RESUMEN
Chikungunya virus (CHIKV) is a rapidly spreading re-emergent virus transmitted from mosquitoes to humans. The emergence of epidemic variants has been associated with changes in the viral genome, such as the duplication of repeated sequences in the 3' untranslated region (UTR). Indeed, blocks of repeated sequences seemingly favor RNA recombination, providing the virus with a unique ability to continuously change the 3'UTR architecture during host switching. In this work, we provide experimental data on the molecular mechanism of RNA recombination and describe specific sequence and structural elements in the viral 3'UTR that favor template switching of the viral RNA-dependent RNA polymerase on the 3'UTR. Furthermore, we found that a 3'UTR deletion mutant that exhibits markedly delayed replication in mosquito cells and impaired transmission in vivo, recombines in reference laboratory strains of mosquitoes. Altogether, our data provide novel experimental evidence indicating that RNA recombination can act as a nucleic acid repair mechanism to add repeated sequences that are associated to high viral fitness in mosquito during chikungunya virus replication.
Asunto(s)
Regiones no Traducidas 3' , Virus Chikungunya , Genoma Viral , ARN Viral , Recombinación Genética , Replicación Viral , Virus Chikungunya/genética , Regiones no Traducidas 3'/genética , ARN Viral/genética , ARN Viral/metabolismo , Animales , Replicación Viral/genética , Fiebre Chikungunya/virología , Fiebre Chikungunya/genética , Fiebre Chikungunya/transmisión , Humanos , Aedes/virología , Aedes/genética , ARN Polimerasa Dependiente del ARN/genética , ARN Polimerasa Dependiente del ARN/metabolismo , Línea CelularRESUMEN
Zika (ZIKV) and chikungunya (CHIKV) are arboviruses that cause infections in humans and can cause clinical complications, representing a worldwide public health problem. Aedes aegypti is the primary vector of these pathogens and Culex quinquefasciatus may be a potential ZIKV vector. This study aimed to evaluate fecundity, fertility, survival, longevity, and blood feeding activity in Ae. aegypti after exposure to ZIKV and CHIKV and, in Cx. quinquefasciatus exposed to ZIKV. Three colonies were evaluated: AeCamp (Ae. aegypti-field), RecL (Ae. aegypti-laboratory) and CqSLab (Cx. quinquefasciatus-laboratory). Seven to 10 days-old females from these colonies were exposed to artificial blood feeding with CHIKV or ZIKV. CHIKV caused reduction in fecundity and fertility in AeCamp and reduction in survival and fertility in RecL. ZIKV impacted survival in RecL, fertility in AeCamp and, fecundity and fertility in CqSLab. Both viruses had no effect on blood feeding activity. These results show that CHIKV produces a higher biological cost in Ae. aegypti, compared to ZIKV, and ZIKV differently alters the biological performance in colonies of Ae. aegypti and Cx. quinquefasciatus. These results provide a better understanding over the processes of virus-vector interaction and can shed light on the complexity of arbovirus transmission.
Asunto(s)
Aedes , Virus Chikungunya , Culex , Fertilidad , Mosquitos Vectores , Infección por el Virus Zika , Virus Zika , Animales , Aedes/virología , Aedes/fisiología , Virus Chikungunya/fisiología , Virus Chikungunya/patogenicidad , Virus Zika/fisiología , Virus Zika/patogenicidad , Culex/virología , Culex/fisiología , Mosquitos Vectores/virología , Mosquitos Vectores/fisiología , Femenino , Infección por el Virus Zika/transmisión , Infección por el Virus Zika/virología , Fiebre Chikungunya/transmisión , Fiebre Chikungunya/virología , Conducta Alimentaria/fisiología , Humanos , LongevidadRESUMEN
Chikungunya virus (CHIKV) has emerged as a significant public health concern due to its rapid spread and potential for causing debilitating epidemics. In Argentina, the virus has garnered attention since its introduction to the Americas in 2013, due to its growing incidence and impact in neighbouring countries. Here we present a comprehensive analysis of the spatiotemporal dynamics of CHIKV in Argentina, focusing on the evolutionary trajectory of its genetic variants. Through a combination of active surveillance, screening of historical and recent samples, and whole-genome sequencing, we traced the evolutionary history of CHIKV lineages circulating within the country. Our results reveal that two distinct genotypes circulated in Argentina: The Asian lineage during the 2016 epidemic and the ECSA lineage in 2023. This distribution reflects the dominance of particular variants across Latin America. Since 2023, the ECSA lineage has led to a surge in cases throughout the Americas, marking a significant shift. The replacement of lineages in the American region constitutes a major epidemiological event, potentially affecting the dynamics of virus transmission and the clinical outcomes in impacted populations. The spatiotemporal analysis highlights CHIKV's distribution across Argentina and underscores the significant role of human mobility, especially when considering recent epidemics in neighbouring countries such as Paraguay and Uruguay, which have facilitated the spread and introduction of the viral strain into different districts. By integrating epidemiological data with genomic insights, we elucidate the patterns of virus dissemination, highlighting key areas of transmission and potential factors contributing to its spread.
