Seasonal Distribution and Climatic Correlates of Dengue Disease in Dhaka, Bangladesh.
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ABSTRACT:
SUBMITTER: Morales I
PROVIDER: S-EPMC4889757 | biostudies-other | 2016 Jun
REPOSITORIES: biostudies-other
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Seasonal Distribution and Climatic Correlates of Dengue Disease in Dhaka, Bangladesh.
Morales Ivonne I Salje Henrik H Saha Samir S Gurley Emily S ES
The American journal of tropical medicine and hygiene 20160425 6
Dengue has been regularly reported in Dhaka, Bangladesh, since a large outbreak in 2000. However, to date, we have limited information on the seasonal distribution of dengue disease and how case distribution correlates with climate. Here, we analyzed dengue cases detected at a private diagnostic facility in Dhaka during 2010-2014. We calculated Pearson cross-correlation coefficients to examine the relationship between the timing of cases and both rainfall and temperature. There were 2,334 cases ...[more]
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Project description:BackgroundDengue virus (DENV) activity has been reported in Dhaka, Bangladesh since the early 1960s with the greatest burden of dengue fever and dengue hemorrhagic fever cases observed in 2000. Since this time, the intensity of dengue activity has varied from year to year, and its determining factors remained relatively unknown. In light of such gaps in knowledge, the main objectives of this study were to determine the magnitude of seroprevalence and seroconversion among the surveyed population, and establish the individual/household level risk factors for the presence of DENV antibodies among all age groups of target populations in the city of Dhaka.Methodology/principal findingsConsidering the lack of fine scale investigations on the factors driving dengue activity in Bangladesh, a prospective cohort study involving serological surveys was undertaken with participant interviews and blood donation across the city of Dhaka in 2012. Study participants were recruited from 12 of 90 wards and blood samples were collected during both the pre-monsoon (n = 1125) and post-monsoon (n = 600) seasons of 2012. The findings revealed that the seroprevalence in all pre-monsoon samples was 80.0% (900/1125) while the seropositivity in the pre-monsoon samples that had paired post-monsoon samples was 83.3% (503/600). Of the 97 paired samples that were negative at the pre-monsoon time point, 56 were positive at the post-monsoon time point. This resulted in a seroprevalence of 93.2% (559/600) among individuals tested during the post-monsoon period. Seroprevalence trended higher with age with children exhibiting a lower seropositivity as compared to adults. Results from this study also indicated that DENV strains were the only flaviviruses circulating in Dhaka in 2012. A multivariate analysis revealed that age, possession of indoor potted plants, and types of mosquito control measures were significant factors associated with DENV seroprevalence; while attendance in public/mass gatherings, and use of mosquito control measures were significantly associated with DENV seroconversion after adjusting for all other variables.Conclusions/significanceOur study suggests that there is a high level of endemic dengue virus circulation in the city of Dhaka which has resulted in significant DENV seroprevalence among its residents. Seropositivity increased with age, however, a substantial proportion of children are at risk for DENV infections. Our serological analysis also documents considerable DENV seroconversion among study participants which indicates that a large proportion of the population in the city of Dhaka were newly exposed to DENV during the study period (pre-and post-monsoon 2012). High levels of seroconversion suggest that there was an intense circulation of DENV in 2012 and this may have resulted in a significant risk for viral associated illness. Findings of our study further indicated that home-based interventions, such as removing indoor potted plants and increased bed net use, in addition to vector control measures in public parks, would reduce exposure to DENV and further decrease risk of viral associated disease.
