Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 17.893
Filter
1.
Article in English | MEDLINE | ID: mdl-33801616

ABSTRACT

The recent spread of invasive mosquito species, such as Aedes albopictus and the seasonal sporadic transmission of autochthonous cases of arboviral diseases (e.g., dengue, chikungunya, Zika) in temperate areas, such as Europe and North America, highlight the importance of effective mosquito-control interventions to reduce not only nuisance, but also major threats for public health. Local, regional, and even national mosquito control programs have been established in many countries and are executed on a seasonal basis by either public or private bodies. In order for these interventions to be worthwhile, funding authorities should ensure that mosquito control is (a) planned by competent scientific institutions addressing the local demands, (b) executed following the plan that is based on recommended and effective methods and strategies, (c) monitored regularly by checking the efficacy of the implemented actions, (d) evaluated against the set of targets, and (e) regularly improved according to the results of the monitoring. Adherence to these conditions can only be assured if a formal quality management system is adopted and enforced that ensures the transparency of effectiveness of the control operation. The current paper aims at defining the two components of this quality management system, quality assurance and quality control for mosquito control programs with special emphasis on Europe, but applicable over temperate areas.


Subject(s)
Aedes , Zika Virus Infection , Zika Virus , Animals , Europe , Mosquito Control , Mosquito Vectors , North America
2.
Parasite ; 28: 37, 2021.
Article in English | MEDLINE | ID: mdl-33861197

ABSTRACT

Mosquitoes transmit several agents of diseases and the presence of different species represents a threat to animal and public health. Aedes and Culex mosquitoes are of particular concern giving their potential vector competence for Arbovirus transmission. In Morocco, the lack of detailed information related to their spatial distribution raises major concerns and hampers effective vector surveillance and control. Using maximum entropy (Maxent) modeling, we generated prediction models for the potential distribution of Arboviruses vectors (Aedes aegypti, Ae. vexans, Ae. caspius, Ae. detritus, and Culex pipiens) in Morocco, under current climatic conditions. Also, we investigated the habitat suitability for the potential occurrence and establishment of Ae. albopictus and Ae. vittatus recorded only once in the country. Prediction models for these last two species were generated considering occurrence datasets from close countries of the Mediterranean Basin, where Ae. albopictus is well established, and from a worldwide database for the case of Ae. vittatus (model transferability). With the exception of Ae. vittatus, the results identify potential habitat suitability in Morocco for all mosquitos considered. Existing areas with maximum risk of establishment and high potential distribution were mainly located in the northwestern and central parts of Morocco. Our results essentially underline the assumption that Ae. albopictus, if not quickly controlled, might find suitable habitats and has the potential to become established, especially in the northwest of the country. These findings may help to better understand the potential distribution of each species and enhance surveillance efforts in areas identified as high risk.


Subject(s)
Aedes , Arboviruses , Animals , Ecosystem , Morocco , Mosquito Vectors
3.
Rev Soc Bras Med Trop ; 54: e0835, 2021.
Article in English | MEDLINE | ID: mdl-33886820

ABSTRACT

INTRODUCTION: Bioprospection of plant products is used to discover new insecticides. METHODS: The larvicidal activity of ethanolic extract and triterpene (tingenone B) from the bark of Maytenus guianensis and their effect on pupation and emergence were evaluated against Aedes aegypti. RESULTS: Crude extract LC50 was 11.3 ppm and caused ejection of the larvae intestine; tingenone B LC50 was 14.8 ppm. Pupation was reduced by 20% and 10%, respectively; however, the emergence was not affected. CONCLUSIONS: The crude bark extract exhibited a higher larvicidal effect against the vector.