Asunto(s)
Fiebre Chikungunya , Virus Chikungunya , Evolución Molecular , Genotipo , Filogenia , Argentina/epidemiología , Virus Chikungunya/genética , Virus Chikungunya/clasificación , Virus Chikungunya/aislamiento & purificación , Fiebre Chikungunya/epidemiología , Fiebre Chikungunya/virología , Fiebre Chikungunya/transmisión , Humanos , Genoma Viral , América Latina/epidemiología , Secuenciación Completa del Genoma , Análisis Espacio-Temporal , Variación GenéticaRESUMEN
The Chikungunya Virus (CHIKV) already has endemic circulation in about 100 countries and the number of infected patients increases every year, due to the effectiveness of the vector and human universal susceptibility to infection. The virus can also be transmitted from mother to child, more frequently intrapartum. About 50 % of neonates with CHIKV symptoms will have neurodevelopmental delay. It is therefore an infection of worldwide concern with a great impact on people's quality of life. The objective of this work is to describe two cases of confirmed vertical transmission by chikungunya virus, one of them with intrauterine infection and death of the neonate. Neonates with vertical chikungunya infection may present with clinical sepsis in the first few days of life, which is why this is a very important diagnosis, especially during outbreaks of the infection.
Asunto(s)
Fiebre Chikungunya , Transmisión Vertical de Enfermedad Infecciosa , Humanos , Fiebre Chikungunya/transmisión , Fiebre Chikungunya/diagnóstico , Recién Nacido , Femenino , Embarazo , Virus Chikungunya , Resultado Fatal , Complicaciones Infecciosas del Embarazo/virología , MasculinoRESUMEN
OBJECTIVES: To monitor the oviposition activity of the mosquito Aedes aegypti and of dengue and chikungunya cases in four localities of temperate Argentina, during the 2023 epidemic. METHODS: During the summer and autumn of 2023, the oviposition activity of the mosquito vector was monitored weekly using ovitraps, and the arrival of cases with dengue or chikungunya in Tandil, Olavarría, Bahía Blanca and Laprida were registered. RESULTS: Monthly variations of the percentage of positive traps were similar in the first three locations; in Laprida the mosquito was not detected. On the contrary, a significant difference was observed in the percentage of total traps that ever tested positive in each locality, being higher in Olavarría (83.3%) than in Bahía Blanca (68.6%) and Tandil (48.7%). Regarding diseases, 18 imported cases of dengue and 3 of chikungunya were registered. In addition, the first autochthonous case of dengue in the region was recorded, being the southernmost until known. CONCLUSION: It is essential to raise awareness and train the members of the health systems of the new regions exposed to Ae. aegypti for early detection of cases, and to the general population to enhance prevention actions.
OBJETIVOS: Monitorear la actividad de oviposición del mosquito Aedes aegypti y de casos de dengue y chikungunya en cuatro localidades de Argentina templada, durante la epidemia del 2023. Métodos: Durante el verano y otoño del 2023, se monitoreó semanalmente mediante ovitrampas la actividad de oviposición del mosquito vector, y se registró el arribo de casos con dengue o chikungunya a Tandil, Olavarría, Bahía Blanca y Laprida. RESULTADOS: La variación mensual del porcentaje de trampas positivas fue similar en las tres primeras localidades; en Laprida no se detectó el mosquito. Por el contrario, se observó una diferencia significativa del porcentaje de trampas que alguna vez resultó positiva en cada localidad, siendo mayor en Olavarría (83%), que en Bahía Blanca (67%) y Tandil (49%). Respecto a las enfermedades, se registraron 18 casos importados de dengue y 3 de chikungunya. Además, se registró el primer caso autóctono de dengue en la región, siendo el más austral hasta el momento. Conclusión: Es imprescindible sensibilizar y capacitar a los integrantes de los sistemas de salud de las nuevas regiones expuestas al Ae. aegypti para la detección temprana de casos, y a la población en general para potenciar las acciones de prevención.
Asunto(s)
Aedes , Fiebre Chikungunya , Dengue , Mosquitos Vectores , Estaciones del Año , Argentina/epidemiología , Dengue/epidemiología , Dengue/transmisión , Dengue/prevención & control , Fiebre Chikungunya/epidemiología , Fiebre Chikungunya/transmisión , Fiebre Chikungunya/prevención & control , Animales , Aedes/virología , Aedes/fisiología , Mosquitos Vectores/fisiología , Humanos , Epidemias , Femenino , Oviposición/fisiologíaRESUMEN
The incidence of chikungunya has dramatically surged worldwide in recent decades, imposing an expanding burden on public health. In recent years, South America, particularly Brazil, has experienced outbreaks that have ravaged populations following the rapid dissemination of the chikungunya virus (CHIKV), which was first detected in 2014. The primary vector for CHIKV transmission is the urban mosquito species Aedes aegypti, which is highly prevalent throughout Brazil. However, the impact of the locally circulating CHIKV genotypes and specific combinations of local mosquito populations on vector competence remains unexplored. Here, we experimentally analyzed and compared the infectivity and transmissibility of the CHIKV-ECSA lineage recently isolated in Brazil among four Ae. aegypti populations collected from different regions of the country. When exposed to CHIKV-infected AG129 mice for blood feeding, all the mosquito populations displayed high infection rates and dissemination efficiency. Furthermore, we observed that all the populations were highly efficient in transmitting CHIKV to a vertebrate host (naïve AG129 mice) as early as eight days post-infection. These results demonstrate the high capacity of Brazilian Ae. aegypti populations to transmit the locally circulating CHIKV-ECSA lineage. This observation could help to explain the high prevalence of the CHIKV-ECSA lineage over the Asian lineage, which was also detected in Brazil in 2014. However, further studies comparing both lineages are necessary to gain a better understanding of the vector's importance in the epidemiology of CHIKV in the Americas.
