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2.
Emerg Microbes Infect ; 9(1): 67-77, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31894724

RESUMO

Rapid and significant range expansion of both Zika virus (ZIKV) and its Aedes vector species has resulted in ZIKV being declared a global health threat. Mean temperatures are projected to increase globally, likely resulting in alterations of the transmission potential of mosquito-borne pathogens. To understand the effect of diurnal temperature range on the vectorial capacity of Ae. aegypti and Ae. albopictus for ZIKV, longevity, blood-feeding and vector competence were assessed at two temperature regimes following feeding on infectious blood meals. Higher temperatures resulted in decreased longevity of Ae. aegypti [Log-rank test, χ2, df 35.66, 5, P < 0.001] and a decrease in blood-feeding rates of Ae. albopictus [Fisher's exact test, P < 0.001]. Temperature had a population and species-specific impact on ZIKV infection rates. Overall, Ae. albopictus reared at the lowest temperature regime demonstrated the highest vectorial capacity (0.53) and the highest transmission efficiency (57%). Increased temperature decreased vectorial capacity across groups yet more significant effects were measured with Ae. aegypti relative to Ae. albopictus. The results of this study suggest that future increases in temperature in the Americas could significantly impact vector competence, blood-feeding and longevity, and potentially decrease the overall vectorial capacity of Aedes mosquitoes in the Americas.


Assuntos
Aedes/virologia , Mudança Climática , Mosquitos Vetores/virologia , Infecção por Zika virus/transmissão , Aedes/classificação , Animais , Sangue , Comportamento Alimentar , Feminino , Florida , México , Mosquitos Vetores/fisiologia , New York , Temperatura Ambiente
3.
BMC Infect Dis ; 19(1): 1081, 2019 Dec 26.
Artigo em Inglês | MEDLINE | ID: mdl-31878895

RESUMO

BACKGROUND: The European Commission (EC) Horizon 2020 (H2020)-funded ZIKAlliance Consortium designed a multicentre study including pregnant women (PW), children (CH) and natural history (NH) cohorts. Clinical sites were selected over a wide geographic range within Latin America and the Caribbean, taking into account the dynamic course of the ZIKV epidemic. METHODS: Recruitment to the PW cohort will take place in antenatal care clinics. PW will be enrolled regardless of symptoms and followed over the course of pregnancy, approximately every 4 weeks. PW will be revisited at delivery (or after miscarriage/abortion) to assess birth outcomes, including microcephaly and other congenital abnormalities according to the evolving definition of congenital Zika syndrome (CZS). After birth, children will be followed for 2 years in the CH cohort. Follow-up visits are scheduled at ages 1-3, 4-6, 12, and 24 months to assess neurocognitive and developmental milestones. In addition, a NH cohort for the characterization of symptomatic rash/fever illness was designed, including follow-up to capture persisting health problems. Blood, urine, and other biological materials will be collected, and tested for ZIKV and other relevant arboviral diseases (dengue, chikungunya, yellow fever) using RT-PCR or serological methods. A virtual, decentralized biobank will be created. Reciprocal clinical monitoring has been established between partner sites. Substudies of ZIKV seroprevalence, transmission clustering, disabilities and health economics, viral kinetics, the potential role of antibody enhancement, and co-infections will be linked to the cohort studies. DISCUSSION: Results of these large cohort studies will provide better risk estimates for birth defects and other developmental abnormalities associated with ZIKV infection including possible co-factors for the variability of risk estimates between other countries and regions. Additional outcomes include incidence and transmission estimates of ZIKV during and after pregnancy, characterization of short and long-term clinical course following infection and viral kinetics of ZIKV. STUDY REGISTRATIONS: clinicaltrials.gov NCT03188731 (PW cohort), June 15, 2017; clinicaltrials.gov NCT03393286 (CH cohort), January 8, 2018; clinicaltrials.gov NCT03204409 (NH cohort), July 2, 2017.


