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1.
Mem Inst Oswaldo Cruz ; 115: e200218, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32696917

RESUMEN

BACKGROUND: Southeast Brazil has recently experienced a Yellow Fever virus (YFV) outbreak where the mosquito Haemagogus leucocelaenus was a primary vector. Climatic factors influence the abundance of mosquito vectors and arbovirus transmission. OBJECTIVES: We aimed at describing the population dynamics of Hg. leucocelaenus in a county touched by the recent YFV outbreak. METHODS: Fortnightly egg collections with ovitraps were performed from November 2012 to February 2017 in a forest in Nova Iguaçu, Rio de Janeiro, Brazil. The effects of mean temperature and rainfall on the Hg. leucocelaenus population dynamics were explored. FINDINGS: Hg. leucocelaenus eggs were continuously collected throughout the study, with a peak in the warmer months (December-March). The climatic variables had a time-lagged effect and four weeks before sampling was the best predictor for the positivity of ovitraps and total number of eggs collected. The probability of finding > 50% positive ovitraps increased when the mean temperature was above 24ºC. The number of Hg. leucocelaenus eggs expressively increase when the mean temperature and accumulated precipitation surpassed 27ºC and 100 mm, respectively, although the effect of rainfall was less pronounced. MAIN CONCLUSIONS: Monitoring population dynamics of Hg. leucocelaenus and climatic factors in YFV risk areas, especially mean temperature, may assist in developing climate-based surveillance procedures to timely strengthening prophylaxis and control.


Asunto(s)
Culicidae/virología , Bosques , Insectos Vectores/virología , Dinámica Poblacional , Fiebre Amarilla , Virus de la Fiebre Amarilla/aislamiento & purificación , Animales , Brasil , Culicidae/clasificación , Insectos Vectores/clasificación , Estaciones del Año , Temperatura , Virus de la Fiebre Amarilla/genética
3.
PLoS Biol ; 18(6): e3000723, 2020 06.
Artículo en Inglés | MEDLINE | ID: mdl-32511224

RESUMEN

Lymphatic filariasis (LF) afflicts over 60 million people worldwide and leads to severe pathological outcomes in chronic cases. The nematode parasites (Nematoda: Filarioidea) that cause LF require both arthropod (mosquito) intermediate hosts and mammalian definitive hosts for their propagation. The invasion and migration of filarial worms through host tissues are complex and critical to survival, yet little is known about the receptors and signaling pathways that mediate directed migration in these medically important species. In order to better understand the role of chemosensory signaling in filarial worm taxis, we employ comparative genomics, transcriptomics, reverse genetics, and chemical approaches to identify putative chemosensory receptor proteins and perturb chemotaxis phenotypes in filarial worms. We find that chemoreceptor family size is correlated with the presence of environmental (extrahost) stages in nematode life cycles, and that filarial worms contain compact and highly diverged chemoreceptor complements and lineage-specific ion channels that are predicted to operate downstream of chemoreceptor activation. In Brugia malayi, an etiological agent of LF, chemoreceptor expression patterns correspond to distinct parasite migration events across the life cycle. To interrogate the role of chemosensation in the migration of larval worms, arthropod and mammalian infectious stage Brugia parasites were incubated in nicotinamide, an agonist of the nematode transient receptor potential (TRP) channel OSM-9. Exposure of microfilariae to nicotinamide alters intramosquito migration, and exposure of L3s reduces chemotaxis toward host-associated cues in vitro. Nicotinamide also potently modulates thermosensory responses in L3s, suggesting a polymodal sensory role for Brugia osm-9. Reverse genetic studies implicate both Brugia osm-9 and the cyclic nucleotide-gated (CNG) channel subunit tax-4 in larval chemotaxis toward host serum, and these ion channel subunits partially rescue sensory defects in Caenorhabditis elegans osm-9 and tax-4 knock-out strains. Together, these data reveal genetic and functional diversification of chemosensory signaling proteins in filarial worms and encourage a more thorough investigation of clade- and parasite-specific facets of nematode sensory receptor biology.


