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1.
Sci Rep ; 11(1): 6081, 2021 Mar 16.
Article in English | MEDLINE | ID: mdl-33727688

ABSTRACT

Although there are many studies on the control of mosquito vectors of the yellow fever virus (YFV) in tropical forests, there are still few ecological studies regarding abiotic factors effect on these mosquitoes. Here we characterize these effects on oviposition behavior, abundance, and diversity of mosquito vectors of YFV. The study was conducted in Córrego da Luz Municipal Park, in Casimiro de Abreu, Rio de Janeiro state, Brazil, from July 2018 to December 2019. Ovitraps were placed at ground level and 3 m high. The data were tested for normality using the Shapiro-Wilk test, followed by an independent sample analysis, the Mann-Whitney test. The Shannon Diversity Index was used to evaluate the abundance of mosquitos' eggs collected at both ground level and 3 m high. We highlight the presence of Haemagogus janthinomys and Hg. leucocelaenus, primary YFV vectors in forest areas. The abundance of Hg. leucocelaenus (63%), Hg. janthinomys (75%), and Aedes terrens (58%) was higher at the height of 3 m, while Ae. albopictus (52%) was higher at ground level. Aedes albopictus was positively correlated with temperature. Culicidae monitoring is essential for assessing the YFV transmission cycle in Atlantic forest fragments.

2.
Pest Manag Sci ; 2021 Feb 09.
Article in English | MEDLINE | ID: mdl-33559956

ABSTRACT

BACKGROUND: Aedes aegypti is a remarkably effective mosquito vector of epidemiologically important arboviral diseases including dengue fever, yellow fever and Zika. The present spread of resistance against pyrethroids, the primary insecticides used for mosquito control, in global populations of this species is of great concern. The voltage-gated sodium channel (VGSC) in the nervous system is the known target site of pyrethroids in insects. Past studies have revealed several amino-acid substitutions in this channel that confer pyrethroid resistance, which are known as knockdown resistance (kdr) mutations. RESULTS: This study investigated a laboratory colony of Ae. aegypti, MCNaeg, established from larvae collected in Rio de Janeiro, Brazil in 2016. The MCNaeg colony showed strong resistance against pyrethroids without laboratory selection. Of the two VGSC gene haplotypes present within this colony, one harbored three known kdr mutations, V410L, V1016I, and F1534C, and the other harbored only the known F1534C mutation. In latter haplotype, we also found novel amino-acid substations including V253F. Previous molecular modeling and electrophysiological studies suggest that this residue serves a pyrethroid-sensing site in the second receptor, PyR2. Our genetical analysis showed that the haplotype harboring V253F and F1534C is associated with equal or slightly stronger resistance than the other triple kdr haplotype to both Type I and Type II pyrethroids. CONCLUSION: The novel substitution V253F is potentially involved in pyrethroid resistance in Ae. aegypti. Further studies are needed to elucidate the role of this substitution in the pyrethroid susceptibility of VGSC.

3.
Article in English | MEDLINE | ID: mdl-33572650

ABSTRACT

Aedes aegypti is a cosmopolitan vector for arboviruses dengue, Zika and chikungunya, disseminated in all Brazilian states. The Eco-Bio-Social (EBS) strategy is vital in Aedes aegypti control as it mobilizes stakeholders (government, professionals, society, and academics) to promote healthy environments. This paper describes the rationale and methods of expanding the EBS strategy for Aedes aegypti control in Fortaleza, Northeast Brazil. A cluster, non-randomized controlled clinical trial was developed to analyze the strategy's effectiveness in vulnerable territories (high incidence of dengue and violent deaths; low HDI; substandard urban infrastructure, high population density, and water scarcity). We selected two intervention and two control groups, resulting in a sample of approximately 16,000 properties. The intervention consisted of environmental management by sealing large elevated water tanks, introduction of beta fish in waterholes, elimination of potential breeding sites, and mobilization and training of schoolchildren, endemic disease workers, health workers, social mobilizers, and community leaders; community surveillance of arboviruses; construction and validation of a booklet for the prevention of arboviruses in pregnant women. We analyzed the costs of arboviruses to government and households, the intervention cost-effectiveness, chikungunya's chronicity, and acceptance, sustainability, and governance of vector control actions. The primary outcome (infestation) was analyzed using the house, container, and Breteau indices. We hope that this study will help us understand how to scale up strategies to fight Aedes aegypti in vulnerable areas.


