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1.
Medicine (Baltimore) ; 100(17): e25695, 2021 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-33907147

RESUMO

RATIONALE: The chikungunya virus (CHIKV) was first isolated in a Tanzanian epidemic area between 1952 and 1953. The best description of the CHIKV transmission during pregnancy can be found in a well-documented epidemic in 2005, in the "La Reunion" island, a French territory located in the Indian Ocean, in which about one-third of the population was infected. Reports of arbovirus infections in pregnancy are increasing over time, but the spectrum of clinical findings remains an incognita among researchers, including CHIKV. PATIENT CONCERNS: In this report, it was possible to verify 2 cases exposed to CHIKV during foetal period and the possible implications of the infection on gestational structures and exposed children after the birth. DIAGNOSIS: In both cases, the mothers were positive by laboratory tests in serologic analysis for CHIKV, as ezyme-linked immunossorbent assay (ELISA), plaque reduction neutralisation testing (PRNT) and immunofluorescence (IF); but there were no positive tests in quantitative polymerase chain reaction (qPCR) for mothers or children. INTERVENTIONS: The exposed children were followed up in a paediatrics clinic in order not only to provide the medical assistance, but also to verify child development and the possible implications and neurocognitive changes caused by gestational infection. OUTCOMES: There were neurological and developmental changes in one of the children followed up on an outpatient basis. There was an improvement in the neurological situation and symptoms only 3 years and 1 month after birth. LESSONS: Based on the cases presented, we can conclude that clinical symptoms of CHIKV maternal infection may occur late in new-borns and can affect their development.


Assuntos
Febre de Chikungunya , Vírus Chikungunya , Complicações Infecciosas na Gravidez , Efeitos Tardios da Exposição Pré-Natal , Transtornos Psicomotores , Tempo , Anticorpos Antivirais/sangue , Febre de Chikungunya/diagnóstico , Febre de Chikungunya/imunologia , Febre de Chikungunya/transmissão , Vírus Chikungunya/imunologia , Vírus Chikungunya/isolamento & purificação , Desenvolvimento Infantil , Pré-Escolar , Continuidade da Assistência ao Paciente , Feminino , Humanos , Recém-Nascido , Transmissão Vertical de Doença Infecciosa , Testes de Estado Mental e Demência , Gravidez , Complicações Infecciosas na Gravidez/diagnóstico , Complicações Infecciosas na Gravidez/imunologia , Efeitos Tardios da Exposição Pré-Natal/diagnóstico , Efeitos Tardios da Exposição Pré-Natal/fisiopatologia , Transtornos Psicomotores/diagnóstico , Transtornos Psicomotores/etiologia , Testes Sorológicos/métodos
2.
Arch Virol ; 166(5): 1455-1462, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33704558

RESUMO

During the dengue epidemic in Yunnan Province, China, during 2019, a concurrent outbreak of chikungunya occurred in the city of Ruili, which is located in the southwest of the province, adjacent to Myanmar. As part of this outbreak, three neonatal cases of infection with indigenous chikungunya virus from mother-to-child (vertical) transmission were observed. Isolates of chikungunya virus were obtained from 37 serum samples of patients with chikungunya during this outbreak, and a phylogenetic analysis of these isolates revealed that they belong to the Indian Ocean subclade of the East/Central/South African genotype. The E1 genes of these viruses did not harbor the A226V mutation.


Assuntos
Febre de Chikungunya/virologia , Vírus Chikungunya/isolamento & purificação , Doenças Transmissíveis Emergentes/virologia , Transmissão Vertical de Doença Infecciosa , Febre de Chikungunya/epidemiologia , Febre de Chikungunya/transmissão , Vírus Chikungunya/classificação , Vírus Chikungunya/genética , China/epidemiologia , Doenças Transmissíveis Emergentes/epidemiologia , Doenças Transmissíveis Emergentes/transmissão , Surtos de Doenças , Feminino , Genoma Viral/genética , Genótipo , Humanos , Masculino , Mutação , Filogenia , RNA Viral/genética , Proteínas Virais/genética
3.
Mol Biol Rep ; 48(2): 1967-1975, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33523371

RESUMO

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.