Asunto(s)
Brugia Malayi/genética , Células Quimiorreceptoras/metabolismo , Culicidae/parasitología , Filariasis Linfática/parasitología , Variación Genética , Animales , Caenorhabditis elegans/fisiología , Quimiotaxis , Genoma , Proteínas del Helminto/metabolismo , Larva , Estadios del Ciclo de Vida , Interferencia de ARN , ARN Bicatenario/metabolismo , Canales Catiónicos TRPV/agonistas , Canales Catiónicos TRPV/metabolismo , Temperatura
4.
PLoS One ; 15(5): e0232286, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32369525

RESUMEN

BACKGROUND: Creating National Sanitary City (CNSC) promotes appearance, environment sanitation and public health including vector management of cities in China. However, vector management especially mosquito management and the related administrative productivity of Patriotic Health Campaign System (PHCS) of National Sanitary Cities (NSCs) were questioned by many pest control professionals and citizens. In this study, we studied mosquito management of NSCs taking Wuhan as an example. The study aimed to (1) determine the distribution and abundance of immature mosquito habitats in built-up areas of Wuhan and (2) better understand the related administration procedure in CNSC. METHODS: Immature mosquito habitat surveillance was carried out in randomly selected premises of driving schools (DSs), schools or kindergartens (SKs), property management residential areas (PMRAs), construction sites (CSs), wide roads with storm drains (WRSDs) and urban creeks (UCs) in built-up areas of Wuhan from July to October 2015 followed by questionnaire interviews with one each of premise occupants and district departments responsible for mosquito management in these premises. RESULTS: Total of 64.1 km of route were inspected in 36 DSs, 36 SKs, 36 PMRAs, 36 CSs and 36 segments of WRSD and 2,158 potential mosquito habitats with 749 (35%) mosquito-positive habitats were found. The route index (RI) was 11.7, which was 14.6 times higher than the grade C criteria for vector density control (RI = 0.8 positive habitats/km) in CNSC. Occupants of 36 DSs, 36 SKs, 36 PMRAs, 34 CSs were interviewed and 77% of them reported no difference in mosquito infestation in their premises since 2013 and 80% of them knew about the responsibility and arrangements of PHCS of mosquito management in their premises. Only 15% had the awareness of larval source reduction strategy and 14% had implemented it. Receipt the electronic/paper edition of CNSC vector management specifications from the PHCS was very low (13%) and an official notification or bulletin for rectification mosquito-positive habitats was also very low (5%). Of the 75 responsible district departments interviewed, about half (55%) reported that they had held training courses/meetings related to CNSC vector management, the majority (96%) reported that they had not carried out independent on-site supervision of premises under their jurisdiction. No differences in larval indices were found between premises which were administrative intervened and with no administrative intervention. CONCLUSIONS: The administrative intervention of PHCS had not evidently improved mosquito management of the premises in built-up areas in Wuhan. It is a violation of the original intention of the National Patriotic Health Campaign Committee in organizing CNSC programs. To combat mosquito borne diseases, and to improve the quality of life of residents, we recommend that PHCS honestly reveals defects in urban mosquito management and seriously takes those exposed defects. The PHCS should strengthen Patriotic Health Campaign activities by strict adherence to NSC standards. Further research on sustained promotion of urban mosquito management of NSCs, which focus on effective administration, as well as on improvement of related sectors of NSC standards should be carried out.


Asunto(s)
Control de Mosquitos , Animales , China , Ciudades , Industria de la Construcción , Culicidae , Ecosistema , Humanos , Control de Mosquitos/métodos , Mosquitos Vectores , Salud Pública , Ríos , Instituciones Académicas , Encuestas y Cuestionarios , Transportes
5.
PLoS One ; 15(5): e0232585, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32374750

