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1.
Nat Commun ; 12(1): 1671, 2021 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-33723237

RESUMO

Zika virus (ZIKV) has caused large, brief outbreaks in isolated populations, however ZIKV can also persist at low levels over multiple years. The reasons for these diverse transmission dynamics remain poorly understood. In Fiji, which has experienced multiple large single-season dengue epidemics, there was evidence of multi-year transmission of ZIKV between 2013 and 2017. To identify factors that could explain these differences in dynamics between closely related mosquito-borne flaviviruses, we jointly fit a transmission dynamic model to surveillance, serological and molecular data. We estimate that the observed dynamics of ZIKV were the result of two key factors: strong seasonal effects, which created an ecologically optimal time of year for outbreaks; and introduction of ZIKV after this optimal time, which allowed ZIKV transmission to persist over multiple seasons. The ability to jointly fit to multiple data sources could help identify a similar range of possible outbreak dynamics in other settings.


Assuntos
Infecções por Flavivirus/epidemiologia , Infecções por Flavivirus/transmissão , Animais , Culicidae , Dengue/transmissão , Vírus da Dengue , Surtos de Doenças , Epidemias , Fiji/epidemiologia , Flavivirus , Humanos , Mosquitos Vetores/virologia , Estações do Ano , Zika virus , Infecção por Zika virus/epidemiologia , Infecção por Zika virus/transmissão
2.
Nat Commun ; 12(1): 916, 2021 02 10.
Artigo em Inglês | MEDLINE | ID: mdl-33568638

RESUMO

The global emergence of Zika virus (ZIKV) revealed the unprecedented ability for a mosquito-borne virus to cause congenital birth defects. A puzzling aspect of ZIKV emergence is that all human outbreaks and birth defects to date have been exclusively associated with the Asian ZIKV lineage, despite a growing body of laboratory evidence pointing towards higher transmissibility and pathogenicity of the African ZIKV lineage. Whether this apparent paradox reflects the use of relatively old African ZIKV strains in most laboratory studies is unclear. Here, we experimentally compare seven low-passage ZIKV strains representing the recently circulating viral genetic diversity. We find that recent African ZIKV strains display higher transmissibility in mosquitoes and higher lethality in both adult and fetal mice than their Asian counterparts. We emphasize the high epidemic potential of African ZIKV strains and suggest that they could more easily go unnoticed by public health surveillance systems than Asian strains due to their propensity to cause fetal loss rather than birth defects.


Assuntos
Infecção por Zika virus/mortalidade , Infecção por Zika virus/virologia , Zika virus/fisiologia , Zika virus/patogenicidade , Aedes/fisiologia , Aedes/virologia , África , Animais , Ásia , Feminino , Humanos , Masculino , Camundongos , Filogenia , Virulência , Zika virus/classificação , Zika virus/genética , Infecção por Zika virus/transmissão
3.
Viruses ; 13(2)2021 02 04.
Artigo em Inglês | MEDLINE | ID: mdl-33557048

RESUMO

Recent outbreaks of Zika virus (ZIKV) infection highlight the urgent need to evaluate the efficacy of current public health measures to educate susceptible groups about how to prevent infection, modes of viral transmission, and consequences of infection. We performed a cross-sectional study in the city of Jundiaí, São-Paulo, from March 2016 to August 2017. In 315 high-risk pregnant women we evaluated the rate of ZIKV infection, knowledge of pathways of ZIKV transmission, and the use of protective measures. Data were analyzed and correlated with sociodemographic variables. The rate of ZIKV infection was 10.8%. ZIKV transmission by mosquitoes was the best-known means of virus acquisition, while transmission of ZIKV by sexual intercourse as well as mother-fetus transmission was known by less than half of the women. The use of insect repellent, reported by 53% of participants, was correlated with higher education and personal directives from health professionals. Condom use was reported by 19.5% of subjects. Improved strategies to increase awareness of ZIKV infection and its consequences, designed to appeal to specific, targeted populations, are clearly necessary to more accurately prevent the spread of this infection and diminish adverse consequences in the pregnant population.