Assuntos
Febre de Chikungunya/epidemiologia , Vírus Chikungunya/genética , Adolescente , Adulto , Febre de Chikungunya/transmissão , Febre de Chikungunya/virologia , Criança , Pré-Escolar , Bases de Dados Genéticas , Surtos de Doenças , Feminino , Genótipo , Humanos , Masculino , México , Pessoa de Meia-Idade , Filogenia , Estudos Retrospectivos , Análise de Sequência de DNA
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
6.
Artigo em Inglês | MEDLINE | ID: mdl-32932665

RESUMO

The risk of increasing dengue (DEN) and chikungunya (CHIK) epidemics impacts 240 million people, health systems, and the economy in the Hindu Kush Himalayan (HKH) region. The aim of this systematic review is to monitor trends in the distribution and spread of DEN/CHIK over time and geographically for future reliable vector and disease control in the HKH region. We conducted a systematic review of the literature on the spatiotemporal distribution of DEN/CHIK in HKH published up to 23 January 2020, following Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. In total, we found 61 articles that focused on the spatial and temporal distribution of 72,715 DEN and 2334 CHIK cases in the HKH region from 1951 to 2020. DEN incidence occurs in seven HKH countries, i.e., India, Nepal, Bhutan, Pakistan, Bangladesh, Afghanistan, and Myanmar, and CHIK occurs in four HKH countries, i.e., India, Nepal, Bhutan, and Myanmar, out of eight HKH countries. DEN is highly seasonal and starts with the onset of the monsoon (July in India and June in Nepal) and with the onset of spring (May in Bhutan) and peaks in the postmonsoon season (September to November). This current trend of increasing numbers of both diseases in many countries of the HKH region requires coordination of response efforts to prevent and control the future expansion of those vector-borne diseases to nonendemic areas, across national borders.


Assuntos
Febre de Chikungunya , Dengue , Febre de Chikungunya/epidemiologia , Febre de Chikungunya/transmissão , Vírus Chikungunya , Dengue/epidemiologia , Dengue/transmissão , Vírus da Dengue , Humanos , Saúde Pública , Análise Espaço-Temporal
7.
Rev Prat ; 70(3): 336-340, 2020 Mar.
Artigo em Francês | MEDLINE | ID: mdl-32877073

RESUMO

Chikungunya. Chikungunya is a cosmopolitan arbovirosis transmitted by a mosquito of the genus Aedes. It is characterized by the possible persistence of musculoskeletal symptoms more than three months after infection. After inoculation by an infected mosquito and incubation for three days, the infection is symptomatic in 75-95% of cases. There are three stages. The acute stage is characterized by the sudden onset of high fever associated with incapacitating distal polyarthralgia. Atypical, sometimes severe, manifestations are possible: neurological, digestive, cardiac, hepatic, dermatological, hematological, pulmonary and renal. These atypical forms are most often observed at extreme ages and in people with chronic diseases. The post-acute stage (60-80% of cases, from the fourth week to the end of the third month) is characterized by persistent and polymorphic musculoskeletal manifestations. During the chronic stage (50% of cases from the fourth month onwards) two entities can be distinguished: chronic inflammatory rheumatism and musculoskeletal disorders. Management is symptomatic. It is based on a precise semiological analysis, attentive listening to the patient and a multidisciplinary approach.