Subject(s)
Aedes , Dengue , Zika Virus Infection , Zika Virus , Animals , Brazil/epidemiology , Child , Dengue/epidemiology , Dengue/prevention & control , Female , Humans , Mosquito Control , Mosquito Vectors , Pregnancy , Zika Virus Infection/epidemiology , Zika Virus Infection/prevention & control
4.
Nursing (Säo Paulo) ; 24(273): 5229-5242, fev.2021.
Article in Portuguese | LILACS, BDENF - Nursing | ID: biblio-1148490

ABSTRACT

Objetivo: descrever incidência de dengue em Santos/SP e relacionar coeficiente de incidência (CI) de dengue com indicadores socioeconômicos e entomológicos de 2012-2016. Método: estudo epidemiológico, descritivo, ecológico dos casos confirmados de dengue, residentes em Santos, de 2012-2016, do Sistema de Informação de Agravos de Notificação-Online; foram obtidos seis indicadores socioeconômicos da base de setores censitários do Instituto Brasileiro de Geografia e Estatística-2010; o sétimo do Índice Paulista de Vulnerabilidade Social-2010 e os indicadores entomológicos da Secretaria de Saúde; foi aplicada Correlação bivariada de Spearman (SPSS-Statistics®). Aprovado pelo Comitê de Ética em Pesquisa-CAAE nº79776017.1.0000.5479. Resultados: de 2012-2016 ocorreram 16.451 casos, com CI de 117,4 (2012) a 2.122,8 (2013) casos/100.000 habitantes, maior no sexo feminino e de 15-29 anos; os fatores socioeconômicos foram mais significativos entre 2015-2016; o Índice de Densidade de fêmeas Aedes aegypti apresentou maior correlação positiva. Conclusão: descreveu-se perfil epidemiológico/entomológico da dengue, apoiando gestores nas ações locais de controle.(AU)


Objectives: describe incidence of dengue in Santos/SP and relate dengue incidence coefficient (IC) with socioeconomic and entomological indicators from 2012-2016. Methods: epidemiological, descriptive, ecological study of confirmed cases of dengue, resident in Santos, from 2012-2016, of the Online-Notifiable Diseases Information System; six socioeconomic indicators were obtained from census sectors base of Brazilian Institute of Geography and Statistics-2010; the seventh from the São Paulo Index of Social Vulnerability-2010 and the entomological indicators from the Health Department; Spearman's Bivariate Correlation (SPSS-Statistics®) was applied. Approved by the Research Ethics Committee-CAAE nº79776017.1.0000.5479. Results: from 2012-2016 there were 16.451 cases, with IC from 117,4 (2012) to 2.122,8 (2013) cases/100.000 inhabitants, higher in females and between 15-29 years old; socioeconomic factors were more significant between 2015-2016; the Density Index of Aedes aegypti females showed a greater positive correlation. Conclusion: epidemiological/entomological profile of dengue was described, supporting managers in local control actions.(AU)


Objetivos: describir incidencia del dengue en Santos/SP y relacionar coeficiente de incidencia (CI) del dengue con indicadores socioeconómicos y entomológicos para 2012-2016. Métodos: estudio epidemiológico, descriptivo, ecológico de casos confirmados de dengue, residentes en Santos, desde 2012-2016, del Sistema de Información de Enfermedades de Notificación-Online; obtuvieron-se seis indicadores socioeconómicos desde base de sectores censales del Instituto Brasileño de Geografía y Estadística-2010, el séptimo del Índice de Vulnerabilidad Social de São Paulo-2010 y los indicadores entomológicos del Departamento de Salud. Aplicó-se Correlación Bivariada de Spearman (SPSS-Statistics®). Aprobado por el Comité de Ética en Investigación-CAAE nº79776017.1.0000.5479. Resultados: desde 2012-2016 hubo 16.451 casos, con CI de 117,4 (2012) a 2.122,8 (2013) casos/100.000 habitantes, mayor en mujeres y de 15-29 años; los factores socioeconómicos fueron más significativos entre 2015-2016; el Índice de Densidad de hembras Aedes aegypti mostró mayor correlación positiva. Conclusión: describió-se perfil epidemiológico/entomológico del dengue, apoyando a los gerentes en acciones de control local.(AU)


