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1.
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
2.
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
3.
Environ Monit Assess ; 191(Suppl 2): 393, 2019 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-31254076

RESUMO

India has the largest number of dengue cases in the world, contributing approximately 34% of the global burden. The framework for a geospatially enabled early warning and adaptive response system (EWARS) was first proposed in 2008. It was meant to be a decision support system for enhancing traditional surveillance methods for preventing mosquito-borne diseases in India by utilizing remote sensing data and fuzzy logic-based mathematical predictive modeling. This conceptual paper presents a significant evolution of EWARS such that it synthesizes inputs from not only traditional surveillance and reporting systems for dengue but also from the public via participatory disease surveillance. Two smartphone-based applications have been developed to support EWARS. The first-MOSapp-allows field health workers to upload surveillance data and collect key data on environmental parameters by both direct observation and via portable microclimate stations. The second-DISapp-collects relevant information directly from the community to support participatory disease surveillance. It also gives the user a real-time estimate of the risk of exposure to dengue in proximity to their home and has an educational component that provides information on relevant preventive measures. Both applications utilize a new mosquito abundance measure-the mosquito perception index (MPI)-as reported by the user. These data streams will feed into the EWARS model to generate dynamic risk maps that can guide resource optimization and strengthen disease surveillance, prevention, and response. It is anticipated that such an approach can assist in addressing gaps in the current system of dengue surveillance and control in India.


Assuntos
Aedes/fisiologia , Dengue/prevenção & controle , Aplicativos Móveis , Mosquitos Vetores/fisiologia , Animais , Dengue/epidemiologia , Dengue/transmissão , Monitoramento Epidemiológico , Humanos , Índia/epidemiologia , Modelos Teóricos , Medição de Risco
4.
BMC Infect Dis ; 19(1): 493, 2019 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-31164093

RESUMO

BACKGROUND: Dengue is becoming a major public health concern in Guangdong (GD) Province of China. The problem was highlighted in 2014 by an unprecedented explosive outbreak, where the number of cases was larger than the total cases in previous 30 years. The present study aimed to clarify the spatial and temporal patterns of this dengue outbreak. METHODS: Based on the district/county-level epidemiological, demographic and geographic data, we first used Moran's I statistics and Spatial scan method to uncover spatial autocorrelation and clustering of dengue incidence, and then estimated the spatial distributions of mosquito ovitrap index (MOI) by using inverse distance weighting. We finally employed a multivariate time series model to quantitatively decompose dengue cases into endemic, autoregressive and spatiotemporal components. RESULTS: The results indicated that dengue incidence was highly spatial-autocorrelated with the inclination of clustering and nonuniformity. About 12 dengue clusters were discovered around Guangzhou and Foshan with significant differences by district/county, where the most likely cluster with the largest relative risk located in central Guangzhou in October. Three significant high-MOI areas were observed around Shaoguan, Qingyuan, Shanwei and Guangzhou. It was further found the districts in Guagnzhou and Foshan were prone to local autoregressive transmission, and most region in southern and central GD exhibited higher endemic components. Moreover, nearly all of districts/counties (especially the urban area) have cases that were infected in adjacent regions. CONCLUSIONS: The study can help to clarify the heterogeneity and the associations of dengue transmission in space and time, and thus provide useful information for public health authorities to plan dengue control strategies.


Assuntos
Dengue/epidemiologia , Surtos de Doenças , Animais , China/epidemiologia , Análise por Conglomerados , Culicidae/virologia , Dengue/transmissão , Humanos , Incidência , Insetos Vetores/virologia , Estudos Retrospectivos , Análise Espacial , Análise Espaço-Temporal
5.
Drug Discov Ther ; 13(2): 101-107, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31080200