Assuntos
Aedes , Artrite Reumatoide , Febre de Chikungunya , Vírus Chikungunya , Animais , Febre de Chikungunya/complicações , Febre de Chikungunya/diagnóstico , Febre de Chikungunya/transmissão , Doença Crônica , Humanos
8.
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
9.
Am J Trop Med Hyg ; 103(4): 1660-1669, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32700661

RESUMO

Chikungunya fever is a viral mosquito-borne, acute febrile illness associated with rash, joint pain, and occasionally prolonged polyarthritis. Chikungunya outbreaks have been reported worldwide including many provinces of Thailand. Although chikungunya virus (CHIKV) occurs in Thailand, details on its epidemiology are lacking compared with dengue, a common mosquito-borne disease in the country. Therefore, study on CHIKV and its epidemiology in both humans and mosquitoes is required to better understand its importance clinically and dynamics in community settings. So a prospective examination of virus circulation in human and mosquito populations in northeastern Thailand using serological and molecular methods, including the genetic characterization of the virus, was undertaken. The study was conducted among febrile patients in eight district hospitals in northeastern Thailand from June 2016 to October 2017. Using real-time PCR on the conserved region of nonstructural protein 1 gene, CHIKV was detected in eight (4.9%) of 161 plasma samples. Only one strain yielded a sequence of sufficient size allowing for phylogenetic analysis. In addition, anti-CHIKV IgM and IgG were detected in six (3.7%) and 17 (10.6%) patient plasma samples. The single sequenced sample belonged to the East/Central/South Africa (ECSA) genotype and was phylogenetically similar to the Indian Ocean sub-lineage. Adult Aedes mosquitoes were collected indoors and within a 100-m radius from the index case house and four neighboring houses. CHIKV was detected in two of 70 (2.9%) female Aedes aegypti mosquito pools. This study clearly demonstrated the presence and local transmission of the ECSA genotype of CHIKV in the northeastern region of Thailand.


Assuntos
Aedes/virologia , Anticorpos Antivirais/sangue , Febre de Chikungunya/epidemiologia , Vírus Chikungunya/imunologia , Surtos de Doenças , Mosquitos Vetores/virologia , Adolescente , Adulto , Idoso , Animais , Febre de Chikungunya/transmissão , Febre de Chikungunya/virologia , Vírus Chikungunya/genética , Vírus Chikungunya/isolamento & purificação , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Filogenia , Estudos Prospectivos , Tailândia/epidemiologia , Adulto Jovem
10.
PLoS Negl Trop Dis ; 14(6): e0008362, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32559197

RESUMO

Arboviruses are among the most important emerging pathogens due to their increasing public health impact. In Kenya, continued population growth and associated urbanization are conducive to vector spread in both urban and rural environments, yet mechanisms of viral amplification in vector populations is often overlooked when assessing risks for outbreaks. Thus, the characterization of local arbovirus circulation in mosquito populations is imperative to better inform risk assessments and vector control practices. Aedes species mosquitoes were captured at varying stages of their life cycle during different seasons between January 2014 and May 2016 at four distinct sites in Kenya, and tested for chikungunya (CHIKV), dengue (DENV) and Zika (ZIKV) viruses by RT-PCR. CHIKV was detected in 45 (5.9%) and DENV in 3 (0.4%) mosquito pools. No ZIKV was detected. Significant regional variation in prevalence was observed, with greater frequency of CHIKV on the coast. DENV was detected exclusively on the coast. Both viruses were detected in immature mosquitoes of both sexes, providing evidence of transovarial transmission of these arboviruses in local mosquitoes. This phenomenon may be driving underlying viral maintenance that may largely contribute to periodic re-emergence among humans in Kenya.


Assuntos
Febre de Chikungunya/transmissão , Vírus Chikungunya/isolamento & purificação , Culicidae/virologia , Vírus da Dengue/isolamento & purificação , Dengue/transmissão , Aedes/fisiologia , Aedes/virologia , Animais , Arbovirus , Febre de Chikungunya/epidemiologia , Febre de Chikungunya/virologia , Culicidae/fisiologia , Dengue/epidemiologia , Dengue/virologia , Feminino , Humanos , Quênia/epidemiologia , Estágios do Ciclo de Vida , Masculino , Zika virus , Infecção por Zika virus/virologia
12.
PLoS Negl Trop Dis ; 14(6): e0008159, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32525957