Asunto(s)
Aedes , Fiebre Chikungunya , Virus Chikungunya , Mosquitos Vectores , Animales , Aedes/virología , Virus Chikungunya/genética , Virus Chikungunya/clasificación , Virus Chikungunya/fisiología , Virus Chikungunya/aislamiento & purificación , Brasil/epidemiología , Fiebre Chikungunya/transmisión , Fiebre Chikungunya/virología , Fiebre Chikungunya/epidemiología , Ratones , Mosquitos Vectores/virología , Genotipo , Femenino , FilogeniaRESUMEN
BACKGROUND: The global impact of Zika virus in Latin America has drawn renewed attention to circulating mosquito-borne viruses in this region, such as dengue and chikungunya. Our objective was to assess socio-ecological factors associated with Aedes mosquito vector density as a measure of arbovirus transmission risk in three cities of potentially recent Zika virus introduction: Ibagué, Colombia; Manta, Ecuador; and Posadas, Argentina, in order to inform disease mitigation strategies. METHODS: We sampled Aedes mosquito populations in a total of 1086 households, using indoor and peridomestic mosquito collection methods, including light traps, resting traps, traps equipped with chemical attractant and aspirators. For each sampled household, we collected socio-economic data using structured questionnaires and data on microenvironmental conditions using iButton data loggers. RESULTS: A total of 3230 female Aedes mosquitoes were collected, of which 99.8% were Aedes aegypti and 0.2% were Aedes albopictus. Mean female Aedes mosquito density per household was 1.71 (standard deviation: 2.84). We used mixed-effects generalized linear Poisson regression analyses to identify predictors of Aedes density, using month, neighborhood and country as random-effects variables. Across study sites, the number of household occupants [incidence rate ratio (IRR): 1.08, 95% confidence interval (CI): 1.01-1.14], presence of entry points for mosquitoes into the household (IRR: 1.51, 95% CI: 1.30-1.76) and presence of decorative vegetation (IRR: 1.52, 95% CI: 1.22-1.88) were associated with higher Aedes density; while being in the highest wealth tertile of household wealth (IRR: 0.78, 95% CI: 0.66-0.92), knowledge of how arboviruses are transmitted (IRR: 0.94, 95% CI: 0.89-1.00) and regular emptying of water containers by occupants (IRR: 0.79, 95% CI: 0.67-0.92) were associated with lower Aedes density. CONCLUSIONS: Our study addresses the complexities of arbovirus vectors of global significance at the interface between human and mosquito populations. Our results point to several predictors of Aedes mosquito vector density in countries with co-circulation of multiple Aedes-borne viruses, and point to modifiable risk factors that may be useful for disease prevention and control.
Asunto(s)
Aedes/virología , Distribución Animal , Infecciones por Arbovirus/transmisión , Arbovirus/patogenicidad , Mosquitos Vectores/virología , Aedes/fisiología , Animales , Argentina , Fiebre Chikungunya/transmisión , Ciudades , Colombia , Dengue/transmisión , Ecuador , Femenino , Humanos , Mosquitos Vectores/fisiología , Factores de Riesgo , Infección por el Virus Zika/transmisiónRESUMEN
BACKGROUND: Dengue, Zika and chikungunya are arboviruses of significant public health importance that are transmitted by Aedes aegypti and Aedes albopictus mosquitoes. In Colombia, where dengue is hyperendemic, and where chikungunya and Zika were introduced in the last decade, more than half of the population lives in areas at risk. The objective of this study was to characterize Aedes spp. vectors and study their natural infection with dengue, Zika and chikungunya in Ibagué, a Colombian city and capital of the department of Tolima, with case reports of simultaneous circulation of these three arboviruses. METHODS: Mosquito collections were carried out monthly between June 2018 and May 2019 in neighborhoods with different levels of socioeconomic status. We used the non-parametric Friedman, Mann-Whitney and Kruskal-Wallis tests to compare mosquito density distributions. We applied logistic regression analyses to identify associations between mosquito density and absence/presence of breeding sites, and the Spearman correlation coefficient to analyze the possible relationship between climatic variables and mosquito density. RESULTS: We collected Ae. aegypti in all sampled neighborhoods and found for the first time Ae. albopictus in the city of Ibagué. A greater abundance of mosquitoes was collected in neighborhoods displaying low compared to high socioeconomic status as well as in the intradomicile compared to the peridomestic space. Female mosquitoes predominated over males, and most of the test females had fed on human blood. In total, four Ae. aegypti pools (3%) were positive for dengue virus (serotype 1) and one pool for chikungunya virus (0.8%). Interestingly, infected females were only collected in neighborhoods of low socioeconomic status, and mostly in the intradomicile space. CONCLUSIONS: We confirmed the co-circulation of dengue (serotype 1) and chikungunya viruses in the Ae. aegypti population in Ibagué. However, Zika virus was not detected in any mosquito sample, 3 years after its introduction into the country. The positivity for dengue and chikungunya viruses, predominance of mosquitoes in the intradomicile space and the high proportion of females fed on humans highlight the high risk for arbovirus transmission in Ibagué, but may also provide an opportunity for establishing effective control strategies.