Assuntos
Conhecimentos, Atitudes e Prática em Saúde , Complicações Infecciosas na Gravidez/prevenção & controle , Gestantes , Infecção por Zika virus/prevenção & controle , Infecção por Zika virus/transmissão , Adolescente , Adulto , Brasil/epidemiologia , Estudos Transversais , Feminino , Humanos , Pessoa de Meia-Idade , Gravidez , Complicações Infecciosas na Gravidez/epidemiologia , Risco , Adulto Jovem , Zika virus , Infecção por Zika virus/epidemiologia
4.
Nat Commun ; 12(1): 151, 2021 01 08.
Artigo em Inglês | MEDLINE | ID: mdl-33420058

RESUMO

Mosquito-borne viruses threaten the Caribbean due to the region's tropical climate and seasonal reception of international tourists. Outbreaks of chikungunya and Zika have demonstrated the rapidity with which these viruses can spread. Concurrently, dengue fever cases have climbed over the past decade. Sustainable disease control measures are urgently needed to quell virus transmission and prevent future outbreaks. Here, to improve upon current control methods, we analyze temporal and spatial patterns of chikungunya, Zika, and dengue outbreaks reported in the Dominican Republic between 2012 and 2018. The viruses that cause these outbreaks are transmitted by Aedes mosquitoes, which are sensitive to seasonal climatological variability. We evaluate whether climate and the spatio-temporal dynamics of dengue outbreaks could explain patterns of emerging disease outbreaks. We find that emerging disease outbreaks were robust to the climatological and spatio-temporal constraints defining seasonal dengue outbreak dynamics, indicating that constant surveillance is required to prevent future health crises.


Assuntos
Febre de Chikungunya/epidemiologia , Doenças Transmissíveis Emergentes/epidemiologia , Dengue/epidemiologia , Surtos de Doenças/estatística & dados numéricos , Doenças Endêmicas/estatística & dados numéricos , Infecção por Zika virus/epidemiologia , Adolescente , Aedes/virologia , Animais , Febre de Chikungunya/prevenção & controle , Febre de Chikungunya/transmissão , Febre de Chikungunya/virologia , Vírus Chikungunya/isolamento & purificação , Criança , Pré-Escolar , Doenças Transmissíveis Emergentes/prevenção & controle , Doenças Transmissíveis Emergentes/transmissão , Doenças Transmissíveis Emergentes/virologia , Dengue/prevenção & controle , Dengue/transmissão , Dengue/virologia , Vírus da Dengue/isolamento & purificação , Surtos de Doenças/prevenção & controle , República Dominicana/epidemiologia , Doenças Endêmicas/prevenção & controle , Monitoramento Epidemiológico , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Controle de Mosquitos , Mosquitos Vetores/virologia , Análise Espaço-Temporal , Adulto Jovem , Zika virus/isolamento & purificação , Infecção por Zika virus/prevenção & controle , Infecção por Zika virus/transmissão , Infecção por Zika virus/virologia
5.
Artigo em Inglês | MEDLINE | ID: mdl-33401753

RESUMO

Infectious diseases have caused some of the most feared plagues and greatly harmed human health. However, despite the qualitative understanding that the occurrence and diffusion of infectious disease is related to the environment, the quantitative relations are unknown for many diseases. Zika virus (ZIKV) is a mosquito-borne virus that poses a fatal threat and has spread explosively throughout the world, impacting human health. From a geographical perspective, this study aims to understand the global hotspots of ZIKV as well as the spatially heterogeneous relationship between ZIKV and environmental factors using exploratory special data analysis (ESDA) model. A geographically weighted regression (GWR) model was used to analyze the influence of the dominant environmental factors on the spread of ZIKV at the continental scale. The results indicated that ZIKV transmission had obvious regional and seasonal heterogeneity. Population density, GDP per capita, and landscape fragmentation were the dominant environmental factors affecting the spread of ZIKV, which indicates that social factors had a greater influence than natural factors on the spread of it. As SARS-CoV-2 is spreading globally, this study can provide methodological reference for fighting against the pandemic.