Assuntos
Arbovirus/isolamento & purificação , Microcefalia/complicações , Complicações Infecciosas na Gravidez/epidemiologia , Infecção por Zika virus/epidemiologia , Zika virus/imunologia , Adulto , Arbovirus/genética , Região do Caribe/epidemiologia , Criança , Pré-Escolar , Estudos de Coortes , Coinfecção , Feminino , Seguimentos , Humanos , Lactente , América Latina/epidemiologia , Microcefalia/epidemiologia , Microcefalia/virologia , Gravidez , Complicações Infecciosas na Gravidez/virologia , Cuidado Pré-Natal , Estudos Prospectivos , Risco , Estudos Soroepidemiológicos , Zika virus/isolamento & purificação , Infecção por Zika virus/transmissão , Infecção por Zika virus/virologia
4.
PLoS Negl Trop Dis ; 13(12): e0007988, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31877132

RESUMO

BACKGROUND: Detecting and monitoring the transmission of arboviruses such as Zika virus (ZIKV), dengue virus, and chikungunya virus is critical for prevention and control activities. Previous work has compared the ability of different human-focused surveillance strategies to detect ZIKV transmission in U.S. counties where no known transmission had occurred, but whether virological surveillance in mosquitoes could represent an effective surveillance system is unclear. OBJECTIVES: We leveraged a unique set of data from human and virological surveillance in Ae. aegypti during the 2016 ZIKV epidemic in Caguas, Puerto Rico, to compare alternative strategies for detecting and monitoring ZIKV activity. METHODS: We developed a simulation model for mosquito and human surveillance strategies and simulated different transmission scenarios with varying infection rates and mosquito trap densities. We then calculated the expected weekly number of detected infections, the probability of detecting transmission, and the number of tests needed and compared the simulations with observed data from Caguas. RESULTS: In simulated high transmission scenarios (1 infection per 1,000 people per week), the models demonstrated that both approaches had estimated probabilities of detection of greater than 78%. In simulated low incidence scenarios, vector surveillance had higher sensitivity than human surveillance and sensitivity increased with more traps, more trapping effort, and testing. In contrast, the actual data from Caguas indicated that human virological surveillance was more sensitive than vector virological surveillance during periods of both high and low transmission. CONCLUSION: In scenarios where human surveillance is not possible or when transmission intensity is very low, virological surveillance in Ae. aegypti may be able to detect and monitor ZIKV epidemic activity. However, surveillance for humans seeking care for Zika-like symptoms likely provides an equivalent or more sensitive indicator of transmission intensity in most circumstances.


Assuntos
Aedes/virologia , Transmissão de Doença Infecciosa/prevenção & controle , Monitoramento Epidemiológico , Mosquitos Vetores/virologia , Infecção por Zika virus/prevenção & controle , Zika virus/isolamento & purificação , Animais , Simulação por Computador , Feminino , Incidência , Porto Rico/epidemiologia , Sensibilidade e Especificidade , Infecção por Zika virus/epidemiologia , Infecção por Zika virus/transmissão
5.
Braz J Med Biol Res ; 52(11): e8339, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31721902

RESUMO

A progressive increase in the circulation of arboviruses in tropical countries has been observed, accounting for 700,000 yearly deaths in the world. The main objective of this article was to identify the presence of Zika (ZIKV), dengue (DENV), and Chikungunya (CHIKV) viruses in immature stages of Aedes aegypti and Ae. albopictus. Household collections of immature phases of the vectors were carried out in the years 2015 and 2016. A total of 2902 dwellings were visited and the rate of infestation with larvae and pupae of Aedes mosquitoes was 283/1462 (19.4%) in March 2015 and 55/1440 (3.8%) in June 2015. In March 2015, 907 larvae/pupae were collected (583 or 64.3% of Ae. aegypti and 324 or 35.7% of Ae. albopictus) while in June 2015 there was a reduction in the number of immature forms found: 197 larvae/pupae (121 or 61.4% of Ae. aegypti and 76 or 38.6% of Ae. albopictus). This reduction was accompanied by a decrease in suspected human ZIKV cases from March to June 2015. The RT-qPCR performed in 18 pools identified that three (two of Ae. aegypti and one of Ae. albopictus) were positive for ZIKV, and none were positive for DENV or CHIKV. Our findings demonstrated that ZIKV was present in immature stages of insect vectors in the study region at least five months prior to the peak of ZIKV associated cases. Xenomonitoring of immature phases of the vectors may prove useful for predicting outbreaks.