RESUMO

Acute febrile illness (AFI) is one of the commonest indications for hospitalization and can present with varying severity including single or multiple organ dysfunction syndrome (MODS). During monsoon season, there is a spurt of AFI often caused by vector borne diseases leading to substantial morbidity and mortality. Our aim was to determine distribution of etiological causes, differential organ involvement and predictors of mortality in critically ill patients with AFI. It was a hospital based observational study which included patients with AFI with dysfunction of at least one organ system. The study was conducted over 4 months during monsoon season. Admitted patients were included who had been subjected to a standard battery of tests and managed with standard hospital based management protocol. 145 patients were included and etiology of fever was ascertained in 81.4% of patients with the most common single infection being chikungunya (20.7%) followed by dengue (20%) fever. Thrombocytopenia and deranged liver biochemistry each were seen in nearly 75% of the patients. Renal (50.3%) and nervous system (46.2%) dysfunction were the predominant organ failures. 49 patients died (33.8%) which correlated with predicted mortality by APACHE (acute physiological assessment and chronic health evaluation) II score. Independent predictors for mortality were older age (> 55 years) (p = 0.01), acidemia (p = 0.01), altered sensorium (p = 0.02) and coagulopathy (p = 0.048). Sub-group analysis revealed that amongst patients with MODS, hypotension could help differentiate between bacterial and non-bacterial causes (p = 0.01). Critically ill patients with AFI suffer from significant morbidity and mortality. Features like the presence of hypotension in MODS may differentiate between a bacterial cause vis-à-vis viral or protozoal etiology.


Assuntos
Febre de Chikungunya/epidemiologia , Estado Terminal/mortalidade , Dengue/epidemiologia , Hipotensão/epidemiologia , Insuficiência de Múltiplos Órgãos/etiologia , APACHE , Adolescente , Adulto , Febre de Chikungunya/complicações , Febre de Chikungunya/transmissão , Criança , Dengue/complicações , Dengue/transmissão , Feminino , Humanos , Índia , Masculino , Pessoa de Meia-Idade , Insuficiência de Múltiplos Órgãos/classificação , Insuficiência de Múltiplos Órgãos/mortalidade , Estudos Prospectivos , Fatores de Risco , Estações do Ano , Centros de Atenção Terciária , Adulto Jovem
6.
Pol J Microbiol ; 68(1): 115-119, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31050259

RESUMO

The current study is a retrospective epidemic report regarding dengue fever (DF) virus infection cases (2017) from fifteen districts of KPK, Pakistan. Medical records of 120 948 patients were reviewed retrospectively for demographic, clinical and laboratory data. The presence of dengue infection was confirmed by NS1-ELISA and RT-PCR, respectively. The total positive cases (of suspected DF samples) were 24 938 (20.6%), whereas seventy cases (0.28%) had a fatal outcome. Mean age ± SD of the dengue patients was 26 ± 19.8 years, while; the most affected age group was from 16 to 30 years (Chi-square: 12 820.125, p: 0.00). The infected males were 65.3%, and that of the female was 34.7%. All the dengue-infected patients were observed with symptoms of severe fever (100%), body aches (95%), gums and nose bleeding (5%), skin rashes (30%), vomiting (70%). The highest infection rate was found in district Peshawar and that of the lowest was in Bannu, Hungu and Luki Marwat. A high rate of dengue infection was found in post-monsoon months i.e. October (41%) and September (32%) of the year. The results proved that if the dengue outbreaks reveal further in KPK, it could alarmingly increase the mortality rate. Therefore, the Department of Public Health in KPK, Pakistan may take proper measures to avoid and control dengue epidemics in the future.The current study is a retrospective epidemic report regarding dengue fever (DF) virus infection cases (2017) from fifteen districts of KPK, Pakistan. Medical records of 120 948 patients were reviewed retrospectively for demographic, clinical and laboratory data. The presence of dengue infection was confirmed by NS1-ELISA and RT-PCR, respectively. The total positive cases (of suspected DF samples) were 24 938 (20.6%), whereas seventy cases (0.28%) had a fatal outcome. Mean age ± SD of the dengue patients was 26 ± 19.8 years, while; the most affected age group was from 16 to 30 years (Chi-square: 12 820.125, p: 0.00). The infected males were 65.3%, and that of the female was 34.7%. All the dengue-infected patients were observed with symptoms of severe fever (100%), body aches (95%), gums and nose bleeding (5%), skin rashes (30%), vomiting (70%). The highest infection rate was found in district Peshawar and that of the lowest was in Bannu, Hungu and Luki Marwat. A high rate of dengue infection was found in post-monsoon months i.e. October (41%) and September (32%) of the year. The results proved that if the dengue outbreaks reveal further in KPK, it could alarmingly increase the mortality rate. Therefore, the Department of Public Health in KPK, Pakistan may take proper measures to avoid and control dengue epidemics in the future.