Assuntos
Infecção por Zika virus , Animais , Humanos , Mosquitos Vetores , Análise Espaço-Temporal , Zika virus , Infecção por Zika virus/epidemiologia , Infecção por Zika virus/transmissão
6.
Viruses ; 13(1)2021 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-33477428

RESUMO

We systematically searched regional and international databases and screened 1658 non-duplicate records describing women with suspected or confirmed ZIKV infection, intending to breastfeed or give breast milk to an infant to examine the potential of mother-to-child transmission of Zika virus (ZIKV) through breast milk or breastfeeding-related practices. Fourteen studies met our inclusion criteria and inform this analysis. These studies reported on 97 mother-children pairs who provided breast milk for ZIKV assessment. Seventeen breast milk samples from different women were found positive for ZIKV via RT-PCR, and ZIKV replication was found in cell cultures from five out of seven breast milk samples from different women. Only three out of six infants who had ZIKV infection were breastfed, no evidence of clinical complications was found to be associated with ZIKV RNA in breast milk. This review updates our previous report by including 12 new articles, in which we found no evidence of ZIKV mother-to-child transmission through breast milk intake or breastfeeding. As the certainty of the present evidence is low, additional studies are still warranted to determine if ZIKV can be transmitted through breastfeeding.


Assuntos
Aleitamento Materno , Transmissão Vertical de Doença Infecciosa , Leite Humano/virologia , Infecção por Zika virus/epidemiologia , Infecção por Zika virus/transmissão , Zika virus , Aleitamento Materno/efeitos adversos , Humanos , Avaliação de Resultados em Cuidados de Saúde , Vigilância em Saúde Pública , Ensaios Clínicos Controlados Aleatórios como Assunto , Infecção por Zika virus/virologia
7.
Nat Commun ; 12(1): 595, 2021 01 26.
Artigo em Inglês | MEDLINE | ID: mdl-33500409

RESUMO

Zika virus (ZIKV) emerged from obscurity in 2013 to spread from Asia to the South Pacific and the Americas, where millions of people were infected, accompanied by severe disease including microcephaly following congenital infections. Phylogenetic studies have shown that ZIKV evolved in Africa and later spread to Asia, and that the Asian lineage is responsible for the recent epidemics in the South Pacific and Americas. However, the reasons for the sudden emergence of ZIKV remain enigmatic. Here we report evolutionary analyses that revealed four mutations, which occurred just before ZIKV introduction to the Americas, represent direct reversions of previous mutations that accompanied earlier spread from Africa to Asia and early circulation there. Our experimental infections of Aedes aegypti mosquitoes, human cells, and mice using ZIKV strains with and without these mutations demonstrate that the original mutations reduced fitness for urban, human-amplifed transmission, while the reversions restored fitness, increasing epidemic risk. These findings include characterization of three transmission-adaptive ZIKV mutations, and demonstration that these and one identified previously restored fitness for epidemic transmission soon before introduction into the Americas. The initial mutations may have followed founder effects and/or drift when the virus was introduced decades ago into Asia.


Assuntos
Epidemias , Evolução Molecular , Aptidão Genética , Infecção por Zika virus/epidemiologia , Zika virus/genética , Aedes/virologia , África/epidemiologia , América/epidemiologia , Substituição de Aminoácidos , Animais , Ásia/epidemiologia , Linhagem Celular , Modelos Animais de Doenças , Feminino , Fibroblastos , Humanos , Queratinócitos , Camundongos , Mutação , Filogenia , Cultura Primária de Células , Saúde da População Urbana/estatística & dados numéricos , Zika virus/patogenicidade , Infecção por Zika virus/transmissão , Infecção por Zika virus/virologia
8.
PLoS One ; 15(12): e0242367, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33320867

RESUMO

BACKGROUND: The signs and symptoms of Zika virus infection are usually mild and self-limited. However, the disease has been linked to neurological complications such as Guillain-Barré syndrome and peripheral nerve involvement, and also to abortion and fetal deaths due to vertical transmission, resulting in various congenital malformations in newborns, including microcephaly. This review aimed to describe the o signs and symptoms that characterize the congenital Zika syndrome. METHODS AND FINDINGS: A systematic review was performed with a protocol and described according to the recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. The search strategy yielded 2,048 studies. After the exclusion of duplicates and application of inclusion criteria, 46 studies were included. The main signs and symptoms associated with the congenital Zika syndrome were microcephaly, parenchymal or cerebellar calcifications, ventriculomegaly, central nervous system hypoplasia or atrophy, arthrogryposis, ocular findings in the posterior and anterior segments, abnormal visual function and low birthweight for gestational age. CONCLUSIONS: Zika virus infection during pregnancy can cause a series of changes in the growth and development of children, while impacting the healthcare system due to the severity of cases. Our findings outline the disease profile in newborns and infants and may contribute to the development and updating of more specific clinical protocols.