Assuntos
Aedes/virologia , Vírus Chikungunya/isolamento & purificação , Vírus da Dengue/isolamento & purificação , Mosquitos Vetores/virologia , Zika virus/isolamento & purificação , Aedes/classificação , Animais , Humanos , Mosquitos Vetores/classificação , RNA Viral/análise , Reação em Cadeia da Polimerase em Tempo Real , Estações do Ano , Infecção por Zika virus/transmissão
6.
BMC Infect Dis ; 19(1): 963, 2019 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-31718580

RESUMO

BACKGROUND: Colombia was the second most affected country during the American Zika virus (ZIKV) epidemic, with over 109,000 reported cases. Despite the scale of the outbreak, limited genomic sequence data were available from Colombia. We sought to sequence additional samples and use genomic epidemiology to describe ZIKV dynamics in Colombia. METHODS: We sequenced ZIKV genomes directly from clinical diagnostic specimens and infected Aedes aegypti samples selected to cover the temporal and geographic breadth of the Colombian outbreak. We performed phylogeographic analysis of these genomes, along with other publicly-available ZIKV genomes from the Americas, to estimate the frequency and timing of ZIKV introductions to Colombia. RESULTS: We attempted PCR amplification on 184 samples; 19 samples amplified sufficiently to perform sequencing. Of these, 8 samples yielded sequences with at least 50% coverage. Our phylogeographic reconstruction indicates two separate introductions of ZIKV to Colombia, one of which was previously unrecognized. We find that ZIKV was first introduced to Colombia in February 2015 (95%CI: Jan 2015 - Apr 2015), corresponding to 5 to 8 months of cryptic ZIKV transmission prior to confirmation in September 2015. Despite the presence of multiple introductions, we find that the majority of Colombian ZIKV diversity descends from a single introduction. We find evidence for movement of ZIKV from Colombia into bordering countries, including Peru, Ecuador, Panama, and Venezuela. CONCLUSIONS: Similarly to genomic epidemiological studies of ZIKV dynamics in other countries, we find that ZIKV circulated cryptically in Colombia. More accurately dating when ZIKV was circulating refines our definition of the population at risk. Additionally, our finding that the majority of ZIKV transmission within Colombia was attributable to transmission between individuals, rather than repeated travel-related importations, indicates that improved detection and control might have succeeded in limiting the scale of the outbreak within Colombia.


Assuntos
Genoma Viral , Infecção por Zika virus/virologia , Zika virus/genética , Aedes/virologia , Animais , Colômbia/epidemiologia , Surtos de Doenças , Evolução Molecular , Variação Genética , Humanos , Filogenia , Filogeografia , Zika virus/classificação , Zika virus/isolamento & purificação , Infecção por Zika virus/epidemiologia , Infecção por Zika virus/transmissão
8.
Emerg Microbes Infect ; 8(1): 1668-1678, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31735122

RESUMO

Since its emergence in Yap Island in 2007, Zika virus (ZIKV) has affected all continents except Europe. Despite the hundreds of cases imported to European countries from ZIKV-infested regions, no local cases have been reported in localities where the ZIKV-competent mosquito Aedes albopictus is well established. Here we analysed the vector competence of European Aedes (aegypti and albopictus) mosquitoes to different genotypes of ZIKV. We demonstrate that Ae. albopictus from France was less susceptible to the Asian ZIKV than to the African ZIKV. Critically we show that effective crossing of anatomical barriers (midgut and salivary glands) after an infectious blood meal depends on a viral load threshold to trigger: (i) viral dissemination from the midgut to infect mosquito internal organs and (ii) viral transmission from the saliva to infect a vertebrate host. A viral load in body ≥4800 viral copies triggered dissemination and ≥12,000 viral copies set out transmission. Only 27.3% and 18.2% of Ae. albopictus Montpellier mosquitoes meet respectively these two criteria. Collectively, these compelling results stress the poor ability of Ae. albopictus to sustain a local transmission of ZIKV in Europe and provide a promising tool to evaluate the risk of ZIKV transmission in future outbreaks.