Subject(s)
Humans , Public Health Nursing , Health Profile , Incidence , Aedes/virology , Dengue/epidemiology , Social Vulnerability Index , Socioeconomic Factors , Disaster Vulnerability/statistics & numerical data , Entomology
5.
Planta Med ; 87(1-02): 6-23, 2021 Feb.
Article in English | MEDLINE | ID: mdl-33348409

ABSTRACT

Natural products are a valuable source of biologically active compounds and continue to play an important role in modern drug discovery due to their great structural diversity and unique biological properties. Brazilian biodiversity is one of the most extensive in the world and could be an effective source of new chemical entities for drug discovery. Mosquitoes are vectors for the transmission of dengue, Zika, chikungunya, yellow fever, and many other diseases of public health importance. These diseases have a major impact on tropical and subtropical countries, and their incidence has increased dramatically in recent decades, reaching billions of people at risk worldwide. The prevention of these diseases is mainly through vector control, which is becoming more difficult because of the emergence of resistant mosquito populations to the chemical insecticides. Strategies to provide efficient and safe vector control are needed, and secondary metabolites from plant species from the Brazilian biodiversity, especially Cerrado, that are biologically active for mosquito control are herein highlighted. Also, this is a literature revision of targets as insights to promote advances in the task of developing active compounds for vector control. In view of the expansion and occurrence of arboviruses diseases worldwide, scientific reviews on bioactive natural products are important to provide molecular models for vector control and contribute with effective measures to reduce their incidence.


Subject(s)
Aedes , Zika Virus Infection , Zika Virus , Animals , Brazil , Models, Molecular , Mosquito Control , Mosquito Vectors
6.
Rev Soc Bras Med Trop ; 53: e20200467, 2020.
Article in English | MEDLINE | ID: mdl-33331611

ABSTRACT

INTRODUCTION: Semi-synthetic dillapiole compounds derived from Piper aduncum essential oil are used as alternative insecticides to control insecticide-resistant Aedes aegypti. Thus, we aimed to evaluate the genotoxic effects of semi-synthetic isodillapiole on the nuclei of neuroblasts (larvae) and oocytes (females) and the mean oviposition rates of the females over four generations (G1, G2, G3, and G4) of Ae. aegypti. METHODS: Larvae were captured in the city of Manaus, Amazonas state, Brazil, and exposed to isodillapiole in bioassays (20, 40, and 60 µg/mL) and a negative control (0.05% DMSO in tap water) for 4 h. The cerebral ganglia were extracted from the larvae and oocytes from the adult females to prepare slides for cytogenetic analysis. Breeding pairs were established and eggs counts were quantified taken after the bioassays. RESULTS: The analysis of 20,000 interphase nuclei of neuroblasts and oocytes indicated significant genotoxicity (micronuclei, budding, polynucleated cells, and other malformations) compared to that of the control. Metaphasic and anaphasic nuclei presented chromosomal breaks; however, no significant variation and damage was observed in the negative control. A significant reduction in mean oviposition rates was also recorded following exposure to isodillapiole over the four generations (G1, G2, G3, and G4). CONCLUSIONS: The toxic and genotoxic effects of isodillapiole on Ae. aegypti were caused by reduced oviposition in the females and nuclear abnormalities over the four generations of the trials. Further studies are required, rather than our in vitro assays, to verify the efficacy of exposure to this compound for controlling Ae. aegypti.


Subject(s)
Aedes , Insecticides , Animals , Brazil , DNA Damage , Female , Insecticides/toxicity , Larva , Oviposition
7.
Internet resource in Portuguese | LIS -Health Information Locator | ID: lis-47980

ABSTRACT

Para mobilizar a população e os gestores locais contra a proliferação de focos do Aedes aegypti, o Ministério da Saúde lançou, nesta terça-feira (24), campanha de combate ao mosquito. Com o conceito “Combater o mosquito é com você, comigo, com todo mundo”, a campanha busca conscientizar sobre os perigos do inseto e motivar os brasileiros para o combate aos criadouros