RESUMEN

Neurotropic flavivirus Japanese encephalitis virus (JEV) and West Nile virus (WNV) are amongst the leading causes of encephalitis. Using label-free quantitative proteomics, we identified proteins differentially expressed upon JEV (gp-3, RP9) or WNV (IS98) infection of human neuroblastoma cells. Data are available via ProteomeXchange with identifier PXD016805. Both viruses were associated with the up-regulation of immune response (IFIT1/3/5, ISG15, OAS, STAT1, IRF9) and the down-regulation of SSBP2 and PAM, involved in gene expression and in neuropeptide amidation respectively. Proteins associated to membranes, involved in extracellular matrix organization and collagen metabolism represented major clusters down-regulated by JEV and WNV. Moreover, transcription regulation and mRNA processing clusters were also heavily regulated by both viruses. The proteome of neuroblastoma cells infected by JEV or WNV was significantly modulated in the presence of mosquito saliva, but distinct patterns were associated to each virus. Mosquito saliva favored modulation of proteins associated with gene regulation in JEV infected neuroblastoma cells while modulation of proteins associated with protein maturation, signal transduction and ion transporters was found in WNV infected neuroblastoma cells.


Asunto(s)
Culicidae/metabolismo , Encefalitis Japonesa/metabolismo , Neuronas/patología , Proteoma/metabolismo , Fiebre del Nilo Occidental/metabolismo , Animales , Línea Celular Tumoral , Culicidae/virología , Virus de la Encefalitis Japonesa (Subgrupo)/aislamiento & purificación , Encefalitis Japonesa/patología , Encefalitis Japonesa/virología , Femenino , Humanos , Neuronas/metabolismo , Neuronas/virología , Proteoma/análisis , Saliva/metabolismo , Saliva/virología , Fiebre del Nilo Occidental/patología , Fiebre del Nilo Occidental/virología , Virus del Nilo Occidental/aislamiento & purificación
6.
Science ; 368(6491): 586-587, 2020 05 08.
Artículo en Inglés | MEDLINE | ID: mdl-32381708
7.
Science ; 368(6491): 634-637, 2020 05 08.
Artículo en Inglés | MEDLINE | ID: mdl-32381721

RESUMEN

Some flying animals use active sensing to perceive and avoid obstacles. Nocturnal mosquitoes exhibit a behavioral response to divert away from surfaces when vision is unavailable, indicating a short-range, mechanosensory collision-avoidance mechanism. We suggest that this behavior is mediated by perceiving modulations of their self-induced airflow patterns as they enter a ground or wall effect. We used computational fluid dynamics simulations of low-altitude and near-wall flights based on in vivo high-speed kinematic measurements to quantify changes in the self-generated pressure and velocity cues at the sensitive mechanosensory antennae. We validated the principle that encoding aerodynamic information can enable collision avoidance by developing a quadcopter with a sensory system inspired by the mosquito. Such low-power sensing systems have major potential for future use in safer rotorcraft control systems.


Asunto(s)
Accidentes de Aviación/prevención & control , Aeronaves , Culicidae/fisiología , Vuelo Animal/fisiología , Visión Nocturna/fisiología , Animales , Antenas de Artrópodos/fisiología , Biónica , Simulación por Computador , Robótica/métodos
8.
Nat Commun ; 11(1): 1764, 2020 04 09.
Artículo en Inglés | MEDLINE | ID: mdl-32273496

RESUMEN

Gametocytes differentiation to gametes (gametogenesis) within mosquitos is essential for malaria parasite transmission. Both reduction in temperature and mosquito-derived XA or elevated pH are required for triggering cGMP/PKG dependent gametogenesis. However, the parasite molecule for sensing or transducing these environmental signals to initiate gametogenesis remains unknown. Here we perform a CRISPR/Cas9-based functional screening of 59 membrane proteins expressed in the gametocytes of Plasmodium yoelii and identify that GEP1 is required for XA-stimulated gametogenesis. GEP1 disruption abolishes XA-stimulated cGMP synthesis and the subsequent signaling and cellular events, such as Ca2+ mobilization, gamete formation, and gametes egress out of erythrocytes. GEP1 interacts with GCα, a cGMP synthesizing enzyme in gametocytes. Both GEP1 and GCα are expressed in cytoplasmic puncta of both male and female gametocytes. Depletion of GCα impairs XA-stimulated gametogenesis, mimicking the defect of GEP1 disruption. The identification of GEP1 being essential for gametogenesis provides a potential new target for intervention of parasite transmission.