Assuntos
Aedes/fisiologia , Mosquitos Vetores/fisiologia , Infecção por Zika virus/transmissão , Zika virus/fisiologia , Aedes/genética , Aedes/virologia , Animais , Europa (Continente) , Feminino , Humanos , Mosquitos Vetores/genética , Mosquitos Vetores/virologia , Carga Viral , Zika virus/genética , Infecção por Zika virus/virologia
10.
PLoS Negl Trop Dis ; 13(10): e0007615, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31600206

RESUMO

BACKGROUND: The landscape of mosquito-borne disease risk has changed dramatically in recent decades, due to the emergence and reemergence of urban transmission cycles driven by invasive Aedes aegypti and Ae. albopictus. Insecticide resistance is already widespread in the yellow fever mosquito, Ae. Aegypti; is emerging in the Asian tiger mosquito Ae. Albopictus; and is now threatening the global fight against human arboviral diseases such as dengue, yellow fever, chikungunya, and Zika. Because the panel of insecticides available for public health is limited, it is of primary importance to preserve the efficacy of existing and upcoming active ingredients. Timely implementation of insecticide resistance management (IRM) is crucial to maintain the arsenal of effective public health insecticides and sustain arbovirus vector control. METHODOLOGY AND PRINCIPAL FINDINGS: This Review is one of a series being generated by the Worldwide Insecticide resistance Network (WIN) and aims at defining the principles and concepts underlying IRM, identifying the main factors affecting the evolution of resistance, and evaluating the value of existing tools for resistance monitoring. Based on the lessons taken from resistance strategies used for other vector species and agricultural pests, we propose a framework for the implementation of IRM strategies for Aedes mosquito vectors. CONCLUSIONS AND SIGNIFICANCE: Although IRM should be a fixture of all vector control programs, it is currently often absent from the strategic plans to control mosquito-borne diseases, especially arboviruses. Experiences from other public health disease vectors and agricultural pests underscore the need for urgent action in implementing IRM for invasive Aedes mosquitoes. Based on a plan developed for malaria vectors, here we propose some key activities to establish a global plan for IRM in Aedes spp.


Assuntos
Aedes/virologia , Infecções por Arbovirus/transmissão , Arbovirus/fisiologia , Resistência a Inseticidas , Mosquitos Vetores/virologia , Animais , Febre de Chikungunya/transmissão , Dengue/transmissão , Humanos , Controle de Insetos , Inseticidas/farmacologia , Saúde Pública , Febre Amarela/transmissão , Zika virus , Infecção por Zika virus/transmissão
11.
Parasit Vectors ; 12(1): 417, 2019 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-31488182