Assuntos
Vírus da Dengue/isolamento & purificação , Dengue/diagnóstico , Dengue/epidemiologia , Monitoramento Epidemiológico , Adolescente , Adulto , Aedes/virologia , Animais , Dengue/transmissão , Surtos de Doenças , Feminino , Geografia , Humanos , Masculino , Paquistão/epidemiologia , Estudos Retrospectivos , Adulto Jovem
7.
Mem Inst Oswaldo Cruz ; 114: e180544, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31038548

RESUMO

BACKGROUND: Aedes aegypti populations in Brazil have been subjected to insecticide selection pressures with variable levels and sources since 1967. Therefore, the Brazilian Ministry of Health (MoH) coordinated the activities of an Ae. aegypti insecticide resistance monitoring network (MoReNAa) from 1999 to 2012. OBJECTIVES: The objective of this study was to consolidate all information available from between 1985 and 2017 regarding the resistance status and mechanisms of Brazilian Ae. aegypti populations against the main insecticide compounds used at the national level, including the larvicide temephos (an organophosphate) and the adulticide deltamethrin (a pyrethroid). METHODS: Data were gathered from two sources: a bibliographic review of studies published from 1985 to 2017, and unpublished data produced by our team within the MoReNAa between 1998 and 2012. A total of 146 municipalities were included, many of which were evaluated several times, totalling 457 evaluations for temephos and 274 for deltamethrin. Insecticide resistance data from the five Brazilian regions were examined separately using annual records of both the MoH supply of insecticides to each state and the dengue incidence in each evaluated municipality. FINDINGS: Ae. aegypti resistance to temephos and deltamethrin, the main larvicide and adulticide, respectively, employed against mosquitoes in Brazil for a long time, was found to be widespread in the country, although with some regional variations. Comparisons between metabolic and target-site resistance mechanisms showed that one or another of these was the main component of pesticide resistance in each studied population. MAIN CONCLUSIONS: (i) A robust dataset on the assessments of the insecticide resistance of Brazilian Ae. aegypti populations performed since 1985 was made available through our study. (ii) Our findings call into question the efficacy of chemical control as the sole methodology of vector control. (iii) It is necessary to ensure that sustainable insecticide resistance monitoring is maintained as a key component of integrated vector management. (iv) Consideration of additional parameters, beyond the supply of insecticides distributed by the MoH or the diverse local dynamics of dengue incidence, is necessary to find consistent correlations with heterogeneous vector resistance profiles.


Assuntos
Aedes/efeitos dos fármacos , Dengue/prevenção & controle , Resistência a Inseticidas/efeitos dos fármacos , Inseticidas/farmacologia , Mosquitos Vetores/efeitos dos fármacos , Nitrilos/farmacologia , Piretrinas/farmacologia , Temefós/farmacologia , Animais , Bioensaio , Brasil/epidemiologia , Dengue/epidemiologia , Dengue/transmissão , Incidência , Inseticidas/administração & dosagem , Nitrilos/administração & dosagem , Piretrinas/administração & dosagem , Temefós/administração & dosagem
8.
Parasit Vectors ; 12(1): 236, 2019 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-31097010

RESUMO

BACKGROUND: Dengue is a serious public health problem worldwide, including in Selangor, Malaysia. Being an important vector of dengue virus, Aedes aegypti are subjected to control measures which rely heavily on the usage of insecticides. Evidently, insecticide resistance in Ae. aegypti, which arise from several different point mutations within the voltage-gated sodium channel genes, has been documented in many countries. Thus, this robust study was conducted in all nine districts of Selangor to understand the mechanisms of resistance to various insecticides in Ae. aegypti. Mosquitoes were collected from dengue epidemic and non-dengue outbreak areas in Selangor. METHODS: Using the Center for Disease Control and Prevention (CDC) bottle assays, the insecticide resistance status of nine different Ae. aegypti strains from Selangor was accessed. Synergism tests and biochemical assays were conducted to further understand the metabolic mechanisms of insecticide resistance. Polymerase chain reaction (PCR) amplification and sequencing of the IIP-IIS6 as well as IIIS4-IIIS6 regions of the sodium channel gene were performed to enable comparisons between susceptible and resistant mosquito strains. Additionally, genomic DNA was used for allele-specific PCR (AS-PCR) genotyping of the gene to detect the presence of F1534C, V1016G and S989P mutations. RESULTS: Adult female Ae. aegypti from various locations were susceptible to malathion and propoxur. However, they exhibited different levels of resistance against dichlorodiphenyltrichloroethane (DDT) and pyrethroids. The results of synergism tests and biochemical assays indicated that the mixed functions of oxidases and glutathione S-transferases contributed to the DDT and pyrethroid resistance observed in the present study. Besides detecting three single kdr mutations, namely F1534C, V1016G and S989P, co-occurrence of homozygous V1016G/S989P (double allele) and F1534C/V1016G/S989P (triple allele) mutations were also found in Ae. aegypti. As per the results, the three kdr mutations had positive correlations with the expressions of resistance to DDT and pyrethroids. CONCLUSIONS: In view of the above outcomes, it is important to seek new tools for vector management instead of merely relying on insecticides. If the latter must be used, regular monitoring of insecticide resistance should also be carried out at all dengue epidemic areas. Since the eggs of Ae. aegypti can be easily transferred from one location to another, it is probable that insecticide-resistant Ae. aegypti can be found at non-dengue outbreak sites as well.