Asunto(s)
Aedes/virología , Arbovirus/aislamiento & purificación , Fiebre Chikungunya/epidemiología , Dengue/epidemiología , Mosquitos Vectores/virología , Infección por el Virus Zika/epidemiología , Animales , Arbovirus/genética , Fiebre Chikungunya/transmisión , Virus Chikungunya/genética , Ciudades/epidemiología , Colombia/epidemiología , Dengue/transmisión , Virus del Dengue/genética , Composición Familiar , Femenino , Humanos , Masculino , Salud Pública , Virus Zika/genética , Infección por el Virus Zika/transmisiónRESUMEN
In 2015-2016, simultaneous circulation of dengue, Zika and chikungunya in the municipality of Rio de Janeiro (Brazil) was reported. We conducted an ecological study to analyse the spatial distribution of dengue, Zika and chikungunya cases and to investigate socioeconomic factors associated with individual and combined disease incidence in 2015-2016. We then constructed thematic maps and analysed the bivariate global Moran indices. Classical and spatial models were used. A distinct spatial distribution pattern for dengue, Zika and chikungunya was identified in the municipality of Rio de Janeiro. The bivariate global Moran indices (P < 0.05) revealed negative spatial correlations between rates of dengue, Zika, chikungunya and combined arboviruses incidence and social development index and mean income. The regression models (P < 0.05) identified a negative relationship between mean income and each of these rates and between sewage and Zika incidence rates, as well as a positive relationship between urban areas and chikungunya incidence rates. In our study, spatial analysis techniques helped to identify high-risk and social determinants at the local level for the three arboviruses. Our findings may aid in backing effective interventions for the prevention and control of epidemics of these diseases.
Asunto(s)
Fiebre Chikungunya/epidemiología , Dengue/epidemiología , Factores Socioeconómicos , Infección por el Virus Zika/epidemiología , Aedes/virología , Animales , Brasil/epidemiología , Fiebre Chikungunya/transmisión , Ciudades , Estudios Transversales , Dengue/transmisión , Epidemias , Humanos , Incidencia , Insectos Vectores/virología , Modelos Estadísticos , Análisis Espacial , Infección por el Virus Zika/transmisiónRESUMEN
Zika virus (ZIKV) and chikungunya virus (CHIKV) were recently introduced into the Americas resulting in significant disease burdens. Understanding their spatial and temporal dynamics at the subnational level is key to informing surveillance and preparedness for future epidemics. We analyzed anonymized line list data on approximately 105,000 Zika virus disease and 412,000 chikungunya fever suspected and laboratory-confirmed cases during the 2014-2017 epidemics. We first determined the week of invasion in each city. Out of 1,122, 288 cities met criteria for epidemic invasion by ZIKV and 338 cities by CHIKV. We analyzed risk factors for invasion using linear and logistic regression models. We also estimated that the geographic origin of both epidemics was located in Barranquilla, north Colombia. We assessed the spatial and temporal invasion dynamics of both viruses to analyze transmission between cities using a suite of (i) gravity models, (ii) Stouffer's rank models, and (iii) radiation models with two types of distance metrics, geographic distance and travel time between cities. Invasion risk was best captured by a gravity model when accounting for geographic distance and intermediate levels of density dependence; Stouffer's rank model with geographic distance performed similarly well. Although a few long-distance invasion events occurred at the beginning of the epidemics, an estimated distance power of 1.7 (95% CrI: 1.5-2.0) from the gravity models suggests that spatial spread was primarily driven by short-distance transmission. Similarities between the epidemics were highlighted by jointly fitted models, which were preferred over individual models when the transmission intensity was allowed to vary across arboviruses. However, ZIKV spread considerably faster than CHIKV.