Subject(s)
Aedes , Anopheles , Celastraceae , Insecticides , Maytenus , Animals , Insecticides/pharmacology , Larva , Mosquito Vectors , Plant Extracts/pharmacology , Plant Leaves
4.
Pestic Biochem Physiol ; 174: 104823, 2021 May.
Article in English | MEDLINE | ID: mdl-33838716

ABSTRACT

Conventional and volatile pyrethroids are widely used to control the vectors of dengue arboviral diseases, Aedes albopictus in China. The development of resistance to conventional pyrethroids has become an increasing problem, potentially affecting the use of volatile pyrethroid. The Ae. albopictus dimefluthrin-resistant (R) strain by selecting the field population with dimefluthrin were investigated the multiple and cross-resistance levels between conventional and volatile pyrethroids and analyzed both target-site and metabolic resistant mechanisms to dimefluthrin compared with three volatile pyrethroids metofluthrin, meperfluthrin and esbiothrin and type II pyrethroid deltamethrin. The R strain displayed moderate to low resistance to selected pyrethroids (dimefluthrin, metofluthrin, meperfluthrin, esbiothrin and deltamethrin) associated with metabolic enzymes, but less distinctly to selected pyrethroids (dimefluthrin and metofluthrin) associated with a high frequency of sodium channel gene mutation (F1534S). Profiles of the multiple and cross-resistance of the R strain to other three volatile pyrethroids and type II pyrethroid deltamethrin were detected. Both synergistic and enzyme activity studies indicated that multifunctional oxidase (MFO) played an important role in this resistance.


Subject(s)
Aedes , Insecticides , Pyrethrins , Aedes/genetics , Animals , China , Insecticide Resistance/genetics , Insecticides/pharmacology , Mosquito Vectors , Pyrethrins/pharmacology
5.
Arch. argent. pediatr ; 119(2): 131-138, abril 2021. ilus
Article in Spanish | LILACS, BINACIS | ID: biblio-1152134

ABSTRACT

A 11 años del primer brote de dengue en Buenos Aires, el 20 de marzo de 2020, mientras se iniciaba la cuarentena obligatoria por COVID-19, dengue pasó a ser la causa más común de consulta por fiebre. La nueva ola de casos de dengue ya se encontraba entre las predicciones de la Organización Panamericana de la Salud en función del aumento en la región de las Américas que se venía presentando desde el año anterior. La llegada del SARS-CoV-2 a principios de marzo, sumada al brote de dengue que ya estaba en curso, resultó en un nuevo desafío para el sistema de salud, mientras comenzaba un paradigma con planes de adaptación a la nueva infección pandémica en el país. La superposición de infecciones con potencial epidémico, como dengue, recuerda la importancia de no desatender otras enfermedades endémicas, emergentes y reemergentes a la sombra del nuevo fenómeno epidemiológico


Eleven years after the first dengue outbreak in Buenos Aires, on March 20, 2020, while the mandatory quarantine for COVID-19 began dengue became the most common cause of fever consultation. The new wave of dengue cases was already among the predictions of the Pan American Health Organization based on the increase in the region of the Americas that had been occurring since the previous year. The arrival of SARS-CoV-2 at the beginning of March, added to the dengue outbreak that was already underway, made a new challenge for the health system while a new paradigm was initiated with adaptation plans to the new pandemic infection in the country. The overlapping of infections with epidemic potential such as dengue recalls the importance of not neglecting other endemic, emerging and re-emerging diseases in the shadow of the new epidemiological phenomenon.


Subject(s)
Humans , Dengue/epidemiology , Pediatrics , Arboviruses , Argentina/epidemiology , Coronavirus Infections , Aedes , Coinfection
6.
Rev Saude Publica ; 55: 18, 2021.
Article in English | MEDLINE | ID: mdl-33909872

ABSTRACT

OBJECTIVE: To evaluate locomotor activity in four field populations of Ae. aegypti with different insecticide resistance profiles from the state of São Paulo for two years. METHODS: This study comprised the susceptible Rockefeller strain and four populations from São Paulo, Brazil: two considered populations with "reduced susceptibility" to pyrethroids (Campinas and Marília), and two "resistant populations" (Santos and Ribeirão Preto). First, 2016 and 2017 eggs from these five populations were hatched in laboratory. Virgin females underwent experiments under laboratory conditions at 25°C, with 12:12h light/dark (LD) photoperiod; 24-hour individual activity was recorded using a locomotor activity monitor (LAM). RESULTS: In females from 2016 field populations, both resistant populations showed significant more locomotor activity than the two reduced susceptibility populations and the Rockefeller strain (p < 0.05). As for females from 2017 field populations, reduced susceptibility populations showed a significant increased locomotor activity than the Rockefeller strain, but no significant difference when compared to Santos resistant population (p > 0.05). CONCLUSIONS: Our results indicate that insecticide-resistant Ae. aegypti populations show increased locomotor activity, which may affect the transmission dynamics of their arboviruses.


