Demographic drivers of Norway rat populations from urban slums in Brazil
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ABSTRACT: Supplementary Information
The online version contains supplementary material available at 10.1007/s11252-020-01075-2.
SUBMITTER: Zeppelini C
PROVIDER: S-EPMC8550123 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:The Norway rat, Rattus norvegicus, is one of the most important pest species globally and the main reservoir of leptospires causing human leptospirosis in the urban slums of tropical regions. Rodent control is a frequent strategy in those settings to prevent the disease but rapid growth from residual populations and immigration limit the long-term effectiveness of interventions. To characterize the breeding ecology of R. norvegicus and provide needed information for the level of genetic mixing, which can help identify inter-connected eradication units, we estimated the occurrence of multiple paternity, distances between mothers and sires, and inbreeding in rats from urban slum habitat in Salvador, Brazil. We genotyped 9 pregnant females, their 66 offspring, and 371 males at 16 microsatellite loci. Multiple paternity was observed in 22% (2/9) of the study litters. Of the 12 sires that contributed to the 9 litters, we identified 5 (42%) of those sires among our genotyped males. Related males were captured in close proximity to pregnant females (the mean inter-parent trapping distance per litter was 70 m, ±58 m SD). Levels of relatedness between mother-sire pairs were higher than expected and significantly higher than relatedness between all females and non-sire males. Our findings indicate multiple paternity is common, inbreeding is apparent, and that mother-sire dyads occur in close proximity within the study area. This information is relevant to improve the spatial definition of the eradication units that may enhance the effectiveness of rodent management programs aimed at preventing human leptospirosis. High levels of inbreeding may also be a sign that eradication efforts are successful.
| S-EPMC5893012 | biostudies-literature
Project description:In Norway, as in many other rich countries, childlessness is more common among men than women and has also increased more among men. Over the last 15 years, the gap in childlessness between 45-year-old women and men has widened from 5.8 to 10.2 percentage points, according to national register data. In the Norwegian-born subgroup, the gap has increased by 2.4 percentage points, from 5.8 to 8.2. The goal of the study was to identify the demographic drivers of this development, using a quite simple, but original, decomposition approach. The components reflect changes in relative cohort sizes, whether the child has one native and one immigrant parent, whether the father was older than 45, and whether one of the parents already had a child, no longer lived in Norway at age 45, or was unidentified. It was found that the modestly increasing sex gap in childlessness among the Norwegian-born is largely linked to changes in cohort sizes, i.e. fertility trends. Changes in re-partnership have actually contributed weakly in the opposite direction: It has become more common especially among men to have the first child with a partner who already had a child, and thus not contribute to bringing also that person out of childlessness. The importance of the various components is different for immigrants, among whom the sex gap in childlessness has increased particularly much. This development may also reflect that especially male immigrants perhaps have children in the home country who are not included in the Norwegian register.Supplementary informationThe online version contains supplementary material available at 10.1007/s10680-021-09590-4.
| S-EPMC8575743 | biostudies-literature
Project description:Norway rats (Rattus norvegicus) living in urban environments are a critical public health and economic problem, particularly in urban slums where residents are at a higher risk for rat borne diseases, yet convenient methods to quantitatively assess population sizes are lacking. We evaluated track plates as a method to determine rat distribution and relative abundance in a complex urban slum environment by correlating the presence and intensity of rat-specific marks on track plates with findings from rat infestation surveys and trapping of rats to population exhaustion. To integrate the zero-inflated track plate data we developed a two-component mixture model with one binary and one censored continuous component. Track plate mark-intensity was highly correlated with signs of rodent infestation (all coefficients between 0.61 and 0.79 and all p-values < 0.05). Moreover, the mean level of pre-trapping rat-mark intensity on plates was significantly associated with the number of rats captured subsequently (Odds ratio1.38; 95% CI 1.19-1.61) and declined significantly following trapping (Odds ratio 0.86; 95% CI 0.78-0.95). Track plates provided robust proxy measurements of rat abundance and distribution and detected rat presence even when populations appeared 'trapped out'. Tracking plates are relatively easy and inexpensive methods that can be used to intensively sample settings such as urban slums, where traditional trapping or mark-recapture studies are impossible to implement, and therefore the results can inform and assess the impact of targeted urban rodent control campaigns.