RESUMO

KEY RESULTS: Both outbreaks started in small towns, but cases were also detected in nearby larger cities where transmission was limited to small clusters. The time spans between the first and the last symptom onsets were similar between the 2 outbreaks, and the delay from the symptom onset of the index case and the first case notified was considerable. Comparable infection and transmission rates were observed in laboratory. The basic reproductive number (R0) was estimated in the range of 1.8-6 (2007) and 1.5-2.6 (2017). Clinical characteristics were similar between outbreaks, and no acute complications were reported, though a higher frequency of ocular symptoms, myalgia, and rash was observed in 2017. Very little is known about the immune mediator profile of CHIKV-infected patients during the 2 outbreaks. Regarding public health responses, after the 2007 outbreak, the Italian Ministry of Health developed national guidelines to implement surveillance and good practices to prevent and control autochthonous transmission. However, only a few regional authorities implemented it, and the perception of outbreak risk and knowledge of clinical symptoms and transmission dynamics by general practitioners remained low. MAJOR CONCLUSIONS: Efforts should be devoted to developing suitable procedures for early detection of virus circulation in the population, possibly through the analysis of medical records in near real time. Increasing the awareness of CHIKV of general practitioners and public health officials through tailored education may be effective, especially in small coastal towns where the outbreak risk may be higher. A key element is also the shift of citizen awareness from considering Aedes mosquitoes not only as a nuisance problem but also as a public health one. We advocate the need of strengthening the surveillance and of promoting the active participation of the communities to prevent and contain future outbreaks.


Assuntos
Febre de Chikungunya/epidemiologia , Febre de Chikungunya/transmissão , Surtos de Doenças , Transmissão de Doença Infecciosa/prevenção & controle , Doenças Transmitidas por Vetores/epidemiologia , Doenças Transmitidas por Vetores/transmissão , Animais , Número Básico de Reprodução , Febre de Chikungunya/patologia , Febre de Chikungunya/virologia , Controle de Doenças Transmissíveis/organização & administração , Monitoramento Epidemiológico , Educação em Saúde/organização & administração , Política de Saúde , Humanos , Itália/epidemiologia , Resultado do Tratamento , Doenças Transmitidas por Vetores/patologia , Doenças Transmitidas por Vetores/virologia
13.
Am J Trop Med Hyg ; 103(2): 869-875, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32431284

RESUMO

Chikungunya virus (CHIKV) and Zika virus (ZIKV) are arthropod-borne viruses transmitted mainly by Aedes aegypti mosquitoes. These viruses have become endemic in large parts of North, Central, and South America. Arboviruses persistently infect mosquitoes throughout their life span and become infectious (i.e., expectorate infectious virus in saliva) after a period of time called the extrinsic incubation period (EIP). The duration of this infectiousness, however, is not well characterized. This is an important shortcoming because many epidemiological models assume that mosquitoes continue to be infectious for the duration of their life span. To define the duration of infectiousness for CHIKV and ZIKV, mosquitoes were infected orally with these viruses. Every 2 days, legs/wings, midguts, salivary glands, and saliva were collected from 30 to 60 mosquitoes and viral load measured. In CHIKV-infected mosquitoes, infectious virus in saliva peaked early (2-4 dpi), and then decreased rapidly and was rarely observed after 10 dpi. Viral RNA in infected tissues also decreased after the initial peak (4-8 dpi) but did so much less drastically. In ZIKV-infected mosquitoes, the infectious virus in saliva peaked at 12-14 dpi and dropped off only slightly after 14 dpi. In infected tissues, viral RNA increased early during infection, and then plateaued after 6-10 days. Our findings suggest that significant variation exists in the duration of the infectious period for arboviruses that is in part influenced by virus clearance from expectorated saliva.