Subject(s)
Aedes , Pyrethrins , Animals , Brazil , Female , Humans , Insecticide Resistance , Locomotion , Pyrethrins/pharmacology
7.
Nat Commun ; 12(1): 2290, 2021 04 16.
Article in English | MEDLINE | ID: mdl-33863888

ABSTRACT

Arthropod-borne viruses pose a major threat to global public health. Thus, innovative strategies for their control and prevention are urgently needed. Here, we exploit the natural capacity of viruses to generate defective viral genomes (DVGs) to their detriment. While DVGs have been described for most viruses, identifying which, if any, can be used as therapeutic agents remains a challenge. We present a combined experimental evolution and computational approach to triage DVG sequence space and pinpoint the fittest deletions, using Zika virus as an arbovirus model. This approach identifies fit DVGs that optimally interfere with wild-type virus infection. We show that the most fit DVGs conserve the open reading frame to maintain the translation of the remaining non-structural proteins, a characteristic that is fundamental across the flavivirus genus. Finally, we demonstrate that the high fitness DVG is antiviral in vivo both in the mammalian host and the mosquito vector, reducing transmission in the latter by up to 90%. Our approach establishes the method to interrogate the DVG fitness landscape, and enables the systematic identification of DVGs that show promise as human therapeutics and vector control strategies to mitigate arbovirus transmission and disease.


Subject(s)
Antiviral Agents/administration & dosage , Defective Viruses/genetics , Mosquito Vectors/drug effects , Zika Virus Infection/drug therapy , Zika Virus/genetics , Aedes/drug effects , Aedes/virology , Animals , Chlorocebus aethiops , Computational Biology , Directed Molecular Evolution , Disease Models, Animal , Female , Genetic Fitness , Genome, Viral/genetics , HEK293 Cells , Humans , Mice , Mosquito Control/methods , Mosquito Vectors/virology , Open Reading Frames/genetics , RNA, Viral/genetics , Vero Cells , Zika Virus Infection/transmission , Zika Virus Infection/virology
8.
Nat Microbiol ; 6(4): 467-478, 2021 04.
Article in English | MEDLINE | ID: mdl-33727702

ABSTRACT

Activation of the RIG-I-like receptors, retinoic-acid inducible gene I (RIG-I) and melanoma differentiation-associated protein 5 (MDA5), establishes an antiviral state by upregulating interferon (IFN)-stimulated genes (ISGs). Among these is ISG15, the mechanistic roles of which in innate immunity still remain enigmatic. In the present study, we report that ISG15 conjugation is essential for antiviral IFN responses mediated by the viral RNA sensor MDA5. ISGylation of the caspase activation and recruitment domains of MDA5 promotes its oligomerization and thereby triggers activation of innate immunity against a range of viruses, including coronaviruses, flaviviruses and picornaviruses. The ISG15-dependent activation of MDA5 is antagonized through direct de-ISGylation mediated by the papain-like protease of SARS-CoV-2, a recently emerged coronavirus that has caused the COVID-19 pandemic. Our work demonstrates a crucial role for ISG15 in the MDA5-mediated antiviral response, and also identifies a key immune evasion mechanism of SARS-CoV-2, which may be targeted for the development of new antivirals and vaccines to combat COVID-19.


Subject(s)
/metabolism , Cytokines/metabolism , Immunity, Innate , Interferon-Induced Helicase, IFIH1/antagonists & inhibitors , /immunology , Ubiquitins/metabolism , Aedes , Animals , Chlorocebus aethiops , Cricetinae , HEK293 Cells , Humans , Interferon-Induced Helicase, IFIH1/metabolism , Leukocytes, Mononuclear , Mice , Vero Cells
9.
RECIIS (Online) ; 15(1): 187-200, jan.-mar. 2021. ilus
Article in Portuguese | LILACS | ID: biblio-1177392

ABSTRACT

A mobilização social para o enfrentamento da dengue, zika, chikungunya e controle do Aedes aegypti tem sido um desafio no país. Esse artigo apresenta o processo de elaboração de uma plataforma virtual, incluindo a composição do seu acervo e a análise exploratória do seu uso, como ferramenta, numa proposta de mobilização social que envolve a criação de comitês populares nos territórios para o enfrentamento das três doenças e vetor. A construção da plataforma considerou: facilidade para usuário; acesso; armazenamento de material; interatividade e banco para monitoramento de dados. A seleção do acervo baseou-se em critérios: técnico, referente à fonte e autoria; acurácia, concordância entre informação e evidência em saúde; e legibilidade, garantindo a compreensão por diferentes grupos. A análise exploratória utilizou o banco de dados da plataforma. Os resultados apontaram a plataforma como uma ferramenta que pode contribuir com a comunicação e informação em saúde nessa proposta de mobilização social.