Asunto(s)
Culicidae/metabolismo , Gametogénesis/efectos de los fármacos , Membranas Intracelulares/metabolismo , Proteínas Protozoarias/metabolismo , Xanturenatos/farmacología , Animales , Sistemas CRISPR-Cas/genética , Calcio/metabolismo , Culicidae/parasitología , GMP Cíclico/metabolismo , Proteínas Quinasas Dependientes de GMP Cíclico/metabolismo , Edición Génica/métodos , Malaria/parasitología , Mosquitos Vectores/metabolismo , Mosquitos Vectores/parasitología , Plasmodium/genética , Plasmodium/metabolismo , Plasmodium/fisiología , Proteínas Protozoarias/genética , Xanturenatos/metabolismo
9.
PLoS Comput Biol ; 16(4): e1007446, 2020 04.
Artículo en Inglés | MEDLINE | ID: mdl-32320389

RESUMEN

Mosquitoes are important vectors for pathogens that infect humans and other vertebrate animals. Some aspects of adult mosquito behavior and mosquito ecology play an important role in determining the capacity of vector populations to transmit pathogens. Here, we re-examine factors affecting the transmission of pathogens by mosquitoes using a new approach. Unlike most previous models, this framework considers the behavioral states and state transitions of adult mosquitoes through a sequence of activity bouts. We developed a new framework for individual-based simulation models called MBITES (Mosquito Bout-based and Individual-based Transmission Ecology Simulator). In MBITES, it is possible to build models that simulate the behavior and ecology of adult mosquitoes in exquisite detail on complex resource landscapes generated by spatial point processes. We also developed an ordinary differential equation model which is the Kolmogorov forward equations for models developed in MBITES under a specific set of simplifying assumptions. While mosquito infection and pathogen development are one possible part of a mosquito's state, that is not our main focus. Using extensive simulation using some models developed in MBITES, we show that vectorial capacity can be understood as an emergent property of simple behavioral algorithms interacting with complex resource landscapes, and that relative density or sparsity of resources and the need to search can have profound consequences for mosquito populations' capacity to transmit pathogens.


Asunto(s)
Conducta Animal , Culicidae/fisiología , Malaria/transmisión , Mosquitos Vectores , Algoritmos , Animales , Biología Computacional , Simulación por Computador , Vectores de Enfermedades , Ecología , Ecosistema , Conducta Alimentaria , Femenino , Humanos , Masculino , Modelos Teóricos , Método de Montecarlo , Oviposición , Probabilidad
10.
Epidemiol Infect ; 148: e72, 2020 04 01.
Artículo en Inglés | MEDLINE | ID: mdl-32234110

RESUMEN

From 1971 to 2012, in New York State, years with human Eastern equine encephalitis (EEE) were more strongly associated with the presence of Aedes canadensis, Coquillettidia perturbans and Culiseta melanura mosquitoes infected with the EEE virus (Fisher's exact test, one-sided P = 0.005, 0.03, 0.03) than with Culiseta morsitans, Aedes vexans, Culex pipiens-restuans, Anopheles quadrimaculatus or Anopheles punctipennis (P = 0.05, 0.40, 0.33, 1.00, 1.00). The estimated relative risk of a case in a year in which the virus was detected vs. not detected was 14.67 for Ae. canadensis, 6.38 for Cq. perturbans and 5.50 for Cs. morsitans. In all 5 years with a case, Cs. melanura with the virus was detected. In no year was there a case in the absence of Cs. melanura with the virus. There were 18 years with no case in the presence of Cs. melanura with the virus. Such observations may identify the time of increased risk, and when the methods may be used to prevent or reduce exposure to vector mosquito species in this geographic region.