Assuntos
Aedes/virologia , Vírus Chikungunya/fisiologia , Intestinos/virologia , Saliva/virologia , Glândulas Salivares/virologia , Replicação Viral/fisiologia , Zika virus/fisiologia , Animais , Febre de Chikungunya/transmissão , Extremidades/virologia , Período de Incubação de Doenças Infecciosas , Mosquitos Vetores/virologia , Asas de Animais/virologia , Infecção por Zika virus/transmissão
14.
PLoS Negl Trop Dis ; 14(5): e0008320, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32392224

RESUMO

BACKGROUND: The global spread of Aedes albopictus has exposed new geographical areas to the risk of dengue and chikungunya virus transmission. Several autochthonous transmission events have occurred in recent decades in Southern Europe and many indicators suggest that it will become more frequent in this region in the future. Environmental, socioeconomic and climatic factors are generally considered to trigger the emergence of these viruses. Accordingly, a greater knowledge of the determinants of this emergence in a European context is necessary to develop adapted surveillance and control strategies, and public health interventions. METHODOLOGY/PRINCIPAL FINDINGS: Using French surveillance data collected from between 2010 and 2018 in areas of Southern France where Ae. albopictus is already established, we assessed factors associated with the autochthonous transmission of dengue and chikungunya. Cases leading to autochthonous transmission were compared with those without subsequent transmission using binomial regression. We identified a long reporting delay (≥ 21 days) of imported cases to local health authorities as the main driver for autochthonous transmission of dengue and chikungunya in Southern France. The presence of wooded areas around the cases' place of residence and the accumulation of heat during the season also increased the risk of autochthonous arbovirus transmission. CONCLUSIONS: Our findings could inform policy-makers when developing strategies to the emerging threats of dengue and chikungunya in Southern Europe and can be extrapolated in this area to other viruses such as Zika and yellow fever, which share the same vector. Furthermore, our results allow a more accurate characterization of the environments most at risk, and highlight the importance of implementing surveillance systems which ensure the timely reporting and of imported cases and swift interventions.


Assuntos
Aedes/crescimento & desenvolvimento , Febre de Chikungunya/transmissão , Dengue/transmissão , Transmissão de Doença Infecciosa , Mosquitos Vetores/crescimento & desenvolvimento , Animais , Febre de Chikungunya/epidemiologia , Dengue/epidemiologia , Feminino , França/epidemiologia , Humanos , Masculino
15.
PLoS Negl Trop Dis ; 14(5): e0008250, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32401756

RESUMO

BACKGROUND: The French overseas Territory of the Wallis and Futuna Islands has been affected by several dengue epidemics. Aedes polynesiensis is the main mosquito vector described in this territory. Other Aedes species have been reported, but recent entomological data are missing to infer the presence of other potential arbovirus vectors and to assess the entomological risk factors for transmission of arboviral diseases. METHODOLOGY/ PRINCIPAL FINDINGS: An entomological prospective study was conducted on the three main islands of the territory to determine the presence and distribution of Aedes spp. Larvae, pupae and adult mosquitoes were collected from 54 sampling points in different environments, with a final sampling of 3747 immature stages and 606 adults. The main identified breeding sites were described. Ae. polynesiensis was found in every sampled site in peridomestic and wild habitats. Ae. aegypti was only found on the island of Wallis in peridomestic environments with a limited distribution. Two other Aedes species endemic to the Pacific were recorded, Aedes oceanicus and Aedes futunae. To evaluate the ability of local Ae. polynesiensis to transmit the chikungunya virus (CHIKV), two field populations were analyzed for vector competence using experimental oral exposure of females to CHIKV and infection, dissemination and transmission assays. Results showed that both populations of Ae. polynesiensis were competent for CHIKV (30% at 7 days post-infection). CONCLUSIONS/SIGNIFICANCE: This study showed the ubiquitous distribution and abundance of Ae. polynesiensis on the three islands and demonstrated that local populations were able to transmit CHIKV. Combined with the presence and expansion of Ae. aegypti on the main island of Wallis, these data highlight the risk of transmission of arboviral diseases in the territory of Wallis and Futuna and provide relevant information for entomological surveillance and vector control programs.