Social mobilization for dengue, zika and chikungunya prevention and control of Aedes aegypti has been a challenge in the country. This paper presents the process of elaboration of a virtual platform, including the composition of its collection and the exploratory analysis of its use, as a tool in a social mobilization proposal that encompasses the creation of popular committees in the territories for the confrontation of the three diseases and vector. The construction of the platform considered: ease of use; access; material storage; interactivity and database for data monitoring. The selection of the collection was based on the following criteria: technical, considering source and authorship; accuracy, regarding the agreement between health information and evidence; legibility, ensuring the understanding by different groups. The exploratory analysis used the platform database. The results showed the platform as a tool which can contribute to health communication and information in this proposal of social mobilization.


La movilización social para combatir el dengue, zika, chikungunya y control de Aedes ha sido un desafío. Este artículo presenta el proceso de elaboración de una plataforma virtual, que incluye la composición de su acervo y el análisis exploratorio de su uso, como herramienta en una propuesta de movilización social que implica la creación de comités populares en los territorios para enfrentar las enfermedades y el vector. La construcción de la plataforma consideró: facilidad para usuario; acceso; almacenamiento de material; interactividad y bases de datos para el monitoreo. La selección del acervo se basó en criterios: técnico, con fuente y autoría; precisión, concordancia entre información y evidencia en salud; legibilidad, para garantizar la comprensión por diferentes grupos. El análisis utilizó datos de la plataforma. Los resultados mostraron que la plataforma puede ser una herramienta para contribuir a la comunicación e información de salud en esta propuesta de movilización social.


Subject(s)
Humans , Arbovirus Infections , Community Participation , Health Communication , Social Media , Health Promotion , Chikungunya virus , Epidemiology, Descriptive , Aedes , Dengue , Zika Virus
10.
PLoS Negl Trop Dis ; 15(3): e0009259, 2021 03.
Article in English | MEDLINE | ID: mdl-33705409

ABSTRACT

Dengue, Zika and chikungunya are diseases of global health significance caused by arboviruses and transmitted by the mosquito Aedes aegypti, which is of worldwide circulation. The arrival of the Zika and chikungunya viruses to South America increased the complexity of transmission and morbidity caused by these viruses co-circulating in the same vector mosquito species. Here we present an integrated analysis of the reported arbovirus cases between 2007 and 2017 and local climate and socio-economic profiles of three distinct Colombian municipalities (Bello, Cúcuta and Moniquirá). These locations were confirmed as three different ecosystems given their contrasted geographic, climatic and socio-economic profiles. Correlational analyses were conducted with both generalised linear models and generalised additive models for the geographical data. Average temperature, minimum temperature and wind speed were strongly correlated with disease incidence. The transmission of Zika during the 2016 epidemic appeared to decrease circulation of dengue in Cúcuta, an area of sustained high incidence of dengue. Socio-economic factors such as barriers to health and childhood services, inadequate sanitation and poor water supply suggested an unfavourable impact on the transmission of dengue, Zika and chikungunya in all three ecosystems. Socio-demographic influencers were also discussed including the influx of people to Cúcuta, fleeing political and economic instability from neighbouring Venezuela. Aedes aegypti is expanding its range and increasing the global threat of these diseases. It is therefore vital that we learn from the epidemiology of these arboviruses and translate it into an actionable local knowledge base. This is even more acute given the recent historical high of dengue cases in the Americas in 2019, preceding the COVID-19 pandemic, which is itself hampering mosquito control efforts.