Subject(s)
Aedes , Health Promotion
8.
Infect Genet Evol ; 86: 104626, 2020 Dec.
Article in English | MEDLINE | ID: mdl-33166684

ABSTRACT

Human actions intensify the greenhouse effect, aggravating climate changes in the Amazon and elsewhere in the world. The Intergovernmental Panel on Climate Change (IPCC) foresees a global increase of up to 4.5 °C and 850 ppm CO2 (above current levels) by 2100. This will impact the biology of the Aedes aegypti mosquito, vector of Dengue, Zika, urban Yellow Fever and Chikungunya. Heat shock proteins are associated with adaptations to anthropic environments and the interaction of some viruses with the vector. The transcription of the hsp26, hsp83 and hsc70 genes of an A. aegypti population, maintained for more than forty-eight generations, in the Current, Intermediate and Extreme climatic scenario predicted by the IPCC was evaluated with qPCR. In females, highest levels of hsp26, hsp83 and hsc70 expression occurred in the Intermediate scenario, while in males, levels were high only for hsp26 gene in Current and Extreme scenarios. Expression of hsp83 and hsc70 genes in males was low under all climatic scenarios, while in the Extreme scenario females had lower expression than in the Current scenario. The data suggest compensatory or adaptive processes acting on heat shock proteins, which can lead to changes in the mosquito's biology, altering vectorial competence.

9.
Mem Inst Oswaldo Cruz ; 115: e200271, 2020.
Article in English | MEDLINE | ID: mdl-33146241

ABSTRACT

BACKGROUND: Aedes aegypti is the primary transmitter of several arbovirus with great impact in human health. Controlling vector mosquitoes is an essential and complex task. One promising control method is to use mosquitoes as a vehicle to disseminate tiny particles of juvenile-killing insecticides, such as pyriproxyfen (PPF), to breeding sites. OBJECTIVES: We aimed to investigate the capacity of Ae. aegypti to disseminate two new formulations of PPF in two sites of Rio de Janeiro city for assessment of the efficacy of these products. METHODS: Dissemination stations impregnated with powder and liquid new formulations of PPF were installed in two test sites. Ovitraps were used in the test sites and in a control site for monitoring the presence of Ae. aegypti throughout eggs collection. FINDINGS: Entomological indices indicated that the new formulations of PPF were efficient in reducing eggs abundance. Liquid formulation performed better than powder formulation. Ready-to-use formulations of PPF can be quickly applied in the field and can be replaced after a few months. MAIN CONCLUSIONS: New formulations of PPF associated with mosquito dissemination approach make a valuable vector control strategy, managing to cover places of difficult access for whatever reason. New formulations application requires less labour, being economically attractive.


Subject(s)
Aedes/drug effects , Insecticides/pharmacology , Larva/drug effects , Mosquito Control/methods , Pyridines/pharmacology , Adolescent , Animals , Cities , Humans , Larva/growth & development , Mosquito Vectors/drug effects , Mosquito Vectors/growth & development
10.
Sci Robot ; 5(43)2020 Jun 15.
Article in English | MEDLINE | ID: mdl-33022616

ABSTRACT

Genetic control methods of mosquito vectors of malaria, dengue, yellow fever, and Zika are becoming increasingly popular due to the limitations of other techniques such as the use of insecticides. The sterile insect technique is an effective genetic control method to manage insect populations. However, it is crucial to release sterile mosquitoes by air to ensure homogeneous coverage, especially in large areas. Here, we report a fully automated adult mosquito release system operated from an uncrewed aerial vehicle or drone. Our system, developed and tested in Brazil, enabled a homogeneous dispersal of sterile male Aedes aegypti while maintaining their quality, leading to a homogeneous sterile-to-wild male ratio due to their aggregation in the same sites. Our results indicate that the released sterile males were able to compete with the wild males in mating with the wild females; thus, the sterile males were able to induce sterility in the native female population. The use of drones to implement the sterile insect technique will lead to improvements in areal coverage and savings in operational costs due to the requirement of fewer release sites and field staff.