Assuntos
Aedes/crescimento & desenvolvimento , Febre de Chikungunya/transmissão , Transmissão de Doença Infecciosa , Ecossistema , Mosquitos Vetores/crescimento & desenvolvimento , Animais , Feminino , Polinésia , Estudos Prospectivos , Medição de Risco , Inquéritos e Questionários
16.
PLoS Negl Trop Dis ; 14(4): e0008219, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32298261

RESUMO

Aedes aegypti is the primary vector of dengue, chikungunya, Zika, and urban yellow fever. Insecticides are often the most effective tools to rapidly decrease the density of vector populations, especially during arbovirus disease outbreaks. However, the intense use of insecticides, particularly pyrethroids, has selected for resistant mosquito populations worldwide. Mutations in the voltage gated sodium channel (NaV) are among the principal mechanisms of resistance to pyrethroids and DDT, also known as "knockdown resistance," kdr. Here we report studies on the origin and dispersion of kdr haplotypes in samples of Ae. aegypti from its worldwide distribution. We amplified the IIS6 and IIIS6 NaV segments from pools of Ae. aegypti populations from 15 countries, in South and North America, Africa, Asia, Pacific, and Australia. The amplicons were barcoded and sequenced using NGS Ion Torrent. Output data were filtered and analyzed using the bioinformatic pipeline Seekdeep to determine frequencies of the IIS6 and IIIS6 haplotypes per population. Phylogenetic relationships among the haplotypes were used to infer whether the kdr mutations have a single or multiple origin. We found 26 and 18 haplotypes, respectively for the IIS6 and IIIS6 segments, among which were the known kdr mutations 989P, 1011M, 1016I and 1016G (IIS6), 1520I, and 1534C (IIIS6). The highest diversity of haplotypes was found in African samples. Kdr mutations 1011M and 1016I were found only in American and African populations, 989P + 1016G and 1520I + 1534C in Asia, while 1534C was present in samples from all continents, except Australia. Based primarily on the intron sequence, IIS6 haplotypes were subdivided into two well-defined clades (A and B). Subsequent phasing of the IIS6 + IIIS6 haplotypes indicates two distinct origins for the 1534C kdr mutation. These results provide evidence of kdr mutations arising de novo at specific locations within the Ae. aegypti geographic distribution. In addition, our results suggest that the 1534C kdr mutation had at least two independent origins. We can thus conclude that insecticide selection pressure with DDT and more recently with pyrethroids is selecting for independent convergent mutations in NaV.


Assuntos
Aedes/efeitos dos fármacos , Aedes/genética , Genes de Insetos , Resistência a Inseticidas/genética , Mutação , Aedes/virologia , África , Alelos , Animais , Ásia , Austrália , Febre de Chikungunya/prevenção & controle , Febre de Chikungunya/transmissão , DNA/genética , Dengue/prevenção & controle , Dengue/transmissão , Frequência do Gene , Genótipo , Inseticidas , Mosquitos Vetores/genética , Mosquitos Vetores/virologia , América do Norte , Piretrinas , Febre Amarela/prevenção & controle , Febre Amarela/transmissão , Infecção por Zika virus/prevenção & controle , Infecção por Zika virus/transmissão
17.
Am J Trop Med Hyg ; 103(1): 149-156, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32342853

RESUMO

Dengue fever and other febrile mosquito-borne diseases place considerable health and economic burdens on small island nations in the Caribbean. Here, we used two methods of cluster detection to find potential hotspots of transmission of dengue and chikungunya in Barbados, and to assess the impact of input surveillance data and methodology on observed patterns of risk. Using Moran's I and spatial scan statistics, we analyzed the geospatial and temporal distribution of disease cases and rates across Barbados for dengue fever in 2013-2016, and a chikungunya outbreak in 2014. During years with high numbers of dengue cases, hotspots for cases were found with Moran's I in the south and central regions in 2013 and 2016, respectively. Using smoothed disease rates, clustering was detected in all years for dengue. Hotspots suggesting higher rates were not detected via spatial scan statistics, but coldspots suggesting lower than expected rates of disease activity were found in southwestern Barbados during high case years of dengue. No significant spatiotemporal structure was found in cases during the chikungunya outbreak. Spatial analysis of surveillance data is useful in identifying outbreak hotspots, potentially complementing existing early warning systems. We caution that these methods should be used in a manner appropriate to available data and reflecting explicit public health goals-managing for overall case numbers or targeting anomalous rates for further investigation.