Subject(s)
Chikungunya Fever/epidemiology , Dengue/epidemiology , Zika Virus Infection/epidemiology , Aedes/physiology , Aedes/virology , Animals , Chikungunya Fever/economics , Chikungunya Fever/virology , Chikungunya virus/physiology , Climate , Colombia/epidemiology , Dengue/economics , Dengue/virology , Dengue Virus/physiology , Ecosystem , Humans , Mosquito Vectors/physiology , Mosquito Vectors/virology , South America , Temperature , Zika Virus/physiology , Zika Virus Infection/economics , Zika Virus Infection/virology
11.
Nat Commun ; 12(1): 1810, 2021 03 22.
Article in English | MEDLINE | ID: mdl-33753725

ABSTRACT

For most pathogens, transmission is driven by interactions between the behaviours of infectious individuals, the behaviours of the wider population, the local environment, and immunity. Phylogeographic approaches are currently unable to disentangle the relative effects of these competing factors. We develop a spatiotemporally structured phylogenetic framework that addresses these limitations by considering individual transmission events, reconstructed across spatial scales. We apply it to geocoded dengue virus sequences from Thailand (N = 726 over 18 years). We find infected individuals spend 96% of their time in their home community compared to 76% for the susceptible population (mainly children) and 42% for adults. Dynamic pockets of local immunity make transmission more likely in places with high heterotypic immunity and less likely where high homotypic immunity exists. Age-dependent mixing of individuals and vector distributions are not important in determining spread. This approach provides previously unknown insights into one of the most complex disease systems known and will be applicable to other pathogens.


Subject(s)
Algorithms , Dengue Virus/genetics , Dengue/transmission , Models, Theoretical , Adult , Aedes/virology , Animals , Child , Dengue/epidemiology , Dengue/virology , Dengue Virus/classification , Dengue Virus/physiology , Genome, Viral/genetics , Host-Pathogen Interactions , Humans , Mosquito Vectors/virology , Phylogeny , Phylogeography/methods , Phylogeography/statistics & numerical data , Population Dynamics , Thailand/epidemiology
12.
J Vis Exp ; (169)2021 03 12.
Article in English | MEDLINE | ID: mdl-33779612

ABSTRACT

The control of such human diseases as dengue, Zika, and chikungunya relies on the control of their vector, the Aedes aegypti mosquito, because there is no prevention. Control of mosquito vectors can rely on chemicals applied to the immature and adult stages, which can contribute to the mortality of non-targets and more importantly, lead to insecticide resistance in the vector. The sterile insect technique (SIT) is a method of controlling populations of pests through the release of sterilized adult males that mate with wild females to produce non-viable offspring. This paper describes the process of producing sterile males for use in an operational SIT program for the control of Aedes aegypti mosquitoes. Outlined here are the steps used in the program including rearing and maintaining a colony, separating male and female pupae, irradiating and marking adult males, and shipping Aedes aegypti males to the release site. Also discussed are procedural caveats, program limitations, and future objectives.


Subject(s)
Aedes/physiology , Fertility/radiation effects , Insecticide Resistance , Mosquito Control/methods , Mosquito Vectors/physiology , Pupa/physiology , Sterilization, Reproductive/methods , Aedes/radiation effects , Animals , Female , Humans , Male , Mosquito Vectors/radiation effects , Pupa/radiation effects
13.
Rev Soc Bras Med Trop ; 54: e05762020, 2021.
Article in English | MEDLINE | ID: mdl-33656151

ABSTRACT

INTRODUCTION: Aedes aegypti is the main vector of dengue and yellow fever. Recently, the use of plant-sourced larvicides has gained momentum. METHODS: The hydroethanolic extracts and fractions ofOcotea nutansleaves and stems were bioassayed to determine the larvicidal efficacy of these samples. RESULTS: S-HEX (hexane fraction from the crude stem extract) demonstrated high potential for controlling third-stage larvae, with an LC50 of 14.14 µg.mL-1 (concentration required to inhibit 50% of the treated larvae). CONCLUSIONS: Extracts from O. nutans were effective against third-stage larvae ofA. aegyptiafter 24 h of exposure.