11.
PLoS Negl Trop Dis ; 14(10): e0008658, 2020 10.
Article in English | MEDLINE | ID: mdl-33017419

ABSTRACT

BACKGROUND: From the end of 2016 until the beginning of 2019, Brazil faced a massive sylvatic yellow fever (YF) outbreak. The 2016-2019 YF epidemics affected densely populated areas, especially the Southeast region, causing thousands of deaths of humans and non-human primates (NHP). METHODOLOGY/PRINCIPAL FINDINGS: We conducted a molecular investigation of yellow fever virus (YFV) RNA in 781 NHP carcasses collected in the urban, urban-rural interface, and rural areas of Minas Gerais state, from January 2017 to December 2018. Samples were analyzed according to the period of sampling, NHP genera, sampling areas, and sampling areas/NHP genera to compare the proportions of YFV-positive carcasses and the estimated YFV genomic loads. YFV infection was confirmed in 38.1% of NHP carcasses (including specimens of the genera Alouatta, Callicebus, Callithrix, and Sapajus), from the urban, urban-rural interface, and rural areas. YFV RNA detection was positively associated with epidemic periods (especially from December to March) and the rural environment. Higher median viral genomic loads (one million times) were estimated in carcasses collected in rural areas compared to urban ones. CONCLUSIONS/SIGNIFICANCE: The results showed the wide occurrence of YF in Minas Gerais in epidemic and non-epidemic periods. According to the sylvatic pattern of YF, a gradient of viral dissemination from rural towards urban areas was observed. A high YF positivity was observed for NHP carcasses collected in urban areas with a widespread occurrence in 67 municipalities of Minas Gerais, including large urban centers. Although there was no documented case of urban/Aedes YFV transmission to humans in Brazil during the 2016-2019 outbreaks, YFV-infected NHP in urban areas with high infestation by Aedes aegypti poses risks for YFV urban/Aedes transmission and urbanization.

12.
J Infect ; 81(5): 766-775, 2020 Nov.
Article in English | MEDLINE | ID: mdl-32987099

ABSTRACT

OBJECTIVES: Screening for genes differentially expressed in placental tissues, aiming to identify transcriptional signatures that may be involved in ZIKV congenital pathogenesis. METHODS: Transcriptome data from placental tissues of pregnant women naturally infected with Zika virus during the third trimester were compared to those from women who tested negative for Zika infection. The findings were validated using both a cell culture model and an immunohistochemistry/morphological analysis of naturally infected placental tissues. RESULTS: Transcriptome analysis revealed that Zika virus infection induces downregulation of insulin-like growth factor II (IGF2) gene, an essential factor for fetal development. The Caco-2 cell culture model that constitutively expresses IGF2 was used for the transcriptome validation. Asiatic and African Zika virus strains infection caused downregulated IGF2 gene expression in Caco-2 cells, whereas other flaviviruses, such as dengue serotype 1, West Nile and wild-type yellow fever viruses, had no effect on this gene expression. Immunohistochemical assays on decidual tissues corroborated our transcriptome analysis, showing that IGF2 is reduced in the decidua of Zika virus-infected women. CONCLUSIONS: Our results draw attention to IGF2 modulation in uterine tissues, and this finding is expected to support future studies on strategies to ameliorate the harmful effects of Zika virus infection during pregnancy.

13.
Acta Trop ; 212: 105705, 2020 Sep 19.
Article in English | MEDLINE | ID: mdl-32956639

ABSTRACT

This review focused on the toxicity of essential oils and their constituents against Aedes aegypti L. (Diptera, Culicidae) larvae, a key vector of important arboviral diseases, such as dengue, chikungunya, zika, and yellow fever. This review is based on original articles obtained by searching major databases in the last six years. Our literature review shows that 337 essential oils from 225 plant species have been tested for larvicidal bioactivity. More than 60% of these essential oils were considered active (LC50<100 µg/mL). Most species belong to the families Lamiaceae (19.3%), Lauraceae (9.9%), and Myrtaceae (9.4%). The plants studied for their larvicidal activity against A. aegypti were mainly collected in India and Brazil (30 and 20%, respectively) and the parts of the plants most used were the leaves. Less than 10% of essential oils were evaluated for toxicity against non-target organisms and with the aim to demonstrate safe use. The most used plant parts are leaves and the main compounds of essential oils were described. The most active essential oils are rich in sesquiterpene hydrocarbons, oxygenated sesquiterpenes, and monoterpene hydrocarbons. Here, factors affecting bioactivity (chemical composition, plant parts, and harvesting site) of essential oils and their constituents, as well as safety to non-target organisms are discussed. Essential oils have considerable potential against A. aegypti. This review shows that essential oils might be used to control arboviruses, and further studies on safety and formulations for application in the field should be performed.