Asunto(s)
Culicidae/virología , Virus de la Encefalitis Equina del Este , Encefalomielitis Equina Oriental , Mosquitos Vectores/virología , Aedes/virología , Animales , Encefalomielitis Equina Oriental/epidemiología , Encefalomielitis Equina Oriental/transmisión , Encefalomielitis Equina Oriental/virología , Humanos , New York , Análisis Espacio-Temporal
11.
Am J Trop Med Hyg ; 102(5): 964-970, 2020 05.
Artículo en Inglés | MEDLINE | ID: mdl-32228777

RESUMEN

Two confirmed human cases of Zika virus (ZIKV) were reported in the district of Miri, Sarawak, in 2016. Following that, a mosquito-based ZIKV surveillance study was conducted within 200-m radius from the case houses. Mosquito surveillance was conducted using five different methods, that is, biogents sentinel mosquito (BG) sentinel trap, modified sticky ovitrap, resting catch, larval surveillance, and conventional ovitrap. A total of 527 and 390 mosquito samples were obtained from the case houses in two localities, namely, Kampung Lopeng and Taman Shang Ri La, Miri, Sarawak, respectively. All mosquitoes collected were identified, which consisted of 11 species. Aedes albopictus, both the adult and larval stages, was the dominant species. Resting catch method obtained the highest number of adult mosquitoes (67%), whereas ovitrap showed the highest catch for larval mosquitoes (84%). Zika virus was detected in both adults and larvae of Ae. albopictus together with adults of Culex gelidus, and Culex quinquefasciatus using the real-time reverse transcriptase polymerase chain reaction (PCR) technique. It was noteworthy that Ae. albopictus positive with ZIKV were caught and obtained from four types of collection method. By contrast, Cx. gelidus and Culex quinquefasciatus adults collected from sticky ovitraps were also found positive with ZIKV. This study reveals vital information regarding the potential vectors of ZIKV and the possibility of transovarian transmission of the virus in Malaysia. These findings will be essentials for vector control program managers to devise preparedness and contingency plans of prevention and control of the arboviral disease.


Asunto(s)
Culicidae/virología , Mosquitos Vectores/virología , Infección por el Virus Zika/epidemiología , Aedes/virología , Animales , Culex/virología , Femenino , Humanos , Malasia/epidemiología , Masculino , Vigilancia de la Población , Reacción en Cadena en Tiempo Real de la Polimerasa , Infección por el Virus Zika/etiología , Infección por el Virus Zika/transmisión
12.
PLoS Negl Trop Dis ; 14(4): e0008175, 2020 04.
Artículo en Inglés | MEDLINE | ID: mdl-32267840

RESUMEN

We recently developed a superhydrophobic cone-based method for the collection of mosquito excreta/feces (E/F) for the molecular xenomonitoring of vector-borne parasites showing higher throughput compared to the traditional approach. To test its field applicability, we used this platform to detect the presence of filarial and malaria parasites in two villages of Ghana and compared results to those for detection in mosquito carcasses and human blood. We compared the molecular detection of three parasites (Wuchereria bancrofti, Plasmodium falciparum and Mansonella perstans) in mosquito E/F, mosquito carcasses and human blood collected from the same households in two villages in the Savannah Region of the country. We successfully detected the parasite DNA in mosquito E/F from indoor resting mosquitoes, including W. bancrofti which had a very low community prevalence (2.5-3.8%). Detection in the E/F samples was concordant with detection in insect whole carcasses and human blood, and a parasite not vectored by mosquitoes was detected as well.Our approach to collect and test mosquito E/F successfully detected a variety of parasites at varying prevalence in the human population under field conditions, including a pathogen (M. perstans) which is not transmitted by mosquitoes. The method shows promise for further development and applicability for the early detection and surveillance of a variety of pathogens carried in human blood.