Subject(s)
Aedes , Insecticides , Ocotea , Animals , Insecticides/pharmacology , Larva , Mosquito Vectors , Plant Extracts/pharmacology , Plant Leaves
14.
Braz J Biol ; 82: e236498, 2021.
Article in English | MEDLINE | ID: mdl-33787746

ABSTRACT

Mormodica charantia (Curcubitaceae) is a plant with great medicinal potential, also used as an alternative of mosquitoes control as demonstrated by previous studies. We evaluated the larvicidal activity of crude extracts of ethyl acetate, methanol and hexane from flowers and fruits of M. charantia against Aedes aegypti (Culicidae). Flowers and fruits were macerated in methanol, ethyl acetate and hexane. Bioassays were performed with application of the extracts at final concentrations of 1 - 200 µg/mL in the middle of the third instar larvae of A. aegypti (L3). The results showed high toxicity to ethyl acetate extracts from flowers and fruits at concentrations of 200 µg/mL and 100 µg/mL, with 97% and 87% of larvae mortality (L3), respectively. Hexane extract demonstrated low toxicity, while methanol extract exhibited 78% larval mortality. The data suggested that the ethyl acetate extracts of flowers and fruits of M. charantia can effectively contribute to larvicidal activity. In addition, purification of M. charantia extracts may lead to a promising larvicidal activity to control the A. aegypti population.


Subject(s)
Aedes , Insecticides , Momordica charantia , Animals , Insecticides/pharmacology , Larva , Plant Extracts/pharmacology , Plant Leaves
15.
Ecotoxicol Environ Saf ; 213: 112013, 2021 Apr 15.
Article in English | MEDLINE | ID: mdl-33601173

ABSTRACT

Mosquito larvicides are an effective tool for reducing numbers of adult females that bite and potentially spread pathogenic organisms. Methionine, an essential amino acid in humans, has been previously demonstrated to be a highly effective larvicide against four (4) mosquito species in three (3) genera, Anopheles, Culex and Aedes. The aim of the present study was to determine the potential impact on non-target aquatic organisms of methionine applied as a mosquito larvicide. DL-methionine concentrations ranging from 0.06% to 1.00% were used; wherein the highest concentration of 1.00% would result in 100% mortality within 48 h in mosquitoes. Acute toxicity assays were conducted in accordance with the US Environmental Protection Agency (US EPA) guidelines for the water flea (Daphnia magna Straus; Cladocera: Daphniidae) and the fathead minnow (Pimephales promelas Rafinesque; Cypriniformes: Cyprinidae). Water fleas and fish were placed directly into the solutions in glass containers and tanks for 48-hours and 96-hours, respectively. When applied within the above-mentioned range of effective mosquito larvicide concentrations, DL-methionine meets US EPA criteria as a "practically non-toxic" pesticide for both species. These results suggest that methionine is a viable alternative to current mosquito larvicide options, which are typically classified as moderately to highly toxic and may be a valuable addition to a mosquito integrated pest management program.


Subject(s)
Aquatic Organisms , Methionine/toxicity , Mosquito Control , Aedes , Animals , Anopheles , Culex , Cyprinidae , Daphnia , Female , Humans , Larva
16.
Nat Commun ; 12(1): 916, 2021 02 10.
Article in English | MEDLINE | ID: mdl-33568638

ABSTRACT

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


Subject(s)
Zika Virus Infection/mortality , Zika Virus Infection/virology , Zika Virus/physiology , Zika Virus/pathogenicity , Aedes/physiology , Aedes/virology , Africa , Animals , Asia , Female , Humans , Male , Mice , Phylogeny , Virulence , Zika Virus/classification , Zika Virus/genetics , Zika Virus Infection/transmission
17.
Ecol Lett ; 24(4): 698-707, 2021 Apr.
Article in English | MEDLINE | ID: mdl-33554374

ABSTRACT

Recurring seasonal changes can lead to the evolution of phenological cues. For example, many arthropods undergo photoperiodic diapause, a programmed developmental arrest induced by short autumnal day length. The selective mechanisms that determine the timing of autumnal diapause initiation have not been empirically identified. We quantified latitudinal clines in genetically determined diapause timing of an invasive mosquito, Aedes albopictus, on two continents. We show that variation in diapause timing within and between continents is explained by a novel application of a growing degree day (GDD) model that delineates a location-specific deadline after which it is not possible to complete an additional full life cycle. GDD models are widely used to predict spring phenology by modelling growth and development as physiological responses to ambient temperatures. Our results show that the energy accumulation dynamics represented by GDD models have also led to the evolution of an anticipatory life-history cue in autumn.