14.
Rev Panam Salud Publica ; 44: e116, 2020.
Article in English | MEDLINE | ID: mdl-32952536

ABSTRACT

Objective: To establish the risk of microcephaly in neonates born to women infected with ZIKV during pregnancy. Methods: A cohort of laboratory-confirmed ZIKV cases of congenital infections (109 mothers infected during pregnancy and 101 newborns) among 308 suspect cases was followed in Belem, Pará, Brazil, from October 2015 to December 2017. Results: A microcephaly risk of 1.98% (95% CI 0.54-6.93%) was found, or 2 cases among the 101 neonates infected with ZIKV during pregnancy. 72% of the pregnant women had ZIKV infection confirmed by RT-qPCR during gestation. Conclusions: Results showed a low incidence of ZIKV-associated birth defects, stillbirth, and miscarriage, which contrasts with previous studies in other Brazilian regions. Previous exposure to yellow fever vaccine and/or multiserotype DENV infection could be implicated in the protection from ZIKV congenital infection.

15.
J Virol Methods ; 286: 113976, 2020 Dec.
Article in English | MEDLINE | ID: mdl-32971183

ABSTRACT

Zika and Dengue viruses present considerable immunological cross-reactivity, resulting in a troublesome serodiagnosis due to occurrence of false positive results. Due to Brazil's wide variety of circulating flaviviruses we aimed to access the use of in house serological tests adapted by National Reference Laboratory for Arboviruses in Brazil and evaluate commercial tests available. We evaluated in house IgM ELISAs for the individual detection of anti-ZIKV, -DENV, and -YFV IgM, against a panel of samples positive for dengue, zika, yellow fever, Rocio, Ilheus, Saint Louis encephalitis, West Nile and chikungunya. We also evaluated two commercial kits for dengue and zika IgM detection recommended by the Brazilian Ministry of Health in 2015. The sensitivity and specificity for the in house ZIKV IgM ELISA was 60.0 % and 88.6 % and for the in house DENV IgM ELISA was 100 % and 82.2 %, respectively. The in house YFV IgM ELISA presented 100 % for both sensitivity and specificity. The Novagnost Zika Virus IgM test presented a sensitivity of 47.3 % and specificity of 85.3 % and the Serion ELISA classic Dengue Virus IgM, 92.8 % and 58.9 %, respectively. Overall, both in house ELISAs for ZIKV and DENV adapted and evaluated here, presented better performances than the commercial kits tested.

16.
Rev Soc Bras Med Trop ; 53: e20200176, 2020.
Article in English | MEDLINE | ID: mdl-32935784

ABSTRACT

INTRODUCTION: Curtailing the development of the aquatic immature stages of Aedes aegypti is one of the main measures to limit their spread and the diseases transmitted by them. The use of plant extracts is a promising approach in the development of natural insecticides. Thus, this research aimed to characterize the inhibitory effect of the hydroalcoholic extract of Caryocar brasiliense leaves on the emergence of adult A. aegypti and the main substances that constitute this extract. METHODS: C. brasiliense leaf extract was prepared by ethanol (70%) extraction. Bioassays using L3 larvae were performed at concentrations of 200, 300, 400, and 500 ppm. We identified the major secondary metabolites present in this extract, and performed toxicity tests on an off-target organism, Danio rerio. RESULTS: We observed a significant delay in the development of A. aegypti larvae mainly at a concentration of 500 ppm, and estimated an emergence inhibition for 50% of the population of 150 ppm. Moreover, the C. brasiliense leaf extracts exhibited low toxicity in D. rerio. The main compounds found in the extract were quercetin, violaxanthin, myricetin3-O-hexoside, methyl-elagic-3-arabinose acid, and isoquercitrin. CONCLUSIONS: Herein, we demonstrate the inhibition of mosquito development by the hydroalcoholic extract of C. brasiliense and suggest substances that may act as active principles.