RESUMO

BACKGROUND: Sterile male rear-and-release programmes are of growing interest for controlling Aedes aegypti, including use an "incompatible insect technique" (IIT) to suppress transmission of dengue, Zika, and other viruses. Under IIT, males infected with Wolbachia are released into the suppression area to induce cytoplasmic incompatibility in uninfected populations. These and similar mosquito-release programmes require cost-effective field surveys of both sexes to optimize the locations, timing, and quantity of releases. Unfortunately, traps that sample male Ae. aegypti effectively are expensive and usually require mains power. Recently, an electronic lure was developed that attracts males using a 484 Hz sinusoidal tone mimicking the female wingbeat frequencies, broadcast in a 120 s on/off cycle. When deployed in commercially available gravid Aedes traps (GATs), the new combination, sound-GAT (SGAT), captures both males and females effectively. Given its success, there is interest in optimizing SGAT to reduce cost and power usage while maximizing catch rates. METHODS: Options considered in this study included use of a smaller, lower-power microcontroller (Tiny) with either the original or a lower-cost speaker (lcS). A 30 s on/off cycle was tested in addition to the original 120 s cycle to minimize the potential that the longer cycle induced habituation. The original SGAT was compared against other traps incorporating the Tiny-based lures for mosquito capture in a large semi-field cage. The catch rates in waterproofed versions of this trap were then compared with catch rates in standard [BG-Sentinel 2 (BGS 2); Biogents AG, Regensburg, Germany] traps during an IIT field study in the Innisfail region of Queensland, Australia in 2017. RESULTS: The system with a low-power microcontroller and low-cost speaker playing a 30 s tone (Tiny-lcS-30s) caught the highest proportion of males. The mean proportions of males caught in a semi-field cage were not significantly different among the original design and the four low-power, low-cost versions of the SGAT. During the IIT field study, the waterproofed version of the highest-rated, Tiny-lcS-30s SGAT captured male Ae. aegypti at similar rates as co-located BGS-2 traps. CONCLUSIONS: Power- and cost-optimized, waterproofed versions of male Ae. aegypti acoustic lures in GATs are now available for field use in areas with sterile male mosquito rear-and-release programmes.


Assuntos
Aedes/fisiologia , Controle de Mosquitos/instrumentação , Controle de Mosquitos/métodos , Som , Viroses/prevenção & controle , Aedes/virologia , Animais , Custos e Análise de Custo , Dengue/prevenção & controle , Feminino , Masculino , Controle de Mosquitos/economia , Mosquitos Vetores/fisiologia , Mosquitos Vetores/virologia , Infecção por Zika virus/prevenção & controle , Infecção por Zika virus/transmissão
12.
Int J Gynaecol Obstet ; 147(3): 313-318, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31479162

RESUMO

OBJECTIVE: To assess knowledge of the Zika virus (ZIKV), use of contraceptives, and sources of health information in rural communities in the Dominican Republic. METHODS: Over 4 days in March 2017, a research team traveled to four rural communities in the Dominican Republic to provide healthcare services. Overall, 90 men and women consented to a voluntary verbal 12-question survey. RESULTS: Of the participants, 55% were not certain whether ZIKV is transmitted sexually; 75% of participants were either not sure or thought ZIKV was not present in their community. Charlas (informal discussions led by community health workers) were cited as the most common source for public health information. Prevalence of contraceptive use was 26.6% hormonal and 1.1% long-acting reversible contraception (LARC); 30.0% cited no use of contraception. CONCLUSION: Significant deficits in ZIKV knowledge, underutilization of LARCs, and socioeconomic factors exist that constrain the application of WHO recommendations for preventing ZIKV infection. Additional and more robust surveys are needed to assess public health education and interventions, critical for disease prevention in communities facing current and future epidemics.


Assuntos
Comportamento Contraceptivo/estatística & dados numéricos , Educação em Saúde/métodos , Conhecimentos, Atitudes e Prática em Saúde , Infecção por Zika virus/psicologia , Adulto , Estudos Transversais , República Dominicana , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Projetos Piloto , População Rural , Inquéritos e Questionários , Adulto Jovem , Infecção por Zika virus/transmissão
13.
Acta Trop ; 199: 105114, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31442386

RESUMO

In a recent outbreak of Zika virus (ZIKV) infection in Jaipur city (Rajasthan, India), a total of 159 cases were reported in September 2018. In order to identify vector responsible for Zika transmission, mosquitoes were collected from houses with reported Zika cases and nearby houses. A total of 108 pools containing 522 mosquitoes were tested for presence of ZIKV using RT-PCR and Real Time RT-PCR. We detected presence of ZIKV in three pools of Aedes (Stegomyia) aegypti (L.), out of a total of 79 pools with 383 Ae. aegypti through RT-PCR as well as real-time RT-PCR. The presence of ZIKV in Ae. aegypti was further confirmed by DNA sequencing of the partial envelope region of ZIKV. Homology search of DNA sequence revealed highest identity (100%) with a ZIKV isolate from human from the study area which support the role of Ae. aegypti acting as a ZIKV vector. All other mosquitoes (Aedes vittatus and Culex quinquefasciatus) were negative for ZIKV. None of the F1 generation mosquito pools (276 mosquitoes in 43 pools) were found positive. This is the first report of presence of ZIKV in Ae. aegypti from the Indian subcontinent.