Asunto(s)
Fiebre Chikungunya , Epidemias/estadística & datos numéricos , Infección por el Virus Zika , Fiebre Chikungunya/epidemiología , Fiebre Chikungunya/transmisión , Virus Chikungunya , Colombia/epidemiología , Humanos , Análisis Espacio-Temporal , Virus Zika , Infección por el Virus Zika/epidemiología , Infección por el Virus Zika/transmisiónRESUMEN
BACKGROUND: The introduction of the bacterium Wolbachia (wMel strain) into Aedes aegypti mosquitoes reduces their capacity to transmit dengue and other arboviruses. Evidence of a reduction in dengue case incidence following field releases of wMel-infected Ae. aegypti has been reported previously from a cluster randomised controlled trial in Indonesia, and quasi-experimental studies in Indonesia and northern Australia. METHODOLOGY/PRINCIPAL FINDINGS: Following pilot releases in 2015-2016 and a period of intensive community engagement, deployments of adult wMel-infected Ae. aegypti mosquitoes were conducted in Niterói, Brazil during 2017-2019. Deployments were phased across four release zones, with a total area of 83 km2 and a residential population of approximately 373,000. A quasi-experimental design was used to evaluate the effectiveness of wMel deployments in reducing dengue, chikungunya and Zika incidence. An untreated control zone was pre-defined, which was comparable to the intervention area in historical dengue trends. The wMel intervention effect was estimated by controlled interrupted time series analysis of monthly dengue, chikungunya and Zika case notifications to the public health surveillance system before, during and after releases, from release zones and the control zone. Three years after commencement of releases, wMel introgression into local Ae. aegypti populations was heterogeneous throughout Niterói, reaching a high prevalence (>80%) in the earliest release zone, and more moderate levels (prevalence 40-70%) elsewhere. Despite this spatial heterogeneity in entomological outcomes, the wMel intervention was associated with a 69% reduction in dengue incidence (95% confidence interval 54%, 79%), a 56% reduction in chikungunya incidence (95%CI 16%, 77%) and a 37% reduction in Zika incidence (95%CI 1%, 60%), in the aggregate release area compared with the pre-defined control area. This significant intervention effect on dengue was replicated across all four release zones, and in three of four zones for chikungunya, though not in individual release zones for Zika. CONCLUSIONS/SIGNIFICANCE: We demonstrate that wMel Wolbachia can be successfully introgressed into Ae. aegypti populations in a large and complex urban setting, and that a significant public health benefit from reduced incidence of Aedes-borne disease accrues even where the prevalence of wMel in local mosquito populations is moderate and spatially heterogeneous. These findings are consistent with the results of randomised and non-randomised field trials in Indonesia and northern Australia, and are supportive of the Wolbachia biocontrol method as a multivalent intervention against dengue, chikungunya and Zika.
Asunto(s)
Aedes/microbiología , Aedes/virología , Fiebre Chikungunya/transmisión , Dengue/transmisión , Control de Mosquitos/métodos , Wolbachia/fisiología , Infección por el Virus Zika/transmisión , Aedes/fisiología , Animales , Brasil/epidemiología , Fiebre Chikungunya/epidemiología , Fiebre Chikungunya/virología , Virus Chikungunya/fisiología , Dengue/epidemiología , Dengue/virología , Virus del Dengue/fisiología , Femenino , Humanos , Incidencia , Masculino , Mosquitos Vectores/microbiología , Mosquitos Vectores/fisiología , Mosquitos Vectores/virología , Virus Zika/fisiología , Infección por el Virus Zika/epidemiología , Infección por el Virus Zika/virologíaRESUMEN
Since introduction into Brazil in 2014, chikungunya virus (CHIKV) has presented sustained transmission, although much is unknown about its circulation in the midwestern states. Here, we analyze 24 novel partial and near complete CHIKV genomes from Cuiaba, an urban metropolis located in the Brazilian midwestern state of Mato Grosso (MT). Nanopore technology was used for sequencing CHIKV complete genomes. Phylogenetic and epidemiological approaches were used to explore the recent spatio-temporal evolution and spread of the CHIKV-ECSA genotype in Midwest Brazil as well as in the Americas. Epidemiological data revealed a reduction in the number of reported cases over 2018-2020, likely as a consequence of a gradual accumulation of herd-immunity. Phylogeographic reconstructions revealed that at least two independent introductions of the ECSA lineage occurred in MT from a dispersion event originating in the northeastern region and suggest that the midwestern Brazilian region appears to have acted as a source of virus transmission towards Paraguay, a bordering South American country. Our results show a complex dynamic of transmission between epidemic seasons and suggest a possible role of Brazil as a source for international dispersion of the CHIKV-ECSA genotype to other countries in the Americas.
Asunto(s)
Fiebre Chikungunya/epidemiología , Fiebre Chikungunya/transmisión , Virus Chikungunya/genética , Genoma Viral/genética , Adolescente , Adulto , Teorema de Bayes , Brasil/epidemiología , Fiebre Chikungunya/diagnóstico , Virus Chikungunya/aislamiento & purificación , Monitoreo Epidemiológico , Femenino , Genotipo , Humanos , Masculino , Persona de Mediana Edad , Filogenia , Análisis Espacio-Temporal , Secuenciación Completa del Genoma , Adulto JovenRESUMEN
BACKGROUND: Chikungunya is an arbovirus, transmitted by Aedes mosquitoes, which emerged in the Americas in 2013 and spread rapidly to almost every country on this continent. In Brazil, where the first cases were detected in 2014, it currently has reached all regions of this country and more than 900,000 cases were reported. The clinical spectrum of chikungunya ranges from an acute self-limiting form to disabling chronic forms. The purpose of this study was to estimate the seroprevalence of chikungunya infection in a large Brazilian city and investigate the association between viral circulation and living condition. METHODOLOGY/PRINCIPAL FINDINGS: We conducted a population-based ecological study in selected Sentinel Areas (SA) through household interviews and a serologic survey in 2016/2017. The sample was of 1,981 individuals randomly selected. The CHIKV seroprevalence was 22.1% (17.1 IgG, 2.3 IgM, and 1.4 IgG and IgM) and varied between SA from 2.0% to 70.5%. The seroprevalence was significantly lower in SA with high living conditions compared to SA with low living condition. There was a positive association between CHIKV seroprevalence and population density (r = 0.2389; p = 0.02033). CONCLUSIONS/SIGNIFICANCE: The seroprevalence in this city was 2.6 times lower than the 57% observed in a study conducted in the epicentre of the CHIKV epidemic of this same urban centre. So, the herd immunity in this general population, after four years of circulation of this agent is relatively low. It indicates that CHIKV transmission may persist in that city, either in endemic form or in the form of a new epidemic, because the vector infestation is persistent. Besides, the significantly lower seroprevalences in SA of higher Living Condition suggest that beyond the surveillance of the disease, vector control and specific actions of basic sanitation, the reduction of the incidence of this infection also depends on the improvement of the general living conditions of the population.