Assuntos
Febre de Chikungunya/epidemiologia , Vírus Chikungunya/patogenicidade , Vírus da Dengue/patogenicidade , Dengue/epidemiologia , Surtos de Doenças , Análise Espaço-Temporal , Aedes/virologia , Animais , Barbados/epidemiologia , Febre de Chikungunya/transmissão , Febre de Chikungunya/virologia , Vírus Chikungunya/fisiologia , Análise por Conglomerados , Dengue/transmissão , Dengue/virologia , Vírus da Dengue/fisiologia , Doenças Endêmicas/estatística & dados numéricos , Monitoramento Epidemiológico , Humanos , Incidência , Mosquitos Vetores/virologia , Saúde Pública , Risco
18.
Sci Rep ; 10(1): 6803, 2020 04 22.
Artigo em Inglês | MEDLINE | ID: mdl-32321946

RESUMO

Aedes aegypti is the main vector of arboviral diseases such as dengue, chikungunya and Zika. A key feature for disease transmission modeling and vector control planning is adult mosquito dispersal. We studied Ae aegypti adult dispersal by conducting a mark-capture study of naturally occurring Ae. aegypti from discarded containers found along a canal that divided two residential communities in Donna, Texas, USA. Stable isotopes were used to enrich containers with either 13C or 15N. Adult mosquitoes were collected outdoors in the yards of households throughout the communities with BG Sentinel 2 traps during a 12-week period. Marked mosquito pools with stable isotopes were used to estimate the mean distance travelled using three different approaches (Net, Strip or Circular) and the probability of detecting an isotopically marked adult at different distances from the larval habitat of origin. We consistently observed, using the three approaches that male (Net: 220 m, Strip: 255 m, Circular: 250 m) Ae. aegypti dispersed further in comparison to gravid (Net: 135 m, Strip: 176 m, Circular: 189 m) and unfed females (Net: 192 m, Strip: 213 m, Circular: 198 m). We also observed that marked male capture probability slightly increased with distance, while, for both unfed and gravid females, such probability decreased with distance. Using a unique study design documenting adult dispersal from natural larval habitat, our results suggest that Ae. aegypti adults disperse longer distances than previously reported. These results may help guide local vector control authorities in their fight against Ae. aegypti and the diseases it transmits, suggesting coverage of 200 m for the use of insecticides and innovative vector control tools.


Assuntos
Isótopos de Carbono/metabolismo , Ecossistema , Meio Ambiente , Controle de Mosquitos/métodos , Isótopos de Nitrogênio/metabolismo , Algoritmos , Animais , Febre de Chikungunya/prevenção & controle , Febre de Chikungunya/transmissão , Febre de Chikungunya/virologia , Dengue/prevenção & controle , Dengue/transmissão , Dengue/virologia , Feminino , Humanos , Inseticidas/farmacologia , Masculino , Modelos Teóricos , Controle de Mosquitos/instrumentação , Mosquitos Vetores/efeitos dos fármacos , Mosquitos Vetores/metabolismo , Mosquitos Vetores/virologia , Texas , Infecção por Zika virus/prevenção & controle , Infecção por Zika virus/transmissão , Infecção por Zika virus/virologia
19.
BMC Evol Biol ; 20(1): 31, 2020 02 19.
Artigo em Inglês | MEDLINE | ID: mdl-32075576