Asunto(s)
Culicidae/parasitología , ADN Protozoario/aislamiento & purificación , Heces/parasitología , Malaria/parasitología , Mosquitos Vectores/parasitología , Animales , ADN de Helmintos/genética , ADN Protozoario/genética , Composición Familiar , Ghana/epidemiología , Humanos , Malaria/epidemiología , Técnicas de Diagnóstico Molecular/métodos , Plasmodium falciparum/genética , Prevalencia , Wuchereria bancrofti/genética
13.
Zhonghua Liu Xing Bing Xue Za Zhi ; 41(4): 571-579, 2020 Apr 10.
Artículo en Chino | MEDLINE | ID: mdl-32344484

RESUMEN

Objective: To investigate the types and distribution of blood-sucking insects and arboviruses in Inner Mongolia autonomous region, and provide basic data for the prevention of arbovirus transmitted disease. Methods: Blood-sucking insects were collected by lamp trapping method in nature. Mosquito samples were classified according to morphologic characteristics and then stored at liquid nitrogen. Viruses were isolated in cell culture and characterized, using molecular biological methods. Results: A total of 24 240 mosquitoes and 17 110 aphids were collected from 2 sites of 5 counties (Flags) in Inner Mongolia in 2014 and during 2017-2018. Among them, Japanese encephalitis virus gene was detected in Culex pipiens pallens, and 4 virus strains isolates which could be stably passaged. The isolates were identified as Getah virus and densonucleosis virus by molecular biology identification. Phylogenetic analysis on the E2 gene of the Getah virus (NMDK1813-1) showed that it belonged to the same evolutionary branch of the Gansu isolates (GS10-2) and having six common amino acid variation sites. Conclusions: The emergence of Japanese encephalitis virus and Getah virus from specimen of mosquitoes in Inner Mongolia indicated the new challenges on the prevention and control of arbovirus and related diseases. The results pf this study provided basic data for the prevention and control stretagies of arbovirus transmitted diseases in Inner Mongolia.


Asunto(s)
Alphavirus/aislamiento & purificación , Culicidae/virología , Virus de la Encefalitis Japonesa (Especie)/genética , Virus de la Encefalitis Japonesa (Especie)/aislamiento & purificación , Encefalitis Japonesa , Mosquitos Vectores/virología , ARN Viral/genética , Animales , China , Filogenia , ARN Viral/aislamiento & purificación
14.
Rev Soc Bras Med Trop ; 53: e20190439, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32321091

RESUMEN

INTRODUCTION: DENV-2 is the cause of most dengue epidemics worldwide and is associated with severe cases. METHODS: We investigated arboviruses in 164 serum samples collected from patients presenting with clinical symptoms of dengue fever and 152 mosquito pools. RESULTS: We detected the Asian II genotype of DENV-2 in humans and mosquitoes. Our results confirmed the circulation of the Asian II genotype in Brazil, in addition to the prevalent Asian/American genotype. CONCLUSIONS: The detection of Asian II genotype of DENV-2 in mosquito pools collected in a forest park may be related to a spillback event of human dengue virus.


Asunto(s)
Culicidae/virología , Virus del Dengue/genética , Dengue/virología , Animales , Brasil , Culicidae/clasificación , Genotipo , Humanos , Filogenia , Reacción en Cadena de la Polimerasa , ARN Viral/genética , Estaciones del Año
15.
Zootaxa ; 4747(3): zootaxa.4747.3.1, 2020 Mar 04.
Artículo en Inglés | MEDLINE | ID: mdl-32230095

RESUMEN

The distributions of the Afrotropical Anopheles mosquitoes were first summarized in 1938. In 2017, an extensive geo-coded inventory was published for 48 sub-Saharan African countries, including information such as sampling methods, collection dates, geographic co-ordinates and the literature consulted to produce the database. Using the information from the 2017 inventory, earlier distribution lists, museum collections and publications since 2016, this paper presents an updated, simplified list of Anopheles species by mainland countries and associated Afrotropical islands, with comments where applicable. It is intended as a supplement to the 2017 geo-coded inventory.