| S-EPMC5380355 | biostudies-literature
Project description:Dengue, the most important mosquito-borne viral disease of humans is a recurring global health problem. In Bangladesh, dengue outbreaks are on the increase despite the efforts of government and it is not clear what the understanding of the general Dhaka population towards dengue fever is. Knowledge, attitude and practice (KAP) studies are essential guides in public health interventions. Hence, using KAP, this study aims to assess patient-perspectives with regards to factors associated with dengue, as well as investigate the associated factors between the two corporations in Dhaka. A Hospital-based cross-sectional study of 242 fever patients from two city-corporations in Dhaka (Dhaka North City Corporations, DNCC (n = 91, 37.6%) and Dhaka South City Corporation, DSCC (n = 151, 62.4%) was conducted using pre-tested KAP items. Wilcoxon's Rank Sum was used to determine the KAP by DNCC, DSCC and both corporations and multivariate Poisson regression analyses. The two corporations were analysed separately due to the differences in income distribution, concentration of slums, hospitals and clinics. The study found that more than half of the study population were knowledgeable about dengue (mean percentage scores was 52%), possess an appropriate and acceptable attitude towards the disease (69.2%), and about two thirds of the respondents (71.4%) engaged in practices towards its prevention. After adjusting for the potential cofounders, the factors associated with KAP about dengue fever varied between DNCC and DSCC; with duration of residency and use of mosquito nets were associated with knowledge in the north while income class and age were associated with knowledge and attitude in the south. In the pooled analysis (combining both corporations), knowledge of dengue was associated with good practice towards dengue fever among the respondents. The duration of residence in Dhaka (10+ years), not using mosquito nets and length of time spent in the hospital (7+ days) due to dengue, and decreased knowledge (Adjusted coefficient (β) = -0.01, 95%CI: -0.02, -0.01) were associated with attitude towards dengue in DNCC. On the other hand, middle-high income class, age (40+ years) and increased knowledge were associated with practice towards dengue in DSCC (β = 0.02, 95%CI: 0.01, 0.03). Efforts to increase knowledge about dengue fever through education by the administrations of both corporations would benefit from targeting these high-risk groups for a more sustainable outcome.
| S-EPMC8009423 | biostudies-literature
Project description:BackgroundWhile floods can potentially increase the transmission of dengue, only few studies have reported the association of dengue epidemics with flooding. We estimated the effects of river levels and rainfall on the hospital admissions for dengue fever at 11 major hospitals in Dhaka, Bangladesh.MethodsWe examined time-series of the number of hospital admissions of dengue fever in relation to river levels from 2005 to 2009 using generalized linear Poisson regression models adjusting for seasonal, between-year variation, public holidays and temperature.ResultsThere was strong evidence for an increase in dengue fever at high river levels. Hospitalisations increased by 6.9% (95% CI: 3.2, 10.7) for each 0.1 metre increase above a threshold (3.9 metres) for the average river level over lags of 0-5?weeks. Conversely, the number of hospitalisations increased by 29.6% (95% CI: 19.8, 40.2) for a 0.1 metre decrease below the same threshold of the average river level over lags of 0-19?weeks.ConclusionsOur findings provide evidence that factors associated with both high and low river levels increase the hospitalisations of dengue fever cases in Dhaka.
| S-EPMC3528427 | biostudies-literature
Project description: Not available
| S-EPMC8775334 | biostudies-literature
Project description:Local weather influences the transmission of the dengue virus. Most studies analyzing the relationship between dengue and climate are based on relatively coarse aggregate measures such as mean temperature. Here, we include both mean temperature and daily fluctuations in temperature in modelling dengue transmission in Dhaka, the capital of Bangladesh. We used a negative binomial generalized linear model, adjusted for rainfall, anomalies in sea surface temperature (an index for El Niño-Southern Oscillation), population density, the number of dengue cases in the previous month, and the long term temporal trend in dengue incidence. In addition to the significant associations of mean temperature and temperature fluctuation with dengue incidence, we found interaction of mean and temperature fluctuation significantly influences disease transmission at a lag of one month. High mean temperature with low fluctuation increases dengue incidence one month later. Besides temperature, dengue incidence was also influenced by sea surface temperature anomalies in the current and previous month, presumably as a consequence of concomitant anomalies in the annual rainfall cycle. Population density exerted a significant positive influence on dengue incidence indicating increasing risk of dengue in over-populated Dhaka. Understanding these complex relationships between climate, population, and dengue incidence will help inform outbreak prediction and control.