Assuntos
Aedes/enzimologia , Aedes/genética , Resistência a Inseticidas/genética , Mosquitos Vetores/genética , Alelos , Animais , Dengue/transmissão , Feminino , Genótipo , Glutationa Transferase/genética , Proteínas de Insetos/genética , Inseticidas , Malation , Malásia , Mosquitos Vetores/enzimologia , Mutação , Oxirredutases/genética , Reação em Cadeia da Polimerase , Piretrinas , Análise de Sequência de DNA , Canais de Sódio/genética
10.
PLoS Negl Trop Dis ; 13(4): e0007298, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30986218

RESUMO

Only a few studies have investigated the potential of using geotagged social media data for predicting the patterns of spatio-temporal spread of vector-borne diseases. We herein demonstrated the role of human mobility in the intra-urban spread of dengue by weighting local incidence data with geo-tagged Twitter data as a proxy for human mobility across 45 neighborhoods in Yogyakarta city, Indonesia. To estimate the dengue virus importation pressure in each study neighborhood monthly, we developed an algorithm to estimate a dynamic mobility-weighted incidence index (MI), which quantifies the level of exposure to virus importation in any given neighborhood. Using a Bayesian spatio-temporal regression model, we estimated the coefficients and predictiveness of the MI index for lags up to 6 months. Specifically, we used a Poisson regression model with an unstructured spatial covariance matrix. We compared the predictability of the MI index to that of the dengue incidence rate over the preceding months in the same neighborhood (autocorrelation) and that of the mobility information alone. We based our estimates on a volume of 1·302·405 geotagged tweets (from 118·114 unique users) and monthly dengue incidence data for the 45 study neighborhoods in Yogyakarta city over the period from August 2016 to June 2018. The MI index, as a standalone variable, had the highest explanatory power for predicting dengue transmission risk in the study neighborhoods, with the greatest predictive ability at a 3-months lead time. The MI index was a better predictor of the dengue risk in a neighborhood than the recent transmission patterns in the same neighborhood, or just the mobility patterns between neighborhoods. Our results suggest that human mobility is an important driver of the spread of dengue within cities when combined with information on local circulation of the dengue virus. The geotagged Twitter data can provide important information on human mobility patterns to improve our understanding of the direction and the risk of spread of diseases, such as dengue. The proposed MI index together with traditional data sources can provide useful information for the development of more accurate and efficient early warning and response systems.


Assuntos
Dengue/epidemiologia , Transmissão de Doença Infecciosa , Métodos Epidemiológicos , Mídias Sociais , Topografia Médica , Viagem/estatística & dados numéricos , População Urbana , Dengue/transmissão , Humanos , Incidência , Indonésia/epidemiologia , Procurador , Análise Espaço-Temporal , Doença Relacionada a Viagens
11.
Artigo em Inglês | MEDLINE | ID: mdl-30970109

RESUMO

Aedes aegypti and Aedes albopictus are exotic species in the Americas with high epidemiological relevance as they are vectors of many pathogens. This study aimed at understanding the population dynamics of A. aegypti and A. albopictus and the influence of abiotic factors in an endemic area of dengue. The study was conducted in the urban area of Campo Grande, Mato Grosso do Sul, Brazil, over one year. In seven regions of the city, 50 ovitraps were installed in each neighborhood. The development of the larvae was monitored under controlled laboratory conditions until they reached the adult phase. A total of 50,900 eggs of Aedes sp. were collected, 26,073 of which reached adulthood: 25,496 (97.8 %) A. aegypti and 540 (2.1%) A. albopictus. A. aegypti was observed in all months during the study. The highest number of A. albopictus eggs were collected in June, while in August and September, an absence of this species was noted. Abiotic factors such as temperature, humidity and rainfall were responsible for the observed fluctuations in the mosquito population. The presence of A. albopictus in the urban area of the city is concerning because it could become a potential vector for other arboviruses that afflict human populations. The occurrence of these species in Campo Grande reinforces the need for constant entomological and epidemiological surveillance so that informed actions could be taken to decrease potential breeding sites.