Subject(s)
Aedes , Introduced Species , Aedes/genetics , Animals , Climate , Photoperiod , Seasons
18.
Environ Res ; 195: 110849, 2021 04.
Article in English | MEDLINE | ID: mdl-33561446

ABSTRACT

BACKGROUND: The mosquitoes Aedes aegypti and Ae. albopictus are the primary vectors of dengue virus, and their geographic distributions are predicted to expand further with economic development, and in response to climate change. We aimed to estimate the impact of future climate change on dengue transmission through the development of a Suitable Conditions Index (SCI), based on climatic variables known to support vectorial capacity. We calculated the SCI based on various climate change scenarios for six countries in the Asia-Pacific region (Australia, China, Indonesia, The Philippines, Thailand and Vietnam). METHODS: Monthly raster climate data (temperature and precipitation) were collected for the period January 2005 to December 2018 along with projected climate estimates for the years 2030, 2050 and 2070 using Representative Concentration Pathway (RCP) 4·5, 6·0 and 8·5 emissions scenarios. We defined suitable temperature ranges for dengue transmission of between 17·05-34·61 °C for Ae. aegypti and 15·84-31·51 °C for Ae. albopictus and then developed a historical and predicted SCI based on weather variability to measure the expected geographic limits of dengue vectorial capacity. Historical and projected SCI values were compared through difference maps for the six countries. FINDINGS: Comparing different emission scenarios across all countries, we found that most South East Asian countries showed either a stable pattern of high suitability, or a potential decline in suitability for both vectors from 2030 to 2070, with a declining pattern particularly evident for Ae. albopictus. Temperate areas of both China and Australia showed a less stable pattern, with both moderate increases and decreases in suitability for each vector in different regions between 2030 and 2070. INTERPRETATION: The SCI will be a useful index for forecasting potential dengue risk distributions in response to climate change, and independently of the effects of human activity. When considered alongside additional correlates of infection such as human population density and socioeconomic development indicators, the SCI could be used to develop an early warning system for dengue transmission.


Subject(s)
Aedes , Dengue , Animals , Australia , China , Climate Change , Dengue/epidemiology , Humans , Indonesia/epidemiology , Mosquito Vectors , Thailand , Vietnam
19.
Environ Res ; 195: 110893, 2021 04.
Article in English | MEDLINE | ID: mdl-33607093

ABSTRACT

The environment, directly and indirectly, affects many mosquito traits in both the larval and adult stages. The availability of food resources is one of the key factors influencing these traits, although its role in mosquito fitness and pathogen transmission remains unclear. Larvae nutritional status determines their survivorship and growth, having also an impact on adult characteristics like longevity, body size, flight capacity or vector competence. During the adult stage, mosquito diet affects their survival rate, fecundity and host-seeking behaviour. It also affects mosquito susceptibility to infection, which may determine the vectorial capacity of mosquito populations. The aim of this review is to critically revise the current knowledge on the effects that both larval and adult quantity and quality of the diet have on mosquito life history traits, identifying the critical knowledge gaps and proposing future research lines. The quantity and quality of food available through their lifetime greatly determine adult body size, longevity or biting frequency, therefore affecting their competence for pathogen transmission. In addition, natural sugar sources for adult mosquitoes, i.e., specific plants providing high metabolic energy, might affect their host-seeking and vertebrate biting behaviour. However, most of the studies are carried out under laboratory conditions, highlighting the need for studies of feeding behaviour of mosquitoes under field conditions. This kind of studies will increase our knowledge of the impact of diets on pathogen transmission, helping to develop successful control plans for vector-borne diseases.


Subject(s)
Aedes , Life History Traits , Animals , Diet , Larva , Mosquito Vectors
20.
Nursing (Säo Paulo) ; 24(273): 5229-5242, fev.2021.
Article in Portuguese | LILACS, BDENF - Nursing | ID: biblio-1148490

ABSTRACT

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


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


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


Subject(s)
Humans , Public Health Nursing , Health Profile , Incidence , Aedes/virology , Dengue/epidemiology , Social Vulnerability Index , Socioeconomic Factors , Disaster Vulnerability/statistics & numerical data , Entomology
SELECTION OF CITATIONS
SEARCH DETAIL
...