RESUMO

BACKGROUND: In recent years, Ecuador and other South American countries have experienced an increase in arboviral diseases. A rise in dengue infections was followed by introductions of chikungunya and Zika, two viruses never before seen in many of these areas. Furthermore, the latest socioeconomic and political instability in Venezuela and the mass migration of its population into the neighboring countries has given rise to concerns of infectious disease spillover and escalation of arboviral spread in the region. RESULTS: We performed phylogeographic analyses of dengue (DENV) and chikungunya (CHIKV) virus genomes sampled from a surveillance site in Ecuador in 2014-2015, along with genomes from the surrounding countries. Our results revealed at least two introductions of DENV, in 2011 and late 2013, that initially originated from Venezuela and/or Colombia. The introductions were subsequent to increases in the influx of Venezuelan and Colombian citizens into Ecuador, which in 2013 were 343% and 214% higher than in 2009, respectively. However, we show that Venezuela has historically been an important source of DENV dispersal in this region, even before the massive exodus of its population, suggesting already established paths of viral distribution. Like DENV, CHIKV was introduced into Ecuador at multiple time points in 2013-2014, but unlike DENV, these introductions were associated with the Caribbean. Our findings indicated no direct CHIKV connection between Ecuador, Colombia, and Venezuela as of 2015, suggesting that CHIKV was, at this point, not following the paths of DENV spread. CONCLUSION: Our results reveal that Ecuador is vulnerable to arbovirus import from many geographic locations, emphasizing the need of continued surveillance and more diversified prevention strategies. Importantly, increase in human movement along established paths of viral dissemination, combined with regional outbreaks and epidemics, may facilitate viral spread and lead to novel virus introductions. Thus, strengthening infectious disease surveillance and control along migration routes and improving access to healthcare for the vulnerable populations is of utmost importance.


Assuntos
Febre de Chikungunya/epidemiologia , Vírus Chikungunya/classificação , Vírus Chikungunya/genética , Vírus da Dengue/classificação , Vírus da Dengue/genética , Dengue/epidemiologia , Emigração e Imigração/estatística & dados numéricos , Febre de Chikungunya/transmissão , Febre de Chikungunya/virologia , Vírus Chikungunya/isolamento & purificação , Colômbia/epidemiologia , Dengue/transmissão , Dengue/virologia , Vírus da Dengue/isolamento & purificação , Surtos de Doenças , Equador/epidemiologia , Emigração e Imigração/tendências , Genoma Viral , Genótipo , Humanos , Mutação de Sentido Incorreto/fisiologia , Fenótipo , Filogeografia , Análise de Sequência de DNA , América do Sul/epidemiologia , Venezuela/epidemiologia , Zika virus/isolamento & purificação , Infecção por Zika virus/epidemiologia , Infecção por Zika virus/transmissão , Infecção por Zika virus/virologia
20.
Epidemiol Infect ; 148: e63, 2020 02 19.
Artigo em Inglês | MEDLINE | ID: mdl-32070451

RESUMO

Chikungunya virus (CHIKV) is a re-emerging pathogen of global importance. We attempted to gain an insight into the organisation, distribution and mutational load of the virus strains reported from different parts of the world. We describe transmission dynamics and genetic characterisation of CHIKV across the globe during the last 65 years from 1952 to 2017. The evolutionary pattern of CHIKV was analysed using the E1 protein gene through phylogenetic, Bayesian and Network methods with a dataset of 265 sequences from various countries. The time to most recent common ancestor of the virus was estimated to be 491 years ago with an evolutionary rate of 2.78 × 10-4 substitutions/site/year. Genetic characterisation of CHIKV strains was carried out in terms of variable sites, selection pressure and epitope mapping. The neutral selection pressure on the E1 gene of the virus suggested a stochastic process of evolution. We identified six potential epitope peptides in the E1 protein showing substantial interaction with human MHC-I and MHC-II alleles. The present study augments global epidemiological and population dynamics of CHIKV warranting undertaking of appropriate control measures. The identification of epitopic peptides can be useful in the development of epitope-based vaccine strategies against this re-emerging viral pathogen.


Assuntos
Febre de Chikungunya , Vírus Chikungunya , Epidemias , Febre de Chikungunya/epidemiologia , Febre de Chikungunya/história , Febre de Chikungunya/transmissão , Febre de Chikungunya/virologia , Vírus Chikungunya/classificação , Vírus Chikungunya/genética , Epitopos de Linfócito B/genética , Evolução Molecular , Saúde Global , História do Século XX , História do Século XXI , Humanos , Filogenia , Proteínas do Envelope Viral/genética
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