Assuntos
Síndrome de Guillain-Barré/diagnóstico , Transmissão Vertical de Doença Infecciosa , Malformações do Sistema Nervoso/diagnóstico , Complicações Infecciosas na Gravidez/virologia , Infecção por Zika virus/transmissão , Desenvolvimento Infantil/fisiologia , Feminino , Síndrome de Guillain-Barré/virologia , Humanos , Lactente , Recém-Nascido , Malformações do Sistema Nervoso/fisiopatologia , Malformações do Sistema Nervoso/virologia , Gravidez , Síndrome , Zika virus/patogenicidade , Infecção por Zika virus/complicações , Infecção por Zika virus/congênito , Infecção por Zika virus/virologia
9.
PLoS Negl Trop Dis ; 14(12): e0008971, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33338046

RESUMO

Aedes aegypti is a vector of dengue, chikungunya, and Zika viruses. Current vector control strategies such as community engagement, source reduction, and insecticides have not been sufficient to prevent viral outbreaks. Thus, interest in novel strategies involving genetic engineering is growing. Female mosquitoes rely on flight to mate with males and obtain a bloodmeal from a host. We hypothesized that knockout of genes specifically expressed in female mosquitoes associated with the indirect flight muscles would result in a flightless female mosquito. Using CRISPR-Cas9 we generated loss-of-function mutations in several genes hypothesized to control flight in mosquitoes, including actin (AeAct-4) and myosin (myo-fem) genes expressed specifically in the female flight muscle. Genetic knockout of these genes resulted in 100% flightless females, with homozygous males able to fly, mate, and produce offspring, albeit at a reduced rate when compared to wild type males. Interestingly, we found that while AeAct-4 was haplosufficient, with most heterozygous individuals capable of flight, this was not the case for myo-fem, where about half of individuals carrying only one intact copy could not fly. These findings lay the groundwork for developing novel mechanisms of controlling Ae. aegypti populations, and our results suggest that this mechanism could be applicable to other vector species of mosquito.


Assuntos
Aedes/genética , Sistemas CRISPR-Cas , Inseticidas/farmacologia , Controle de Mosquitos , Mosquitos Vetores/genética , Infecção por Zika virus/prevenção & controle , Zika virus/fisiologia , Aedes/fisiologia , Aedes/virologia , Animais , Feminino , Voo Animal , Técnicas de Inativação de Genes , Humanos , Masculino , Mosquitos Vetores/fisiologia , Mosquitos Vetores/virologia , Fenótipo , Infecção por Zika virus/transmissão , Infecção por Zika virus/virologia
10.
PLoS Pathog ; 16(12): e1009068, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33382858

RESUMO

Originating from African forests, Zika virus (ZIKV) has now emerged worldwide in urbanized areas, mainly transmitted by Aedes aegypti mosquitoes. Although Aedes albopictus can transmit ZIKV experimentally and was suspected to be a ZIKV vector in Central Africa, the potential of this species to sustain virus transmission was yet to be uncovered until the end of 2019, when several autochthonous transmissions of the virus vectored by Ae. albopictus occurred in France. Aside from these few locally acquired ZIKV infections, most territories colonized by Ae. albopictus have been spared so far. The risk level of ZIKV emergence in these areas remains however an open question. To assess Ae. albopictus' vector potential for ZIKV and identify key virus outbreak predictors, we built a complete framework using the complementary combination of (i) dose-dependent experimental Ae. albopictus exposure to ZIKV followed by time-dependent assessment of infection and systemic infection rates, (ii) modeling of intra-human ZIKV viremia dynamics, and (iii) in silico epidemiological simulations using an Agent-Based Model. The highest risk of transmission occurred during the pre-symptomatic stage of the disease, at the peak of viremia. At this dose, mosquito infection probability was estimated to be 20%, and 21 days were required to reach the median systemic infection rates. Mosquito population origin, either temperate or tropical, had no impact on infection rates or intra-host virus dynamic. Despite these unfavorable characteristics for transmission, Ae. albopictus was still able to trigger and yield large outbreaks in a simulated environment in the presence of sufficiently high mosquito biting rates. Our results reveal a low but existing epidemic potential of Ae. albopictus for ZIKV, that might explain the absence of large scale ZIKV epidemics so far in territories occupied only by Ae. albopictus. They nevertheless support active surveillance and eradication programs in these territories to maintain the risk of emergence to a low level.