Subject(s)
Aedes , Animals , Insecticides , Larva , Plant Extracts , Plant Leaves
17.
PLoS Negl Trop Dis ; 14(9): e0008527, 2020 09.
Article in English | MEDLINE | ID: mdl-32898136

ABSTRACT

BACKGROUND: Zika virus (ZIKV) emerged in the Pacific Ocean and subsequently caused a dramatic Pan-American epidemic after its first appearance in the Northeast region of Brazil in 2015. The virus is transmitted by Aedes mosquitoes. We evaluated the role of temperature and infectious doses of ZIKV in vector competence of Brazilian populations of Ae. aegypti and Ae. albopictus. METHODOLOGY/PRINCIPAL FINDINGS: Two Ae. aegypti (Rio de Janeiro and Natal) and two Ae. albopictus (Rio de Janeiro and Manaus) populations were orally challenged with five viral doses (102 to 106 PFU / ml) of a ZIKV strain (Asian genotype) isolated in Northeastern Brazil, and incubated for 14 and 21 days in temperatures mimicking the spring-summer (28°C) and winter-autumn (22°C) mean values in Brazil. Detection of viral particles in the body, head and saliva samples was done by plaque assays in cell culture for determining the infection, dissemination and transmission rates, respectively. Compared with 28°C, at 22°C, transmission rates were significantly lower for both Ae. aegypti populations, and Ae. albopictus were not able to transmit the virus. Ae. albopictus showed low transmission rates even when challenged with the highest viral dose, while both Ae. aegypti populations presented higher of infection, dissemination and transmission rates than Ae. albopictus. Ae. aegypti showed higher transmission efficiency when taking virus doses of 105 and 106 PFU/mL following incubation at 28°C; both Ae. aegypti and Ae. albopictus were unable to transmit ZIKV with virus doses of 102 and 103 PFU/mL, regardless the incubation temperature. CONCLUSIONS/SIGNIFICANCE: The ingested viral dose and incubation temperature were significant predictors of the proportion of mosquito's biting becoming infectious. Ae. aegypti and Ae. albopictus have the ability to transmit ZIKV when incubated at 28°C. However Brazilian populations of Ae. aegypti exhibit a much higher transmission potential for ZIKV than Ae. albopictus regardless the combination of infection dose and incubation temperature.


Subject(s)
Aedes/virology , Saliva/virology , Zika Virus Infection/transmission , Animals , Brazil , Insect Bites and Stings/virology , Mosquito Vectors/virology , Seasons , Temperature , Tissue Distribution , Viral Load , Zika Virus
18.
Parasit Vectors ; 13(1): 479, 2020 Sep 18.
Article in English | MEDLINE | ID: mdl-32948231

ABSTRACT

BACKGROUND: Since the huge epidemic of Zika virus (ZIKV) in Brazil in 2015, questions were raised to understand which mosquito species could transmit the virus. Aedes aegypti has been described as the main vector. However, other Aedes species (e.g. Ae. albopictus and Ae. japonicus) proven to be competent for other flaviviruses (e.g. West Nile, dengue and yellow fever), have been described as potential vectors for ZIKV under laboratory conditions. One of these, the Asian bush mosquito, Ae. japonicus, is widely distributed with high abundances in central-western Europe. In the present study, infection, dissemination and transmission rates of ZIKV (Dak84 strain) in two populations of Ae. japonicus from Switzerland (Zürich) and France (Steinbach, Haut-Rhin) were investigated under constant (27 °C) and fluctuating (14-27 °C, mean 23 °C) temperature regimes. RESULTS: The two populations were each able to transmit ZIKV under both temperature regimes. Infectious virus particles were detected in the saliva of females from both populations, regardless of the incubation temperature regime, from 7 days post-exposure to infectious rabbit blood. The highest amount of plaque forming units (PFU) (400/ml) were recorded 14 days post-oral infection in the Swiss population incubated at a constant temperature. No difference in terms of infection, dissemination and transmission rate were found between mosquito populations. Temperature had no effect on infection rate but the fluctuating temperature regime resulted in higher dissemination rates compared to constant temperature, regardless of the population. Finally, transmission efficiency ranged between 7-23% and 7-10% for the constant temperature and 0-10% and 3-27% under fluctuating temperatures for the Swiss and the French populations, respectively. CONCLUSIONS: To the best of our knowledge, this is the first study confirming vector competence for ZIKV of Ae. japonicus originating from Switzerland and France at realistic summer temperatures under laboratory conditions. Considering the continuous spread of this species in the northern part of Europe and its adaptation at cooler temperatures, preventative control measures should be adopted to prevent possible ZIKV epidemics.