Assuntos
Aedes/fisiologia , Mosquitos Vetores/fisiologia , Oviposição/fisiologia , Aedes/classificação , Animais , Brasil , Dengue/transmissão , Doenças Endêmicas , Feminino , Estágios do Ciclo de Vida , Masculino , Mosquitos Vetores/classificação , Densidade Demográfica , Dinâmica Populacional , Estações do Ano , População Urbana
12.
Rev Saude Publica ; 53: 29, 2019 Apr 01.
Artigo em Inglês, Português | MEDLINE | ID: mdl-30942271

RESUMO

OBJECTIVE: To evaluate whether sites with large amount of potential breeding sites for immature forms of Aedes aegypti, called strategic points, influence in the active vector's dispersion into properties in their surroundings. METHODS: We selected four areas in the municipality of Campinas, three of them with strategic points classified as high, moderate, and low risk according to infestation and a control area, without strategic points. Between October 2015 and September 2016, we monthly installed oviposition traps and evaluated the infestation by Ae. aegypti in all properties of each selected area. To verify if there was vector dispersion from each strategic point, based on its location, we investigated the formation of clusters with excess of eggs or larvae or pupae containers, using the Gi spatial statistics. RESULTS: The amount of eggs collected in the ovitraps and the number of positive containers for Ae. aegypti did not show clusters of high values concerning its distance from the strategic point. Both presented random distribution not spatially associated with the positioning of strategic points in the area. CONCLUSIONS: Strategic points are not confirmed as responsible for the vector's dispersion for properties in their surroundings. We highlight the importance of reviewing the current strategy of the vector control program in Brazil, seeking a balance from the technical, operational, and economic point of view, without disregarding the role of strategic points as major producers of mosquitoes and their importance in the dissemination of arboviruses in periods of transmission.


Assuntos
Aedes/crescimento & desenvolvimento , Dengue/prevenção & controle , Controle de Mosquitos/métodos , Mosquitos Vetores/crescimento & desenvolvimento , Oviposição/fisiologia , Pupa/crescimento & desenvolvimento , Aedes/virologia , Distribuição Animal/fisiologia , Animais , Brasil , Dengue/transmissão , Monitoramento Ambiental , Feminino , Controle de Mosquitos/estatística & dados numéricos , Mosquitos Vetores/virologia , Fatores de Risco , Análise Espacial , População Urbana
13.
Indian Pediatr ; 56(2): 123-125, 2019 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-30819991

RESUMO

OBJECTIVE: To study the five year trend of epidemiological and demographic characteristics of dengue infections from year 2013 to 2017 among children upto 15 years. METHODS: This study presents data from review of microbiology department records of samples for dengue testing with information supplied by clinicians on the investigation request form. Patients were tested for NS1 Ag, IgM Ab or both. RESULTS: Out of 4216 samples, 1072 (25.4%) were positive for dengue. Positivity ranged from 44.2% in year 2013, 25.8% in 2015 to 16.2% in year 2017. Most cases reported were among male (57.9%), from urban areas (77.9%) and Rajkot district (75.7%). Reporting of dengue cases increased from July to November with peak during October every year. CONCLUSIONS: Serum samples for dengue serology were more commonly positive in July-September months during the study period, and in male children, and those from urban areas.