Assuntos
Mosquitos Vetores/metabolismo , Mosquitos Vetores/virologia , Infecção por Zika virus/transmissão , Aedes/metabolismo , Aedes/virologia , Animais , Surtos de Doenças , Vetores de Doenças , Epidemias , Humanos , Modelos Teóricos , Saliva/virologia , Carga Viral , Viremia/transmissão , Zika virus/patogenicidade , Infecção por Zika virus/epidemiologia , Infecção por Zika virus/virologia
12.
J Immunol ; 205(11): 3083-3094, 2020 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-33139490

RESUMO

Vertical transmission of the Zika virus (ZIKV) causes severe fetal defects, but the exact pathogenic mechanism is unclear. We identified up to a 10,480-fold higher expression of viral attachment factors AXL, GAS6, and PROS1 and a 3880-fold increase in ZIKV infectiousness/propagation in human term decidual stromal cells versus trophoblasts. Moreover, levels of viral attachment factors and ZIKV are significantly increased, whereas expression of innate immune response genes are significantly decreased, in human first trimester versus term decidual cells. ZIKV-infected decidual cell supernatants increased cytotrophoblasts infection up to 252-fold compared with directly infected cytotrophoblasts. Tizoxanide treatment efficiently inhibited Zika infection in both maternal and fetal cells. We conclude that ZIKV permissiveness, as well as innate immune responsiveness of human decidual cells, are gestational age dependent, and decidual cells augment ZIKV infection of primary human cytotrophoblast cultures, which are otherwise ZIKV resistant. Human decidual cells may act as reservoirs for trimester-dependent placental transmission of ZIKV, accounting for the higher Zika infection susceptibility and more severe fetal sequelae observed in early versus late pregnancy. Moreover, tizoxanide is a promising agent in preventing perinatal Zika transmission as well as other RNA viruses such as coronavirus.


Assuntos
Decídua , Idade Gestacional , Imunidade Inata , Transmissão Vertical de Doença Infecciosa , Complicações Infecciosas na Gravidez , Infecção por Zika virus , Zika virus/imunologia , Animais , Chlorocebus aethiops , Decídua/imunologia , Decídua/patologia , Decídua/virologia , Feminino , Humanos , Gravidez , Complicações Infecciosas na Gravidez/imunologia , Complicações Infecciosas na Gravidez/patologia , Trofoblastos , Células Vero , Infecção por Zika virus/imunologia , Infecção por Zika virus/patologia , Infecção por Zika virus/transmissão
13.
Cell Rep ; 33(5): 108339, 2020 11 03.
Artigo em Inglês | MEDLINE | ID: mdl-33147451

RESUMO

Here, we report our studies of immune-mediated regulation of Zika virus (ZIKV), herpes simplex virus 1 (HSV-1), and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in the human cornea. We find that ZIKV can be transmitted via corneal transplantation in mice. However, in human corneal explants, we report that ZIKV does not replicate efficiently and that SARS-CoV-2 does not replicate at all. Additionally, we demonstrate that type III interferon (IFN-λ) and its receptor (IFNλR1) are expressed in the corneal epithelium. Treatment of human corneal explants with IFN-λ, and treatment of mice with IFN-λ eye drops, upregulates antiviral interferon-stimulated genes. In human corneal explants, blockade of IFNλR1 enhances replication of ZIKV and HSV-1 but not SARS-CoV-2. In addition to an antiviral role for IFNλR1 in the cornea, our results suggest that the human cornea does not support SARS-CoV-2 infection despite expression of ACE2, a SARS-CoV-2 receptor, in the human corneal epithelium.