Asunto(s)
Anticuerpos Antivirales/sangre , Fiebre Chikungunya/epidemiología , Fiebre Chikungunya/virología , Virus Chikungunya/inmunología , Adolescente , Adulto , Anciano , Brasil/epidemiología , Fiebre Chikungunya/inmunología , Fiebre Chikungunya/transmisión , Niño , Preescolar , Enfermedades Transmisibles Emergentes/epidemiología , Enfermedades Transmisibles Emergentes/inmunología , Enfermedades Transmisibles Emergentes/transmisión , Enfermedades Transmisibles Emergentes/virología , Brotes de Enfermedades , Femenino , Humanos , Inmunidad Colectiva , Inmunoglobulina G/sangre , Inmunoglobulina M/sangre , Lactante , Masculino , Persona de Mediana Edad , Vigilancia de la Población , Estudios Seroepidemiológicos , Adulto JovenRESUMEN
OBJECTIVES: To describe and estimate the frequency of pregnancy outcomes, clinical and laboratory characteristics of vertical transmission of CHIKV in the neonate. STUDY DESIGN: We performed a systematic review evaluating the clinical presentation of perinatally-acquired CHIKV infection in neonates. The search was performed using Medline (via PubMed), LILACS, Web of Science, Scielo, Google Scholar and Open grey to identify studies assessing vertical transmission of CHIKV up to November 3, 2020. There were no search restrictions regarding the study type, the publication date or language. Studies with no documented evidence of CHIKV infection in neonates (negative RT-PCR or absence of IgM) were excluded. RESULTS: From the 227 studies initially identified, 42 were selected as follows: 28 case reports, 7 case series, 2 cross-sectional studies and 5 cohort studies, for a total of 266 CHIKV infected neonates confirmed by serological and/or molecular tests. The vertical transmission rate was 50% in the Reunion Island outbreak, which was the subject of the majority of the studies; the premature delivery were reported in 19 (45.2%) studies; the rate of fetal distress was 19.6% of infected babies and fetal loss occurred in 2% of the cases. Approximately 68.7% of newborns were diagnosed with encephalopathy or encephalitis after perinatally acquired CHIKV. Most of the infected neonates were born healthy, developing CHIKV sepsis clinical syndrome within the first week of life. CONCLUSIONS: We alert neonatologists to the late manifestations of neonatal CHIKV infection, relevant to the management and reduction of morbidity. A limitation of our review was that it was not possible to carry out meta-analysis due to differences in study design and the small number of participants.
Asunto(s)
Fiebre Chikungunya/transmisión , Transmisión Vertical de Enfermedad Infecciosa/estadística & datos numéricos , Complicaciones Infecciosas del Embarazo/epidemiología , Adulto , Fiebre Chikungunya/epidemiología , Fiebre Chikungunya/virología , Virus Chikungunya/aislamiento & purificación , Virus Chikungunya/patogenicidad , Femenino , Humanos , Recién Nacido , Embarazo , Complicaciones Infecciosas del Embarazo/virologíaRESUMEN
In 2014, the chikungunya virus (CHIKV) was detected for the first time in Mexico, the identified strain was the one corresponding to the Asian genotype which was phylogenetically grouped with the strains that circulated in the British Virgin Islands outbreak and was later classified with lineages of Caribbean strains. In three years, 13,569 cases of chikungunya were registered in Mexico. Although the transmission and spread of the virus are now considered a moderate risk, the danger that the virus reemerges is not ruled out due to the infestation of Aedes mosquitoes. In this study, we reviewed the chikungunya fever (CHIKF) cases reported between 2014 and 2016 to reanalyze the data. Seventeen cases were selected from different states where the circulation of the virus had been reported. Statistical data were analyzed and a retrospective analysis was carried out. Nucleic acid sequences were determined of these 17 samples. 2015 was the year with the highest number of cases (92.8%) and they were detected in 28 states of the country. There is a predominance of females, and the most affected age group was between 25 and 44 years. In 2016, CHIKV genotypes were not known, in this study the presence of the Asian genotype of Caribbean lineage was confirmed. The presence of the West African and ECSA genotypes was phylogenetically ruled out. The sequences obtained were deposited in GeneBank.
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Fiebre Chikungunya/epidemiología , Virus Chikungunya/genética , Adolescente , Adulto , Fiebre Chikungunya/transmisión , Fiebre Chikungunya/virología , Niño , Preescolar , Bases de Datos Genéticas , Brotes de Enfermedades , Femenino , Genotipo , Humanos , Masculino , México , Persona de Mediana Edad , Filogenia , Estudios Retrospectivos , Análisis de Secuencia de ADNRESUMEN
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.