Assuntos
Dengue/epidemiologia , Adolescente , Criança , Pré-Escolar , Dengue/transmissão , Feminino , Hospitalização , Humanos , Índia/epidemiologia , Lactente , Recém-Nascido , Masculino , Estações do Ano
14.
Glob Health Sci Pract ; 7(1): 128-137, 2019 03 22.
Artigo em Inglês | MEDLINE | ID: mdl-30926741

RESUMO

In Colombia, as in many Latin American countries, decision making and development of effective strategies for vector control of urban diseases such as dengue, Zika, and chikungunya is challenging for local health authorities. The heterogeneity of transmission in urban areas requires an efficient risk-based allocation of resources to control measures. With the objective of strengthening the capacity of local surveillance systems to identify variables that favor urban arboviral transmission, a multidisciplinary research team collaborated with the local Secretary of Health officials of 3 municipalities in Colombia (Giron, Yopal, and Buga), in the design of an integrated information system called VECTOS from 2015 to 2018. Information and communication technologies were used to develop 2 mobile applications to capture entomological and social information, as well as a web-based system for the collection, geo-referencing, and integrated information analysis using free geospatial software. This system facilitates the capture and analysis of epidemiological information from the Colombian national surveillance system (SIVIGILA), periodic entomological surveys-mosquito larvae and pupae in premises and peridomestic breeding sites-and surveys of knowledge, attitudes, and practices (KAP) in a spatial and temporal context at the neighborhood level. The data collected in VECTOS are mapped and visualized in graphical reports. The system enables real-time monitoring of weekly epidemiological indicators, entomological indices, and social surveys. Additionally, the system enables risk stratification of neighborhoods, using selected epidemiological, entomological, demographic, and environmental variables. This article describes the VECTOS system and the lessons learned during its development and use. The joint analysis of epidemiological and entomological data within a geographic information system in VECTOS gives better insight to the routinely collected data and identifies the heterogeneity of risk factors between neighborhoods. We expect the system to continue to strengthen vector control programs in evidence-based decision making and in the design and enhanced follow-up of vector control strategies.


Assuntos
Infecções por Arbovirus/prevenção & controle , Tomada de Decisões , Sistemas de Informação , Aplicativos Móveis , Controle de Mosquitos , Tecnologia , População Urbana , Infecções por Arbovirus/transmissão , Infecções por Arbovirus/virologia , Arbovirus/crescimento & desenvolvimento , Febre de Chikungunya/etiologia , Febre de Chikungunya/transmissão , Cidades , Colômbia , Análise de Dados , Coleta de Dados , Dengue/etiologia , Dengue/transmissão , Monitoramento Ambiental/métodos , Sistemas de Informação Geográfica , Humanos , Internet , Mosquitos Vetores/crescimento & desenvolvimento , Mosquitos Vetores/virologia , Vigilância da População , Saúde Pública , Características de Residência , Fatores de Risco , Infecção por Zika virus/etiologia , Infecção por Zika virus/transmissão
15.
Mem Inst Oswaldo Cruz ; 114: e180318, 2019 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-30916115

RESUMO

BACKGROUND: The longstanding application of insecticides for vector control without periodic monitoring of the population response to these chemicals can directly drive the selection of resistant populations of vector mosquitoes. Tocantins is the newest state of the Brazilian Federation. Despite a historically high number of dengue cases, studies and monitoring data concerning insecticide resistance in the state are lacking. OBJECTIVES: To verify the resistance status of Aedes aegypti from 10 populations distributed throughout the state connected by rivers and roads. METHODS: Between 50 and 150 ovitraps were installed in house gardens within each municipality. Collection points were established based on the importance of the towns and on geographic aspects. Dose response bioassays were performed in accordance with World Health Organization guidelines. Molecular assays were conducted to detect kdr mutations, which are related to pyrethroid resistance. FINDINGS: Of the 3,200 ovitrap paddles analysed, 25.8% contained eggs, with a total of 55,687 eggs collected. With the exception of Caseara, all evaluated populations were considered to be resistant to temephos. The data showed different levels of resistance to deltamethrin among the samples. Caseara and Guaraí showed the lowest RR95 values. On average, the NaVR1 kdr allele was most frequent (40.3%), followed by NaVS (38.1%), and NaVR2 (21.6%). Palmas, the capital of the state, had the highest frequency of kdr alleles (87.5%). MAIN CONCLUSIONS: With the exception of Palmas, the towns with the highest indexes (ovitrap positivity, number and density of eggs), as well with high levels of resistance and kdr alleles were located along the BR-153 road, indicating that the flow of people and cargo can contribute to the dispersion of the vector and potentially resistance. This study contributes substantially to knowledge regarding the insecticide resistance profile of Tocantins mosquito populations; the data generated via the study could facilitate the judicious use of insecticides by vector control programs.