Assuntos
Betacoronavirus/fisiologia , Córnea/virologia , Infecções por Coronavirus/transmissão , Herpesvirus Humano 1/fisiologia , Interferons/imunologia , Pneumonia Viral/transmissão , Zika virus/fisiologia , Animais , Betacoronavirus/imunologia , Córnea/imunologia , Infecções por Coronavirus/imunologia , Infecções por Coronavirus/virologia , Herpes Simples/imunologia , Herpes Simples/transmissão , Herpes Simples/virologia , Humanos , Camundongos , Pandemias , Pneumonia Viral/imunologia , Pneumonia Viral/virologia , Replicação Viral/fisiologia , Infecção por Zika virus/imunologia , Infecção por Zika virus/transmissão , Infecção por Zika virus/virologia
14.
BMC Public Health ; 20(1): 1385, 2020 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-32912177

RESUMO

BACKGROUND: In El Salvador, Aedes aegypti mosquitoes transmitting Zika and other arboviruses use water storage containers as important oviposition sites. Promotion of water storage container cleaning is a key element of prevention programs. We explored community perceptions surrounding cleaning practices among pregnant women, male partners of pregnant women, and women likely to become pregnant. METHODS: Researchers conducted 11 focus groups and 12 in-depth interviews which included individual elicitations of Zika prevention measures practiced in the community. Focus group participants rated 18 images depicting Zika-related behaviors according to effectiveness and feasibility in the community context, discussed influencing determinants, voted on community intentions to perform prevention behaviors, and performed washbasin cleaning simulations. In-depth interviews with male partners of pregnant women used projective techniques with images to explore their perceptions on a subset of Zika prevention behaviors. RESULTS: General cleaning of the home, to ensure a healthy environment, was a strong community norm. In this context, participants gave water storage container cleaning a high rating, for both its effectiveness and feasibility. Participants were convinced that they cleaned their water storage containers effectively against Zika, but their actual skills were inadequate to destroy Aedes aegypti eggs. A further constraint was the schedule of water availability. Even during pregnancy, male partners rarely cleaned water storage containers because water became available in homes when they were at work. Furthermore, prevailing gender norms did not foster male participation in domestic cleaning activities. Despite these factors, many men were willing to provide substantial support with cleaning when their partners were pregnant, in order to protect their family. CONCLUSIONS: Behavior change programs for the prevention of Zika and other arboviruses need to improve community members' mosquito egg destruction skills rather than perpetuate the promotion of non-specific cleaning in and around the home as effective. Egg elimination must be clearly identified as the objective of water storage container maintenance and programs should highlight the effective techniques to achieve this goal. In addition, programs must build the skills of family members who support pregnant women to maintain the frequency of effective egg destruction in all water storage containers of the home.


Assuntos
Aedes/virologia , Conhecimentos, Atitudes e Prática em Saúde , Controle de Mosquitos/métodos , Abastecimento de Água , Água , Infecção por Zika virus/prevenção & controle , Zika virus , Adolescente , Adulto , Animais , El Salvador , Feminino , Grupos Focais , Humanos , Masculino , Pessoa de Meia-Idade , Gravidez , Pesquisa Qualitativa , Características de Residência , Adulto Jovem , Zika virus/crescimento & desenvolvimento , Infecção por Zika virus/transmissão , Infecção por Zika virus/virologia
15.
PLoS Negl Trop Dis ; 14(9): e0008640, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32986701

RESUMO

Several hundred thousand Zika cases have been reported across the Americas since 2015. Incidence of infection was likely much higher, however, due to a high frequency of asymptomatic infection and other challenges that surveillance systems faced. Using a hierarchical Bayesian model with empirically-informed priors, we leveraged multiple types of Zika case data from 15 countries to estimate subnational reporting probabilities and infection attack rates (IARs). Zika IAR estimates ranged from 0.084 (95% CrI: 0.067-0.096) in Peru to 0.361 (95% CrI: 0.214-0.514) in Ecuador, with significant subnational variability in every country. Totaling infection estimates across these and 33 other countries and territories, our results suggest that 132.3 million (95% CrI: 111.3-170.2 million) people in the Americas had been infected by the end of 2018. These estimates represent the most extensive attempt to determine the size of the Zika epidemic in the Americas, offering a baseline for assessing the risk of future Zika epidemics in this region.