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Fiebre Chikungunya/epidemiología , Enfermedades Transmisibles Emergentes/epidemiología , Dengue/epidemiología , Brotes de Enfermedades/estadística & datos numéricos , Enfermedades Endémicas/estadística & datos numéricos , Infección por el Virus Zika/epidemiología , Adolescente , Aedes/virología , Animales , Fiebre Chikungunya/prevención & control , Fiebre Chikungunya/transmisión , Fiebre Chikungunya/virología , Virus Chikungunya/aislamiento & purificación , Niño , Preescolar , Enfermedades Transmisibles Emergentes/prevención & control , Enfermedades Transmisibles Emergentes/transmisión , Enfermedades Transmisibles Emergentes/virología , Dengue/prevención & control , Dengue/transmisión , Dengue/virología , Virus del Dengue/aislamiento & purificación , Brotes de Enfermedades/prevención & control , República Dominicana/epidemiología , Enfermedades Endémicas/prevención & control , Monitoreo Epidemiológico , Femenino , Humanos , Lactante , Recién Nacido , Masculino , Control de Mosquitos , Mosquitos Vectores/virología , Análisis Espacio-Temporal , Adulto Joven , Virus Zika/aislamiento & purificación , Infección por el Virus Zika/prevención & control , Infección por el Virus Zika/transmisión , Infección por el Virus Zika/virologíaRESUMEN
OBJECTIVE: To evaluate pregnancy and neonatal outcomes, disease severity, and mother-to-child transmission of pregnant women with Chikungunya infection (CHIKV). DESIGN: Retrospective observational study. SETTING: Grenada. POPULATION: Women who gave birth during a Chikungunya outbreak between January 2014 and September 2015 were eligible. METHODS: This descriptive study investigated 731 mother-infant pairs who gave birth during a CHIKV outbreak. Women and infants underwent serological testing for CHIKV by ELISA. MAIN OUTCOME MEASURES: Primary outcomes: composite pregnancy complication (abruption, vaginal bleeding, preterm labour/cervical incompetence, cesarean delivery for fetal distress/abruption/placental abnormality or delivery for fetal distress) and composite neonatal morbidity. RESULTS: Of 416 mother-infant pairs, 150 (36%) had CHIKV during pregnancy, 135 (33%) had never had CHIKV, and 131 (31%) had CHIKV outside of pregnancy. Mean duration of joint pain was shorter among women infected during pregnancy (µ = 898 days, σ = 277 days) compared with infections outside of pregnancy (µ = 1064 days, σ = 244 days) (P < 0.0001). Rates of pregnancy complications (RR = 0.76, P = 0.599), intrapartum complications (RR = 1.50, P = 0.633), and neonatal outcomes were otherwise similar. Possible mother-to-child transmission occurred in two (1.3%) mother-infant pairs and two of eight intrapartum infections (25%). CONCLUSION: CHIKV infection during pregnancy may be protective against long-term joint pain sequelae that are often associated with acute CHIKV infection. Infection during pregnancy did not appear to pose a risk for pregnancy complications or neonatal health, but maternal infection just prior to delivery might have increased risk of mother-to-child transmission of CHIKV. TWEETABLE ABSTRACT: Chikungunya infection did not increase risk of pregnancy complications or adverse neonatal outcomes, unless infection was just prior to delivery.
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Fiebre Chikungunya , Parto Obstétrico , Sufrimiento Fetal , Transmisión Vertical de Enfermedad Infecciosa/estadística & datos numéricos , Complicaciones Infecciosas del Embarazo , Adulto , Fiebre Chikungunya/diagnóstico , Fiebre Chikungunya/epidemiología , Fiebre Chikungunya/fisiopatología , Fiebre Chikungunya/transmisión , Virus Chikungunya/aislamiento & purificación , Parto Obstétrico/efectos adversos , Parto Obstétrico/métodos , Parto Obstétrico/estadística & datos numéricos , Brotes de Enfermedades/estadística & datos numéricos , Femenino , Sufrimiento Fetal/diagnóstico , Sufrimiento Fetal/etiología , Grenada/epidemiología , Humanos , Recién Nacido , Embarazo , Complicaciones Infecciosas del Embarazo/diagnóstico , Complicaciones Infecciosas del Embarazo/epidemiología , Complicaciones Infecciosas del Embarazo/fisiopatología , Resultado del Embarazo/epidemiología , Pruebas Serológicas/métodos , Índice de Severidad de la EnfermedadRESUMEN
BACKGROUND: Zika virus (ZIKV) is a mosquito-borne virus that is also transmitted sexually; however, the epidemiological relevance of ZIKV sexual transmission in endemic regions is unclear. METHODS: We performed a household-based serosurvey in Northeast Brazil to evaluate the differential exposure to ZIKV and chikungunya virus (CHIKV) among households. Individuals who participated in our previous arboviral disease cohort (indexes) were recontacted and enrolled, and their household members were newly enrolled. RESULTS: The relative risk of sexual partners being ZIKV-seropositive when living with a ZIKV-seropositive index participant was significantly higher, whereas this was not observed among nonsexual partners of the index. For CHIKV, both sexual and nonsexual partner household members living with a CHIKV-seropositive index had a significantly higher risk of being seropositive. In the nonindex-based dyadic and generalized linear mixed model analyses, the odds of sexual dyads having a concordant ZIKV plaque reduction neutralization test result was significantly higher. We have also analyzed retrospective clinical data according to the participants' exposure to ZIKV and CHIKV. CONCLUSIONS: Our data suggest that ZIKV sexual transmission may be a key factor for the high ZIKV seroprevalence among households in endemic areas and raises important questions about differential disease from the 2 modes of transmission.