19.
Rev Panam Salud Publica ; 44, sept. 2020
Article in English | PAHO-IRIS | ID: phr-52652

ABSTRACT

Objective. To establish the risk of microcephaly in neonates born to women infected with ZIKV during pregnancy. Methods. A cohort of laboratory-confirmed ZIKV cases of congenital infections (109 mothers infected during pregnancy and 101 newborns) among 308 suspect cases was followed in Belem, Pará, Brazil, from October 2015 to December 2017. Results. A microcephaly risk of 1.98% (95% CI 0.54-6.93%) was found, or 2 cases among the 101 neonates infected with ZIKV during pregnancy. 72% of the pregnant women had ZIKV infection confirmed by RT-qPCR during gestation. Conclusions. Results showed a low incidence of ZIKV-associated birth defects, stillbirth, and miscarriage, which contrasts with previous studies in other Brazilian regions. Previous exposure to yellow fever vaccine and/ or multiserotype DENV infection could be implicated in the protection from ZIKV congenital infection.


Objetivo. Establecer el riesgo de microcefalia en los recién nacidos de mujeres infectadas con ZIKV durante el embarazo. Métodos. Se siguió a una cohorte de casos con infección congénita por ZIKV confirmada por laboratorio (109 madres infectadas durante el embarazo, 101 recién nacidos) conformada a partir de 308 casos sospechosos en Belem, Pará, Brasil, de octubre de 2015 a diciembre de 2017. Resultados. Se encontró un riesgo de microcefalia de 1,98% (IC95% 0,54-6,93%), o 2 casos entre los 101 neonatos infectados con ZIKV durante el embarazo. En el 72% de las mujeres embarazadas se confirmó mediante RT-qPCR la infección por ZIKV durante la gestación. Conclusiones. Los resultados mostraron una baja incidencia de malformaciones congénitas, mortinatos y abortos asociados al ZIKV, lo que contrasta con estudios anteriores de otras regiones de Brasil. La exposición previa a la vacuna contra la fiebre amarilla o la infección previa por varios serotipos de virus del dengue podrían estar implicados en la protección contra la infección congénita por ZIKV.


Subject(s)
Zika Virus Infection , Pregnancy Complications , Microcephaly , Zika Virus Infection , Microcephaly , Pregnancy Complications, Infectious , Brazil
20.
J Biomol Struct Dyn ; : 1-13, 2020 Aug 20.
Article in English | MEDLINE | ID: mdl-32815781

ABSTRACT

Arboviruses are a group of viruses (e.g. Dengue, Chikungunya and Yellow fever virus) that are transmitted by arthropod vectors, which Aedes aegipty is the vector of main viruses in Americas. This vector is responsible to 2.4 millions of arboviruses cases in Brazil with less than a thousand deaths annually. Despite of epidemiological data, arboviruses treatment is symptomatic and the vaccine control is not effective, which makes the vector control against A. aegipty a promising strategy to diseases control. One way to achieve this goal is to development of A. aegipty sensitive olfactory modulators. Odorant binding protein 1 from A. aegypti (AaegOBP1) is essential in sensory communication, and is the first filter in odorant selection, which makes this target promising to development of new repellents. For this reason, hierarchical virtual screening (ligand-based pharmacophore model and molecular docking) together volatility filter was applied at Sigma-Aldrich database (n = 126.851) to prioritize potential molecules to repellency assays. Three compounds showed adequate stereo-electronic requirements (QFIT> 81.53), score to AaegOBP1 binding site (Score > 36.0) and volatile properties and it was chosen for repellency assays. ZINC00170981 and ZINC00131924 showed a dose-response behavior, while ZINC01621824 did not showed activity in repellency assays. Finally, Molecular Dynamics (MD) was employed to hypothesize the stability of protein-ligand complexes. According to RMSD, RMSF and binding free energy data, ZINC00170981 and ZINC00131924 were able to stabilize AaegOBP1 binding-site during the trajectory by interactions with key residues such as His77, Leu89 and Trp114). Communicated by Ramaswamy H. Sarma.

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