Assuntos
Aedes/virologia , Surtos de Doenças , Mosquitos Vetores/virologia , Infecção por Zika virus/transmissão , Zika virus/isolamento & purificação , Animais , Humanos , Índia/epidemiologia , Infecção por Zika virus/epidemiologia
14.
Cien Saude Colet ; 24(8): 2983-2992, 2019 Aug 05.
Artigo em Português, Inglês | MEDLINE | ID: mdl-31389545

RESUMO

Aedes aegypti is currently a critical disease agent and is responsible for viruses such as Zika, Chikungunya and Dengue's four serotypes. This mosquito's relevance to the current social body has come to the fore and triggered urgent EcoHealth investigations since this approach aims to articulate different theoretical fields to understand the historical linkages between nature, society and health. Based on an ethnographic premise, this study considered the unequal and unfair conditions that make women's health vulnerable to dengue, analyzing their practices and perceptions about the potential breeding grounds in the public space. A semi-structured interview and participant observation, as well as a field diary, were used to compose the study. The research included the participation of ten women living in the outskirts of Fortaleza, Ceará, Brazil, from January to August 2014. The category "Social inequality, context and practices in the public space" emerged from the content analysis. The narratives revealed that unstable living conditions and evident social inequality might influence in a context permeated by waste, with great potential for dengue's mosquito proliferation.


Assuntos
Febre de Chikungunya/prevenção & controle , Dengue/prevenção & controle , Controle de Mosquitos/métodos , Infecção por Zika virus/prevenção & controle , Adulto , Aedes/virologia , Idoso , Animais , Brasil , Febre de Chikungunya/transmissão , Dengue/transmissão , Feminino , Humanos , Entrevistas como Assunto , Pessoa de Meia-Idade , Mosquitos Vetores/virologia , Fatores Socioeconômicos , Adulto Jovem , Infecção por Zika virus/transmissão
15.
PLoS Negl Trop Dis ; 13(7): e0007528, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31276467

RESUMO

Extreme weather events affect the development and survival of disease pathogens and vectors. Our aim was to investigate the potential effects of heat waves on the population dynamics of Asian tiger mosquito (Aedes albopictus), which is a major vector of dengue and Zika viruses. We modeled the population abundance of blood-fed mosquito adults based on a mechanistic population model of Ae. albopictus with the consideration of diapause. Using simulated heat wave events derived from a 35-year historical dataset, we assessed how the mosquito population responded to different heat wave characteristics, including the onset day, duration, and the average temperature. Two important observations are made: (1) a heat wave event facilitates the population growth in the early development phase but tends to have an overall inhibitive effect; and (2) two primary factors affecting the development are the unusual onset time of a heat wave and a relatively high temperature over an extended period. We also performed a sensitivity analysis using different heat wave definitions, justifying the robustness of the findings. The study suggests that particular attention should be paid to future heat wave events with an abnormal onset time or a lasting high temperature in order to develop effective strategies to prevent and control Ae. albopictus-borne diseases.


Assuntos
Aedes/fisiologia , Calor Extremo , Mosquitos Vetores/fisiologia , Aedes/virologia , Animais , Febre de Chikungunya/prevenção & controle , Febre de Chikungunya/transmissão , Dengue/prevenção & controle , Dengue/transmissão , Mosquitos Vetores/virologia , Dinâmica Populacional , Infecção por Zika virus/prevenção & controle , Infecção por Zika virus/transmissão
16.
Parasit Vectors ; 12(1): 333, 2019 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-31269965