| S-EPMC4955619 | biostudies-literature
Project description:While research on the nexus of migration and wellbeing of individuals has gained recognition in recent years, far less attention has been devoted to intra-urban mobility especially among the urban poor young populations. We assess the drivers of intra-urban mobility using a random sample of 412 migrant street children and youth in Kampala city, Uganda. This paper draws from a larger cross-sectional survey of circular migration and sexual and reproductive health choices among street children in Kampala, Uganda. We define 'migrants' as street children and youth with a rural-urban migration experience and 'intra-urban mobility' as the number of places stayed in or moved since migrating to the city, measured on a continuous scale. More than half (54.37%) of the migrant street children and youth had lived in two or more places since migrating to the city. Multivariate negative binomial regression analysis reveals migrant street children and youth's intra-urban mobility to be associated with gender (aIRR = 0.71, 95%CI 0.53-0.96), sex work (aIRR = 1.38, 95%CI 1.01-1.88), a daily income of one USD or more (aIRR = 1.57, 95%CI 1.16-2.13) and duration of stay in the city (aIRR = 1.54, 95%CI 1.17-2.01). Other drivers of intra-urban mobility included availability of causal work, personal safety and affordability of rental costs. Our findings suggest the need for urban housing and health policies to take into account street children and youth's intra-urban mobility and its drivers. Future research on all drivers of street children and youth's intra-urban mobility and its linkage with their health outcomes is recommended.
| S-EPMC7891785 | biostudies-literature
Project description:Caesarean sections (CS) is the most common lifesaving surgeries for obstructed labour and other emergency obstetrical conditions. The WHO had recommended ideal rate for CS to be between 5% and 15%. The rate higher than 15% indicates overused other than lifesaving. Bangladesh has experienced a dramatic increase in CS delivery from 4% in 2004 to 23% in 2014. This increase is elevated by the several factors including maternal education, maternal request or elective CS, and by the urban richest population. However, little is known about the use CS by the urban poorest population. Therefore, the study aimed to examine and identify the factors associated with CS among the urban disadvantaged section of the population. A total of 1063 randomly chosen women aged 15-49 years from the population of 121,912 residing five-different slums were interviewed during November-December 2016. CS delivery was considered as outcome variable. Both bivariate and multivariable statistical analyses were carried-out. We performed logistic regression analyses to examine the net-effect of independent variables on outcome variable. Over 25% of total deliveries and 50% of facility-based deliveries were CS. The odds of CS delivery was 3.4-fold greater among better-off women than poorest. Women who had 4 + ANC checks-up during pregnancy had a 2-fold higher odds of CS delivery than women of ANC check-up. In private facilities, 76% of births were delivered as CS, followed by 51% in public facilities and 24% in NGO facilities. The likelihood of CS delivery in private facilities was 9.2-fold greater than NGO facilities after controlling for women socio-demographic, pregnancy and delivery characteristics. Thus, the high use of CS is largely associated with private facility, ANC visits and household wealth. Therefore, the Government of Bangladesh should take immediate actions by designing new policies and regulations to ensure CS for the lifesaving condition, not for financial gain.
| S-EPMC6558294 | biostudies-literature
Project description:BackgroundWhile the sanitation ladder is useful in analysing progressive improvements in sanitation, studies in Uganda have not indicated the sanitation barriers faced by the urban poor. There are various challenges in shared latrine use, cleaning and maintenance. Results from Kampala city indicate that, failure to clean and maintain sanitation infrastructure can lead to a reversal of the potential benefits that come with various sanitation facilities.MethodsA cross sectional qualitative study was conducted between March and May 2013. Data were collected through 18 focus group discussions (FGDs) held separately; one with women, men and youth respectively. We also used pictorial methods; in addition, 16 key informant interviews were conducted. Data were analysed using content thematic approach. Relevant quotations per thematic area were identified and have been used in the presentation of the results.ResultsWhether a shared sanitation facility was improved or not, it was abandoned once it was not properly used and cleaned. The problem of using shared latrines began with the lack of proper latrine training when people do not know how to squat on the latrine hole. The constrained access and security concerns, obscure paths that were filthy especially at night, lack of light in the latrine cubicle, raised latrines sometimes up to two metres above the ground, coupled with lack of cleaning and emptying the shared facilities only made a bad situation worse. In this way, open defecation gradually substituted use of the available sanitation facilities. This paper argues that, filthy latrines have the same net effect as crude open defection.ConclusionWhereas most sanitation campaigns are geared towards provision of improved sanitation infrastructure, these findings show that mere provision of infrastructure (improved or not) without adequate emphasis on proper use, cleaning and maintenance triggers an involuntary descent off the sanitation ladder. Understanding this reversal movement is critical in sustainable sanitation services and should be a concern for all actors.
