P1' pattern recorded in Brazilian populations of Lu. longipalpis s.l. The secondary song has 'sine song' characteristics and is quite different from any song produced by New World species. The discovery of this copulation courtship songs in Ph. argentipes supports the possibility that acoustic communication in sandflies might be more widespread than previously thought, including Old World species. Our results highlight the importance of further research on acoustic communication in the Ph. argentipes species complex and other Old World vectors of leishmaniasis.


Assuntos
Corte , Phlebotomus/fisiologia , Isolamento Reprodutivo , Comportamento Sexual Animal/fisiologia , Vocalização Animal/fisiologia , Animais , Drosophila/fisiologia , Feminino , Insetos Vetores/parasitologia , Insetos Vetores/fisiologia , Masculino , Phlebotomus/parasitologia
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