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Parejas Sexuales , Enfermedades Virales de Transmisión Sexual/epidemiología , Infección por el Virus Zika/epidemiología , Infección por el Virus Zika/transmisión , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Anticuerpos Antivirales/sangre , Brasil/epidemiología , Fiebre Chikungunya/epidemiología , Fiebre Chikungunya/transmisión , Virus Chikungunya/inmunología , Niño , Preescolar , Composición Familiar , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Riesgo , Estudios Seroepidemiológicos , Conducta Sexual , Enfermedades Virales de Transmisión Sexual/transmisión , Adulto Joven , Virus Zika/inmunologíaRESUMEN
Chikungunya virus (CHIKV) is a reemerging and rapidly spreading pathogen transmitted by mosquitoes. The emergence of new epidemic variants of the virus is associated with genetic evolutionary traits, including duplication of repeated RNA elements in the 3' untranslated region (UTR) that seemingly favor transmission by mosquitoes. The transmission potential of a given variant results from a complex interplay between virus populations and anatomical tissue barriers in the mosquito. Here, we used the wild-type CHIKV Caribbean strain and an engineered mutant harboring a deletion in the 3' UTR to dissect the interactions of virus variants with the anatomical barriers that impede transmission during the replication cycle of the virus in Aedes mosquitoes. Compared to the 3'-UTR mutant, we observed that the wild-type virus had a short extrinsic incubation period (EIP) after an infectious blood meal and was expectorated into mosquito saliva much more efficiently. We found that high viral titers in the midgut are not sufficient to escape the midgut escape barrier. Rather, viral replication kinetics play a crucial role in determining midgut escape and the transmission ability of CHIKV. Finally, competition tests in mosquitoes coinfected with wild-type and mutant viruses revealed that both viruses successfully colonized the midgut, but wild-type viruses effectively displaced mutant viruses during systemic infection due to their greater efficiency of escaping from the midgut into secondary tissues. Overall, our results uncover a link between CHIKV replication kinetics and the effect of bottlenecks on population diversity, as slowly replicating variants are less able to overcome the midgut escape barrier.IMPORTANCE It is well established that selective pressures in mosquito vectors impose population bottlenecks for arboviruses. Here, we used a CHIKV Caribbean lineage mutant carrying a deletion in the 3' UTR to study host-virus interactions in vivo in the epidemic mosquito vector Aedes aegypti We found that the mutant virus had a delayed replication rate in mosquitoes, which lengthened the extrinsic incubation period (EIP) and reduced fitness relative to the wild-type virus. As a result, the mutant virus displayed a reduced capacity to cross anatomical barriers during the infection cycle in mosquitoes, thus reducing the virus transmission rate. Our findings show how selective pressures act on CHIKV noncoding regions to select variants with shorter EIPs that are preferentially transmitted by the mosquito vector.
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Aedes/virología , Fiebre Chikungunya/transmisión , Virus Chikungunya/patogenicidad , Tracto Gastrointestinal/virología , Interacciones Huésped-Patógeno , Mosquitos Vectores/virología , Replicación Viral , Animales , Virus Chikungunya/genética , Femenino , Humanos , Mutación , Carga ViralRESUMEN
BACKGROUND: Like many countries from the Americas, Cuba is threatened by Aedes aegypti-associated arboviruses such as dengue (DENV), Zika (ZIKV), and chikungunya (CHIKV) viruses. Curiously, when CHIKV was actively circulating in the region in 2013-2014, no autochthonous transmission of this virus was detected in Havana, Cuba, despite the importation of chikungunya cases into this city. To investigate if the transmission ability of local mosquito populations could explain this epidemiological scenario, we evaluated for the first time the vector competence of two Ae. aegypti populations (Pasteur and Párraga) collected from Havana for dengue virus type 1 (DENV-1), CHIKV, and ZIKV. METHODOLOGY/PRINCIPAL FINDINGS: Mosquito populations were fed separately using blood containing ZIKV, DENV-1, or CHIKV. Infection, dissemination, and transmission rates, were estimated at 3 (exclusively for CHIKV), 7, and 14 days post exposure (dpe) for each Ae. aegypti population-virus combination. Both mosquito populations were susceptible to DENV-1 and ZIKV, with viral infection and dissemination rates ranging from 24-97% and 6-67% respectively. In addition, CHIKV disseminated in both populations and was subsequently transmitted. Transmission rates were low (<30%) regardless of the mosquito population/virus combination and no ZIKV was detected in saliva of females from the Pasteur population at any dpe. CONCLUSIONS/SIGNIFICANCE: Our study demonstrated the ability of Ae. aegypti from Cuba to transmit DENV, ZIKV, and CHIKV. These results, along with the widespread distribution and high abundance of this species in the urban settings throughout the island, highlight the importance of Ae. aegypti control and arbovirus surveillance to prevent future outbreaks.