Assuntos
Infecção por Zika virus/epidemiologia , América/epidemiologia , Infecções Assintomáticas/epidemiologia , Teorema de Bayes , Equador/epidemiologia , Epidemias , Humanos , Incidência , Peru/epidemiologia , Zika virus , Infecção por Zika virus/transmissão , Infecção por Zika virus/virologia
16.
PLoS Negl Trop Dis ; 14(9): e0008527, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32898136

RESUMO

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.


Assuntos
Aedes/virologia , Saliva/virologia , Infecção por Zika virus/transmissão , Animais , Brasil , Mordeduras e Picadas de Insetos/virologia , Mosquitos Vetores/virologia , Estações do Ano , Temperatura , Distribuição Tecidual , Carga Viral , Zika virus
17.
Rev Prat ; 70(3): 329-332, 2020 Mar.
Artigo em Francês | MEDLINE | ID: mdl-32877071

RESUMO

Zika virus infection: what advice in post-epidemic situation? Zika virus transmission is vector-borne, but it can also be sexual. The Zika disease contracted by an adult or child is most often mild but infection of the woman during pregnancy can lead to severe neurological congenital lesions. The Zika virus continues to circulate in many parts of the world. Risk of infection during travel is low but cannot be overlooked. An infected man can be infectious, during sexual intercourse, up to 3 months after contracting the disease. Information of pregnant women and couples with a child project is warranted if at least one of the two trips or has travelled in Zika virus transmission zone. Laboratory serologic tests can be used to determine if the partners have been infected and to verify, through the investigation of the virus in the semen, that there is no risk of sexual transmission.


Assuntos
Epidemias , Complicações Infecciosas na Gravidez , Infecção por Zika virus , Zika virus , Adulto , Criança , Feminino , Humanos , Masculino , Gravidez , Viagem , Infecção por Zika virus/epidemiologia , Infecção por Zika virus/prevenção & controle , Infecção por Zika virus/transmissão
18.
PLoS Negl Trop Dis ; 14(7): e0008438, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32663213

RESUMO

BACKGROUND: Since 2015, Zika virus (ZIKV) outbreaks have occurred in the Americas and the Pacific involving mosquito-borne and sexual transmission. ZIKV has also emerged as a risk to global blood transfusion safety. Aedes aegypti, a mosquito well established in north and some parts of central and southern Queensland, Australia, transmits ZIKV. Aedes albopictus, another potential ZIKV vector, is a threat to mainland Australia. Since these conditions create the potential for local transmission in Australia and a possible uncertainty in the effectiveness of blood donor risk-mitigation programs, we investigated the possible impact of mosquito-borne and sexual transmission of ZIKV in Australia on local blood transfusion safety. METHODOLOGY/PRINCIPAL FINDINGS: We estimated 'best-' and 'worst-' case scenarios of monthly reproduction number (R0) for both transmission pathways of ZIKV from 1996-2015 in 11 urban or regional population centres, by varying epidemiological and entomological estimates. We then estimated the attack rate and subsequent number of infectious people to quantify the ZIKV transfusion-transmission risk using the European Up-Front Risk Assessment Tool. For all scenarios and with both vector species R0 was lower than one for ZIKV transmission. However, a higher risk of a sustained outbreak was estimated for Cairns, Rockhampton, Thursday Island, and theoretically in Darwin during the warmest months of the year. The yearly estimation of the risk of transmitting ZIKV infection by blood transfusion remained low through the study period for all locations, with the highest potential risk estimated in Darwin. CONCLUSIONS/SIGNIFICANCE: Given the increasing demand for plasma products in Australia, the current strategy of restricting donors returning from infectious disease outbreak regions to source plasma collection provides a simple and effective risk management approach. However, if local transmission was suspected in the main urban centres of Australia, potentially facilitated by the geographic range expansion of Ae. aegypti or Ae. albopictus, this mitigation strategy would need urgent review.