Assuntos
Aedes/efeitos dos fármacos , Resistência a Inseticidas/genética , Inseticidas/farmacologia , Mosquitos Vetores/efeitos dos fármacos , Temefós/farmacologia , Aedes/genética , Animais , Brasil , Dengue/transmissão , Feminino , Genótipo , Resistência a Inseticidas/efeitos dos fármacos , Masculino , Mosquitos Vetores/genética , Mutação , Rios
16.
Artigo em Inglês | MEDLINE | ID: mdl-30841574

RESUMO

In this work, a two-strain dengue model with vertical transmission in the mosquito population is considered. Although vertical transmission is often ignored in models of dengue fever, we show that effective control of an outbreak of dengue can depend on whether or not the vertical transmission is a significant mode of disease transmission. We model the effect of a control strategy aimed at reducing human-mosquito transmissions in an optimal control framework. As the likelihood of vertical transmission increases, outbreaks become more difficult and expensive to control. However, even for low levels of vertical transmission, the additional, uncontrolled, transmission from infected mosquito to eggs may undercut the effectiveness of any control function. This is of particular importance in regions where existing control policies may be effective and the endemic strain does not exhibit vertical transmission. If a novel strain that does exhibit vertical transmission invades, then existing, formerly effective, control policies may no longer be sufficient. Therefore, public health officials should pay more attention to the role of vertical transmission for more effective interventions and policy.


Assuntos
Dengue/transmissão , Transmissão Vertical de Doença Infecciosa , Animais , Culicidae , Dengue/prevenção & controle , Vírus da Dengue , Surtos de Doenças/prevenção & controle , Humanos
17.
Artigo em Inglês | MEDLINE | ID: mdl-30813470

RESUMO

Dengue´s re-emerging epidemiology poses a major global health threat. In India, dengue contributes significantly to the global communicable disease burden, and has been declared highly endemic. This study aims to identify and critically appraise India's dengue surveillance system. We conducted a systematic literature review, searching Medline, Web of Sciences, Global Health, and Indian Journals. We conducted a narrative synthesis and thematic analysis. Eighteen studies fulfilled eligibility. Organizationally, most studies referred to the National Vector Borne Disease Control Programme, primarily responsible for overall vector and disease control, as well as the Integrated Disease Surveillance Programme, responsible for reporting, outbreak identification, and integration. Surveillance implementation was mostly framed as passive, sentinel, and hospital-based. Reporting varies from weekly to monthly, flowing from primary healthcare centres to district and national authorities. Dengue confirmation is only recognized if conducted with government-distributed MAC-ELISA tests. The surveillance system predominantly relies on public reporting units. In terms of functioning, current surveillance seems to have improved dengue reporting as well the system's detection capacities. Emergency and outbreak responses are often described as timely; however, they are challenged by underreporting, weak data reliability, lack of private reporting, and system fragmentation. Concluding, India's dengue surveillance structure remains weak. Efforts to create an infrastructure of communication, cooperation, and integration are evident, however, not achieved yet.


Assuntos
Doenças Transmissíveis/epidemiologia , Dengue/epidemiologia , Vigilância da População , Doenças Transmissíveis/transmissão , Dengue/transmissão , Surtos de Doenças , Humanos , Índia/epidemiologia , Mosquitos Vetores , Reprodutibilidade dos Testes
18.
Biomed Res Int ; 2019: 2950216, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30834259

RESUMO

Constant monitoring of Aedes vector indices such as Aedes mosquito abundance and ovitrap data is important for the control of dengue epidemics. Therefore, the current study attempted to evaluate the effect of larval and climatic factors on the incidence of dengue outbreaks in the Gampaha district. Based on the distribution of previously reported dengue cases, 34 households in Narangodapaluwa PHI area, Ragama, Sri Lanka, were selected randomly, and entomological surveillance was done fortnightly using adult mosquito catches and larval surveillance techniques for a period of two years. Further, weekly ovitrap surveillance was conducted for one year, by maintaining four ovitraps in a single house, two indoors and two outdoors at ground and at a height of 1.5-2 m. Based on the findings, larval indices, namely, Breteau index (BI), House index (HI), and Container index (CI), were calculated, along with the Ovitrap index (OI). The study area was positive for Ae. albopictus with an adult capturing range of 1~15/34 households. BI initially remained < 3%, which subsequently decreased up to 0. No significant difference in OI was found between the ovitraps placed at ground level and at a height of 1.5-2m (p>0.05), 95% level of confidence. The OI varied from 56.9% to 94.7% during the study period of 12 months, indicating two peaks at the monsoons. Statistics of one-way ANOVA revealed a significant difference in the monthly OI during the study period (p≤0.001) with two peaks representing the monsoonal rainfall patterns. Pearson's correlation analysis revealed that the association between dengue cases and larval indices (BI, CI, HI, and OI) and meteorological parameters was not significant (p<0.05). Migration of mosquitoes and patients could be considered as possible factors affecting the absence of a significant relationship.