| S-EPMC4498835 | biostudies-literature
Project description:The temporal switching of serotypes from serotype Ogawa to Inaba and back to Ogawa was identified in Vibrio cholerae O1, which was responsible for seasonal outbreaks of cholera in Dhaka during the period 2015 to 2018. In order to delineate the factors responsible for this serotype transition, we performed whole-genome sequencing (WGS) of V. cholerae O1 multidrug-resistant strains belonging to both the serotypes that were isolated during this interval where the emergence and subsequent reduction of the Inaba serotype occurred. The whole-genome-based phylogenetic analysis revealed clonal expansion of the Inaba isolates mainly responsible for the peaks of infection during 2016 to 2017 and that they might have evolved from the prevailing Ogawa strains in 2015 which coclustered with them. Furthermore, the wbeT gene in these Inaba serotype isolates was inactivated due to insertion of a transposable element at the same position signifying the clonal expansion. Also, V. cholerae isolates in the Inaba serotype dominant clade mainly contained classical ctxB allele and revealed differences in the genetic composition of Vibrioseventh pandemic island II (VSP-II) and the SXT integrative and conjugative element (SXT-ICE) compared to those of Ogawa serotype strains which remerged in 2018. The variable presence of phage-inducible chromosomal island-like element 1 (PLE1) was also noted in the isolates of the Inaba serotype dominant clade. The detailed genomic characterization of the sequenced isolates has shed light on the forces which could be responsible for the periodic changes in serotypes of V. cholerae and has also highlighted the need to analyze the mobilome in greater detail to obtain insights into the mechanisms behind serotype switching.IMPORTANCE The switching of serotype from Ogawa to Inaba and back to Ogawa has been observed temporally in Vibrio cholerae O1, which is responsible for endemic cholera in Bangladesh. The serospecificity is key for effective intervention and for preventing cholera, a deadly disease that continues to cause significant morbidity and mortality worldwide. In the present study, WGS of V. cholerae allowed us to better understand the factors associated with the serotype switching events observed during 2015 to 2018. Genomic data analysis of strains isolated during this interval highlighted variations in the genes ctxB, tcpA, and rtxA and also identified significant differences in the genetic content of the mobilome, which included key elements such as SXT ICE, VSP-II, and PLE. Our results indicate that selective forces such as antibiotic resistance and phage resistance might contribute to the clonal expansion and predominance of a particular V. cholerae serotype responsible for an outbreak.
| S-EPMC7018647 | biostudies-literature
Project description:BackgroundThis study examines vector density, the prevailing knowledge, awareness, attitudes and practice (KAAP) of community members regarding dengue disease and their willingness to pay (WTP) for vector control in Dhaka, Bangladesh.MethodsA population-based, cross-sectional study design was followed: (i) an entomological survey was carried out in 727 randomly selected households in 12 wards, representing four urban ecological zones and (ii) a survey of 330 household heads was conducted to study their KAAP. The χ2 test and multinomial logistic regression (MLR) were applied to investigate factors associated with WTP and other variables.ResultsThe Stegomyia indices significantly vary among the urban zones, revealing that the paved and built areas with concentrated public/commercial services have the highest mosquito density. Most respondents (93.9%) knew about dengue and its severity (90.3%); however, many of them were unaware (79.3%) about the types of mosquitoes causing dengue. MLR modelling reveals that average spending per month for mosquito control, household income and knowledge about the effects of land use and seasonality on dengue were significantly associated with the WTP for controlling the dengue vector.ConclusionsConcerted efforts should be made to increase awareness about dengue transmission and develop community-based sustainable dengue vector control programmes involving both the public and private sectors.
| S-EPMC7443721 | biostudies-literature
Project description:This study examined household risk factors and prevalence, abundance, and distribution of immature Aedes aegypti and Aedes albopictus, and their association with socioeconomic and ecological factors at urban zonal and household levels in the city of Dhaka, Bangladesh. During the 2011 monsoon, 826 households in 12 randomly selected administrative wards were surveyed for vector mosquitoes. Results revealed that the abundance and distribution of immature Ae. aegypti and Ae. albopictus, and pupae-per-person indices did not vary significantly among the zones with varied socioeconomic status. Of 35 different types of identified wet containers, 30 were infested, and among the 23 pupae-positive container types, nine were defined as the "most productive" for pupae including: disposable plastic containers (12.2% of 550), sealable plastic barrels (12.0%), tires (10.4%), abandoned plastic buckets (9.6%), flower tub and trays (8.5%), refrigerator trays (6.5%), plastic bottles (6.4%), clay pots (4.9%), and water tanks (1.6%). When the function of the containers was assessed, ornamental, discarded, and household repairing and reconstruction-related container categories were found significantly associated with the number of pupae in the households. The purpose of storing water and income variables were significant predictors of possession of containers that were infested by vector mosquitoes.