Assuntos
Aedes/virologia , Doadores de Sangue , Segurança do Sangue/normas , Mosquitos Vetores/virologia , Doenças Virais Sexualmente Transmissíveis/transmissão , Infecção por Zika virus/transmissão , Animais , Austrália/epidemiologia , Doenças Transmissíveis Emergentes/epidemiologia , Surtos de Doenças , Humanos , Modelos Biológicos , Saúde Pública , Reprodutibilidade dos Testes , Doenças Virais Sexualmente Transmissíveis/sangue , Doenças Virais Sexualmente Transmissíveis/epidemiologia , Zika virus/fisiologia , Infecção por Zika virus/epidemiologia , Infecção por Zika virus/virologia
19.
PLoS One ; 15(7): e0234959, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32663230

RESUMO

The economic and social impacts due to diseases transmitted by mosquitoes in the latest years have been significant. Currently, no specific treatment or commercial vaccine exists for the control and prevention of arboviruses, thereby making entomological characterization fundamental in combating diseases such as dengue, chikungunya, and Zika. The morphological identification of mosquitos includes a visual exam of the samples. It is time consuming and requires adequately trained professionals. Accordingly, the development of a new automated method for realizing mosquito-perception and -classification is becoming increasingly essential. Therefore, in this study, a computational model based on a convolutional neural network (CNN) was developed to extract features from the images of mosquitoes and then classify the species Aedes aegypti, Aedes albopictus, and Culex quinquefasciatus. In addition, the model was trained to detect the mosquitoes of the genus Aedes. To train CNNs to perform the automatic morphological classification of mosquitoes, a dataset, which included 7,561 images of the target mosquitoes and 1,187 images of other insects, was acquired. Various neural networks, such as Xception and DenseNet, were used for developing the automatic-classification model based on images. A structured optimization process of random search and grid search was developed to select the hyperparameters set and increase the accuracy of the model. In addition, strategies to eliminate overfitting were implemented to increase the generalization of the model. The optimized model, during the test phase, obtained the balanced accuracy (BA) of 93.5% in classifying the target mosquitoes and other insects and the BA of 97.3% in detecting the mosquitoes of the genus Aedes in comparison to Culex. The results provide fundamental information for performing the automatic morphological classification of mosquito species. Using a CNN-embedded entomological tool is a valuable and accessible resource for health workers and non-taxonomists for identifying insects that can transmit infectious diseases.


Assuntos
Arbovirus/classificação , Culicidae/classificação , Processamento de Imagem Assistida por Computador/métodos , Aedes/virologia , Animais , Automação Laboratorial/métodos , Febre de Chikungunya/transmissão , Vírus Chikungunya/genética , Culex/virologia , Culicidae/genética , Dengue/transmissão , Vírus da Dengue/genética , Feminino , Masculino , Mosquitos Vetores/virologia , Zika virus/genética , Infecção por Zika virus/transmissão
20.
Proc Biol Sci ; 287(1930): 20200119, 2020 07 08.
Artigo em Inglês | MEDLINE | ID: mdl-32635867

RESUMO

Mosquito-borne Zika virus (ZIKV) transmission has almost exclusively been detected in the tropics despite the distributions of its primary vectors extending farther into temperate regions. Therefore, it is unknown whether ZIKV's range has reached a temperature-dependent limit, or if it can spread into temperate climates. Using field-collected mosquitoes for biological relevance, we found that two common temperate mosquito species, Aedes albopictus and Ochlerotatus detritus, were competent for ZIKV. We orally exposed mosquitoes to ZIKV and held them at between 17 and 31°C, estimated the time required for mosquitoes to become infectious, and applied these data to a ZIKV spatial risk model. We identified a minimum temperature threshold for the transmission of ZIKV by mosquitoes between 17 and 19°C. Using these data, we generated standardized basic reproduction number R0-based risk maps and we derived estimates for the length of the transmission season for recent and future climate conditions. Our standardized R0-based risk maps show potential risk of ZIKV transmission beyond the current observed range in southern USA, southern China and southern European countries. Transmission risk is simulated to increase over southern and Eastern Europe, northern USA and temperate regions of Asia (northern China, southern Japan) in future climate scenarios.


Assuntos
Mosquitos Vetores , Temperatura , Infecção por Zika virus/transmissão , Aedes , Animais , Número Básico de Reprodução , Clima , Zika virus
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