RESUMO

BACKGROUND: Aedes aegypti and Ae. albopictus are important vectors of infectious diseases, especially those caused by arboviruses such as dengue, chikungunya and Zika. Aedes aegypti is very well adapted to urban environments, whereas Ae. albopictus inhabits more rural settings. Pyrethroid resistance is widespread in these vectors, but limited data exist from the Southwest Pacific Region, especially from Melanesia. While Aedes vector ecology is well documented in Australia, where incursion of Ae. albopictus and pyrethroid resistance have so far been prevented, almost nothing is known about Aedes populations in neighbouring Papua New Guinea (PNG). With pyrethroid resistance documented in parts of Indonesia but not in Australia, it is important to determine the distribution of susceptible and resistant Aedes populations in this region. METHODS: The present study was aimed at assessing Aedes populations for insecticide resistance in Madang and Port Moresby, located on the north and south coasts of PNG, respectively. Mosquitoes were collected using ovitraps and reared in an insectary. Standard WHO bioassays using insecticide-treated filter papers were conducted on a total of 253 Ae. aegypti and 768 Ae. albopictus adult mosquitoes. Subsets of samples from both species (55 Ae. aegypti and 48 Ae. albopictus) were screened for knockdown resistance mutations in the voltage-sensitive sodium channel (Vssc) gene, the target site of pyrethroid insecticides. RESULTS: High levels of resistance against pyrethroids were identified in Ae. aegypti from Madang and Port Moresby. Aedes albopictus exhibited susceptibility to pyrethroids, but moderate levels of resistance to DDT. Mutations associated with pyrethroid resistance were detected in all Ae. aegypti samples screened. Some genotypes found in the present study had been observed previously in Indonesia. No Vssc mutations associated with pyrethroid resistance were found in the Ae. albopictus samples. CONCLUSIONS: To our knowledge, this is the first report of pyrethroid resistance in Ae. aegypti mosquitoes in PNG. Interestingly, usage of insecticides in PNG is low, apart from long-lasting insecticidal nets distributed for malaria control. Further investigations on how these resistant Ae. aegypti mosquito populations arose in PNG and how they are being sustained are warranted.


Assuntos
Aedes/efeitos dos fármacos , Febre de Chikungunya/transmissão , Dengue/transmissão , Resistência a Inseticidas , Mosquitos Vetores/efeitos dos fármacos , Infecção por Zika virus/transmissão , Aedes/virologia , Animais , Arbovirus/fisiologia , Feminino , Inseticidas/farmacologia , Mosquitos Vetores/virologia , Papua Nova Guiné , Piretrinas/farmacologia
17.
Rev Soc Bras Med Trop ; 52: e20180341, 2019 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-31271613

RESUMO

INTRODUCTION: Areas at risk of transmission of arboviruses have been monitored using ovitraps. This study aimed to evaluate the spatial distribution of Aedes aegypti in vulnerable areas for the transmission of arboviruses and assess the influence of climatic conditions on the infestation of these culicids. METHODS: Ovitraps were installed in Agrestina, Pernambuco, Northeastern Brazil. RESULTS: Overall, 44,936 eggs were collected, and the indexes of infestation varied. Relative humidity was significantly associated with the infestations. CONCLUSIONS: Using ovitraps, entomologic indexes and analysis of climatic factors might be good strategies for monitoring vulnerable areas for the transmission of arboviruses.


Assuntos
Arbovirus , Febre de Chikungunya/prevenção & controle , Dengue/prevenção & controle , Controle de Mosquitos/métodos , Oviposição , Infecção por Zika virus/prevenção & controle , Aedes/fisiologia , Animais , Brasil , Febre de Chikungunya/transmissão , Dengue/transmissão , Humanos , Umidade , Mosquitos Vetores/fisiologia , Chuva , Características de Residência , Estações do Ano , Análise Espacial , Temperatura Ambiente , Infecção por Zika virus/transmissão
18.
19.
Emerg Microbes Infect ; 8(1): 1098-1107, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31340725