Asunto(s)
Anopheles , Culicidae , Animales , Islas
16.
Zootaxa ; 4747(2): zootaxa.4747.2.8, 2020 Mar 03.
Artículo en Inglés | MEDLINE | ID: mdl-32230114

RESUMEN

Examination of type specimens and topotypic material is often a necessary step to ascertain the validity of a species. Consequently, solid knowledge about type series, type locality and type depository is critical. In this paper, we provide a thorough review of the mosquito species originally described from specimens collected in French Guiana, with specific emphasis on the location of the current depositories of type material, the composition of type series and the delimitation of type localities. Information already published about the mosquito type material from French Guiana was gathered and efforts were made to ascertain the current location of their depositories. This investigation made it possible to locate a large part of the existing type material and to provide corrected information on type series and type localities, therefore providing a strong basis for future taxonomic research on mosquitoes. The type locality of Culex (Culex) pseudojanthinosoma Senevet Abonnenc is corrected from French Guiana to Africa, and this species is synonymized with Culex (Culex) duttoni Theobald.


Asunto(s)
Culex , Culicidae , Animales , Guyana Francesa
17.
Zootaxa ; 4722(5): zootaxa.4722.5.5, 2020 Jan 16.
Artículo en Inglés | MEDLINE | ID: mdl-32230607

RESUMEN

The original description of Heizmannia (Heizmannia) metallica (Leicester) from Malaysia, and specimens collected in India that were provisionally identified as Hz. metallica, were re-examined for their taxonomic status. Heizmannia metallica from Malaysia was found by Mattingly (1970) to be a junior synonym of Hz. indica (Theobald), whereas we found the specimens identified as Hz. metallica from India to differ distinctly from the holotype of Hz. metallica. We collected adults near Malabar Coast, Western Ghats which corresponded with Indian Hz. metallica sensu auctorum and here describe the previously misidentified species as Hz. (Hez.) rajagopalani n. sp. The adult male and female of the new species, and their genitalia, are described and illustrated.


Asunto(s)
Culicidae , Animales , Femenino , Genitales , India , Masculino
18.
Mol Genet Genomics ; 295(4): 891-909, 2020 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-32189066

RESUMEN

Wolbachia is an obligate intracellular Gram-negative alpha-proteobacterium that has diverse effects on reproduction of arthropod hosts, including cytoplasmic incompatibility, male killing, feminization, and parthenogenesis. Some of these effects have important potential for control of insect pests, including mosquitoes that vector pathogens of humans. In mosquitoes, and in most other arthropods, elimination of Wolbachia by antibiotic treatment has no effect on host survival and reverses the Wolbachia-associated phenotype. Elimination of Wolbachia strain wFol, which enables parthenogenetic reproduction of the Collembolan, Folsomia candida, would result in population extinction. However, F. candida adults remain viable and resume reproduction when antibiotics are removed, suggesting that wFol survives antibiotic treatment in a quiescent persister state similar to that induced by chromosomally encoded toxin-antitoxin (TA) modules in free-living bacteria. Computational approaches were used to document the presence of antitoxin genes upstream of Wolbachia RelE/ParE, Fic, and AbiEii toxin genes. Moreover, this analysis revealed that Wolbachia RatA toxin is encoded by a single copy gene associated with an ssrS noncoding RNA gene. Documentation of potentially functional TA modules expands our understanding of the metabolic capabilities of Wolbachia, and provides an explanation for variable and sometimes contradictory results of antibiotic treatments. The presence of chromosomal TA modules in Wolbachia genomes suggests that wFol, and potentially other strains of Wolbachia, can enter a quiescent persister state.


Asunto(s)
Partenogénesis/genética , Reproducción/genética , Sistemas Toxina-Antitoxina/genética , Wolbachia/genética , Animales , Cromosomas Bacterianos/genética , Culicidae/microbiología , Topoisomerasa de ADN IV/genética , Genoma Bacteriano/genética , Humanos , Masculino , Control de Plagas , Simbiosis/genética , Wolbachia/patogenicidad
19.
Cell Host Microbe ; 27(3): 329-344, 2020 Mar 11.
Artículo en Inglés | MEDLINE | ID: mdl-32164844