| S-EPMC4889738 | biostudies-literature
Project description:BackgroundDengue virus (DENV) infection is one of the biggest challenges for human health in the world. In addition, a secondary DENV infection sometimes causes dengue hemorrhagic fever (DHF), which frequently leads to death. For this reason, accurate diagnosis record management is useful for prediction of DHF. Therefore, the demand for DENV rapid diagnosis tests (RDTs) is increasing because these tests are easy and rapid to use. However, commercially available RDTs often show low sensitivity for DENV and cross-reactivity against other flaviviruses, especially Zika virus (ZIKV).MethodsWe developed two types of novel DENV non-structural protein 1 (NS1) detection RDTs, designated TKK-1st and TKK-2nd kits. Specificities of the monoclonal antibodies (MAbs) used in these kits were confirmed by enzyme-linked immuno-sorbent assay (ELISA), dot blot, and western blot using recombinant NS1 proteins and synthetic peptides. For evaluation of sensitivity, specificity, and cross-reactivity of the novel DENV NS1 RDTs, we first used cultured DENV and other flaviviruses, ZIKV and Japanese encephalitis virus (JEV). We then used clinical specimens obtained in Bangladesh in 2017 for further evaluation of kit sensitivity and specificity in comparison with commercially available RDTs. In addition, RNA extracted from sera were used for viral genome sequencing and genotyping.ResultsEpitopes of three out of four MAbs used in the two novel RDTs were located in amino acid positions 100 to 122 in the NS1 protein, a region that shows low levels of homology with other flaviviruses. Our new kits showed high levels of sensitivity against various serotypes and genotypes of DENV and exhibited high levels of specificity without cross-reactivity against ZIKV and JEV. In clinical specimens, our RDTs showed sensitivities of 96.0% (145/151, TKK-1st kit) and 96.7% (146/151, TKK-2nd kit), and specificities of 98.0% (98/100, TKK-1st kit and TKK-2nd kit). On the other hand, in the case of the commercially available SD Bioline RDT, sensitivity was 83.4% (126/151) and specificity was 99.0% (99/100) against the same clinical specimens.ConclusionsOur novel DENV NS1-targeting RDTs demonstrated high levels of sensitivity and lacked cross-reactivity against ZIKV and JEV compared with commercially available RDTs.
| S-EPMC6694664 | biostudies-literature
Project description:BackgroundDengue, a febrile illness, is caused by a Flavivirus transmitted by Aedes aegypti and Aedes albopictus mosquitoes. Climate influences the ecology of the vectors. We aimed to identify the influence of climatic variability on the occurrence of clinical dengue requiring hospitalization in Zone-5, a high incidence area of Dhaka City Corporation (DCC), Bangladesh.Methods and findingsWe retrospectively identified clinical dengue cases hospitalized from Zone-5 of DCC between 2005 and 2009. We extracted records of the four major catchment hospitals of the study area. The Bangladesh Meteorological Department (BMD) provided data on temperature, rainfall, and humidity of DCC for the study period. We used autoregressive integrated moving average (ARIMA) models for the number of monthly dengue hospitalizations. We also modeled all the climatic variables using Poisson regression. During our study period, dengue occurred throughout the year in Zone-5 of DCC. The median number of hospitalized dengue cases was 9 per month. Dengue incidence increased sharply from June, and reached its peak in August. One additional rainy day per month increased dengue cases in the succeeding month by 6% (RR = 1.06, 95% CI: 1.04-1.09).ConclusionsDengue is transmitted throughout the year in Zone-5 of DCC, with seasonal variation in incidence. The number of rainy days per month is significantly associated with dengue incidence in the subsequent month. Our study suggests the initiation of campaigns in DCC for controlling dengue and other Aedes mosquito borne diseases, including Chikunguniya from the month of May each year. BMD rainfall data may be used to determine campaign timing.
| S-EPMC7765799 | biostudies-literature