Assuntos
Aedes/virologia , Vírus da Dengue/patogenicidade , Dengue/transmissão , Mosquitos Vetores/virologia , Aedes/genética , Animais , Dengue/epidemiologia , Dengue/genética , Dengue/virologia , Vírus da Dengue/genética , Surtos de Doenças , Vetores de Doenças , Feminino , Humanos , Larva/genética , Larva/virologia , Controle de Mosquitos , Mosquitos Vetores/genética , Densidade Demográfica
19.
PLoS Comput Biol ; 15(3): e1006831, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30849074

RESUMO

Management of vector population is a commonly used method for mitigating transmission of mosquito-borne infections, but quantitative information on its practical public health impact is scarce. We study the effectiveness of Ultra-Low Volume (ULV) insecticide spraying in public spaces for preventing secondary dengue virus (DENV) cases in Porto Alegre, a non-endemic metropolitan area in Brazil. We developed a stochastic transmission model based on detailed entomological, epidemiological and population data, accounting for the geographical distribution of mosquitoes and humans in the study area and spatial transmission dynamics. The model was calibrated against the distribution of DENV cluster sizes previously estimated from the same geographical setting. We estimated a ULV-induced mortality of 40% for mosquitoes and found that the implemented control protocol avoided about 24% of symptomatic cases occurred in the area throughout the 2015-2016 epidemic season. Increasing the radius of treatment or the mortality of mosquitoes by treating gardens and/or indoor premises would greatly improve the result of control, but trade-offs with respect to increased efforts need to be carefully analyzed. We found a moderate effectiveness for ULV-spraying in public areas, mainly due to the limited ability of this strategy in effectively controlling the vector population. These results can be used to support the design of control strategies in low-incidence, non-endemic settings.


Assuntos
Dengue/prevenção & controle , Inseticidas , Controle de Mosquitos/métodos , Animais , Brasil/epidemiologia , Análise por Conglomerados , Dengue/epidemiologia , Dengue/transmissão , Humanos , Incidência , Mosquitos Vetores
20.
PLoS Comput Biol ; 15(3): e1006710, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30893294

RESUMO

Prophylactic vaccination is a powerful tool for reducing the burden of infectious diseases, due to a combination of direct protection of vaccinees and indirect protection of others via herd immunity. Computational models play an important role in devising strategies for vaccination by making projections of its impacts on public health. Such projections are subject to uncertainty about numerous factors, however. For example, many vaccine efficacy trials focus on measuring protection against disease rather than protection against infection, leaving the extent of breakthrough infections (i.e., disease ameliorated but infection unimpeded) among vaccinees unknown. Our goal in this study was to quantify the extent to which uncertainty about breakthrough infections results in uncertainty about vaccination impact, with a focus on vaccines for dengue. To realistically account for the many forms of heterogeneity in dengue virus (DENV) transmission, which could have implications for the dynamics of indirect protection, we used a stochastic, agent-based model for DENV transmission informed by more than a decade of empirical studies in the city of Iquitos, Peru. Following 20 years of routine vaccination of nine-year-old children at 80% coverage, projections of the proportion of disease episodes averted varied by a factor of 1.76 (95% CI: 1.54-2.06) across the range of uncertainty about breakthrough infections. This was equivalent to the range of vaccination impact projected across a range of uncertainty about vaccine efficacy of 0.268 (95% CI: 0.210-0.329). Until uncertainty about breakthrough infections can be addressed empirically, our results demonstrate the importance of accounting for it in models of vaccination impact.


Assuntos
Dengue/prevenção & controle , Dengue/transmissão , Análise de Sistemas , Incerteza , Vacinas Virais/administração & dosagem , Calibragem , Criança , Simulação por Computador , Humanos , Peru
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