RESUMEN

The intestine is an essential physical and immunological barrier comprised of a monolayer of diverse and specialized epithelial cells that perform functions ranging from nutrient absorption to pathogen sensing and intestinal homeostasis. The intestinal barrier prevents translocation of intestinal microbes into internal compartments. The microbiota is comprised of a complex community largely populated by diverse bacterial species that provide metabolites, nutrients, and immune stimuli that promote intestinal and organismal health. Although commensal organisms promote health, enteric pathogens, including a diverse plethora of enteric viruses, cause acute and chronic diseases. The barrier epithelium plays fundamental roles in immune defenses against enteric viral infections by integrating diverse signals, including those from the microbiota, to prevent disease. Importantly, many model systems have contributed to our understanding of this complex interface. This review will focus on the antiviral mechanisms at play within the intestinal epithelium and how these responses are shaped by the microbiota.


Asunto(s)
Microbioma Gastrointestinal , Enfermedades Intestinales/virología , Mucosa Intestinal/microbiología , Virosis/patología , Animales , Caenorhabditis elegans/microbiología , Caenorhabditis elegans/virología , Culicidae/inmunología , Culicidae/virología , Drosophila melanogaster/inmunología , Drosophila melanogaster/virología , Humanos , Inmunidad Innata , Ratones , Virosis/microbiología
20.
PLoS Negl Trop Dis ; 14(3): e0008166, 2020 03.
Artículo en Inglés | MEDLINE | ID: mdl-32203536

RESUMEN

Flaviviruses such as yellow fever, dengue or Zika viruses are responsible for significant human and veterinary diseases worldwide. These viruses contain an RNA genome, prone to mutations, which enhances their potential to emerge as pathogens. Bamaga virus (BgV) is a mosquito-borne flavivirus in the yellow fever virus group that we have previously shown to be host-restricted in vertebrates and horizontally transmissible by Culex mosquitoes. Here, we aimed to characterise BgV host-restriction and to investigate the mechanisms involved. We showed that BgV could not replicate in a wide range of vertebrate cell lines and animal species. We determined that the mechanisms involved in BgV host-restriction were independent of the type-1 interferon response and RNAse L activity. Using a BgV infectious clone and two chimeric viruses generated as hybrids between BgV and West Nile virus, we demonstrated that BgV host-restriction occurred post-cell entry. Notably, BgV host-restriction was shown to be temperature-dependent, as BgV replicated in all vertebrate cell lines at 34°C but only in a subset at 37°C. Serial passaging of BgV in Vero cells resulted in adaptive mutants capable of efficient replication at 37°C. The identified mutations resulted in amino acid substitutions in NS4A-S124F, NS4B-N244K and NS5-G2C, all occurring close to a viral protease cleavage site (NS4A/2K and NS4B/NS5). These mutations were reverse engineered into infectious clones of BgV, which revealed that NS4B-N244K and NS5-G2C were sufficient to restore BgV replication in vertebrate cells at 37°C, while NS4A-S124F further increased replication efficiency. When these mutant viruses were injected into immunocompetent mice, alongside BgV and West Nile virus chimeras, infection and neurovirulence were enhanced as determined by clinical scores, seroconversion, micro-neutralisation, viremia, histopathology and immunohistochemistry, confirming the involvement of these residues in the attenuation of BgV. Our studies identify a new mechanism of host-restriction and attenuation of a mosquito-borne flavivirus.


Asunto(s)
Infecciones por Flavivirus/virología , Flavivirus/genética , Flavivirus/patogenicidad , Mutación , Proteínas no Estructurales Virales/genética , Animales , Encéfalo/patología , Encéfalo/virología , Línea Celular , Chlorocebus aethiops , Culicidae/virología , Modelos Animales de Enfermedad , Endorribonucleasas/metabolismo , Femenino , Flavivirus/fisiología , Infecciones por Flavivirus/metabolismo , Infecciones por Flavivirus/patología , Células HEK293 , Humanos , Masculino , Ratones , Mosquitos Vectores/virología , Células Vero , Virulencia/genética , Replicación Viral , Virus del Nilo Occidental/genética
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