RESUMO

Studies in mice showed that African Zika virus (ZIKV) strains cause more damage in embryos. These studies, however, were limited to the mouse-adapted African MR766 strain or infection at early gestation. Here, we compared infection of Asian and African strains in the fetal pig model at midgestation. Both strains caused fetal infection. ZIKV was detected in placenta, amniotic membrane, amniotic fluid, fetal blood, and brain. The African strain produced more vigorous in utero infection as represented by more efficient virus transmission between siblings, and higher viral loads in fetal organs and membranes. Infection with both strains was associated with reduced fetal brain weight and increased number of placental CD163-positive cells, as well as elevated in utero interferon alpha and cortisol levels. This is the first large animal model study which demonstrated that African strain of ZIKV, with no passage history in experimental animals, can cause persistent infection in fetuses and fetal membranes at midgestation. Our studies also suggest that similar to Asian strains, ZIKV of African lineage might cause silent pathology which is difficult to identify in deceptively healthy fetuses. The findings emphasize the need for further studies to highlight the impact of ZIKV heterogeneity on infection outcomes during pregnancy.


Assuntos
Doenças Fetais/virologia , Complicações Infecciosas na Gravidez/virologia , Infecção por Zika virus/virologia , Zika virus/fisiologia , Animais , Encéfalo/virologia , Modelos Animais de Doenças , Feminino , Humanos , Placenta/virologia , Gravidez , Suínos , Útero/virologia , Zika virus/classificação , Zika virus/genética , Infecção por Zika virus/transmissão
20.
Parasit Vectors ; 12(1): 363, 2019 Jul 25.
Artigo em Inglês | MEDLINE | ID: mdl-31345269

RESUMO

BACKGROUND: Aedes caspius (Pallas, 1771) is a floodwater mosquito species widely distributed in the Western Palaearctic. As an anthropophilic species, its role as an arbovirus vector may be the key for understanding the transmission cycle of certain diseases in Europe such as Zika virus (ZIKV). Concerning vector competence for ZIKV, studies related to Ae. caspius are still scarce. ZIKV is an arbovirus that has provoked a widespread epidemic in the Pacific region (2007-2013) and in the Americas (2015-2016). ZIKV is associated with serious neurological injuries (e.g. microcephaly) and Guillain-Barré syndrome. Due to the ZIKV epidemics in the American continent, some viraemic travellers coming from endemic countries have been reported in Europe. More knowledge is therefore required to define the susceptibility of autochthonous mosquito species such as Ae. caspius for ZIKV in order to improve arbovirus surveillance and control programmes. In the present study, the vector competence of a European population of Ae. caspius was evaluated for two ZIKV lineages, the Suriname ZIKV strain (Asian lineage) and the MR766 ZIKV strain (African I lineage). Females were tested at 7, 14 and 21 days post-exposure (dpe) to infectious blood meals. An Ae. aegypti PAEA strain was used as a positive control. RESULTS: Aedes caspius presented low susceptibility to ZIKV infection and the virus was only detected by RT-qPCR in body samples. Low viral loads were detected for the MR766 strain at 7 dpe and for the Suriname strain at 14 and 21 dpe. Aedes caspius was unable to produce a disseminated infection and virus transmission at any of the tested time points. Using Ae. aegypti PAEA strain, infection, dissemination and transmission rates were calculated for the Suriname ZIKV strain (Asian lineage) at each time point. For the MR766 ZIKV strain (African I lineage), while only infection rates were estimated at each time point, no dissemination or transmission were detected in either species. CONCLUSIONS: The results of the present study reveal that the tested Ae. caspius population has a strong midgut escape barrier that limits the dissemination or transmission of the virus. As such, it seems unlikely that European Ae. caspius mosquitoes could be involved in ZIKV transmission if ZIKV was introduced into Europe. This information may help in designing a better strategy to European surveillance and control programmes for ZIKV.


Assuntos
Aedes/classificação , Aedes/virologia , Mosquitos Vetores/virologia , Infecção por Zika virus/transmissão , Animais , Europa (Continente) , Feminino , Saliva/virologia , Carga Viral , Zika virus
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