| S-EPMC4071028 | biostudies-literature
Project description:BackgroundLeptospirosis has become an urban health problem as slum settlements have expanded worldwide. Efforts to identify interventions for urban leptospirosis have been hampered by the lack of population-based information on Leptospira transmission determinants. The aim of the study was to estimate the prevalence of Leptospira infection and identify risk factors for infection in the urban slum setting.Methods and findingsWe performed a community-based survey of 3,171 slum residents from Salvador, Brazil. Leptospira agglutinating antibodies were measured as a marker for prior infection. Poisson regression models evaluated the association between the presence of Leptospira antibodies and environmental attributes obtained from Geographical Information System surveys and indicators of socioeconomic status and exposures for individuals. Overall prevalence of Leptospira antibodies was 15.4% (95% confidence interval [CI], 14.0-16.8). Households of subjects with Leptospira antibodies clustered in squatter areas at the bottom of valleys. The risk of acquiring Leptospira antibodies was associated with household environmental factors such as residence in flood-risk regions with open sewers (prevalence ratio [PR] 1.42, 95% CI 1.14-1.75) and proximity to accumulated refuse (1.43, 1.04-1.88), sighting rats (1.32, 1.10-1.58), and the presence of chickens (1.26, 1.05-1.51). Furthermore, low income and black race (1.25, 1.03-1.50) were independent risk factors. An increase of US$1 per day in per capita household income was associated with an 11% (95% CI 5%-18%) decrease in infection risk.ConclusionsDeficiencies in the sanitation infrastructure where slum inhabitants reside were found to be environmental sources of Leptospira transmission. Even after controlling for environmental factors, differences in socioeconomic status contributed to the risk of Leptospira infection, indicating that effective prevention of leptospirosis may need to address the social factors that produce unequal health outcomes among slum residents, in addition to improving sanitation.
| S-EPMC2292260 | biostudies-literature
Project description:Managing urban flood risk is a key global challenge of the twenty-first century. Drivers of future UK flood risk were identified and assessed by the Flood Foresight project in 2002-2004 and 2008; envisaging flood risk during the 2050s and 2080s under a range of scenarios for climate change and socio-economic development. This paper qualitatively reassesses and updates these drivers, using empirical evidence and advances in flood risk science, technology and practice gained since 2008. Of the original drivers, five have strengthened, three have weakened and 14 remain within their 2008 uncertainty bands. Rainfall, as impacted by climate change, is the leading source driver of future urban flood risk. Intra-urban asset deterioration, leading to increases in a range of consequential flood risks, is the primary pathway driver. Social impacts (risk to life and health, and the intangible impacts of flooding on communities) and continued capital investment in buildings and contents (leading to greater losses when newer buildings of higher economic worth are inundated) have strengthened as receptor drivers of urban flood risk. Further, we propose two new drivers: loss of floodable urban spaces and indirect economic impacts, which we suggest may have significant impacts on future urban flood risk. This article is part of the theme issue 'Urban flood resilience'.
| S-EPMC7061970 | biostudies-literature
Project description:Global deaths from cardiovascular disease are increasing as a result of population growth, the aging of populations, and epidemiologic changes in disease. Disentangling the effects of these three drivers on trends in mortality is important for planning the future of the health care system and benchmarking progress toward the reduction of cardiovascular disease.We used mortality data from the Global Burden of Disease Study 2013, which includes data on 188 countries grouped into 21 world regions. We developed three counterfactual scenarios to represent the principal drivers of change in cardiovascular deaths (population growth alone, population growth and aging, and epidemiologic changes in disease) from 1990 to 2013. Secular trends and correlations with changes in national income were examined.Global deaths from cardiovascular disease increased by 41% between 1990 and 2013 despite a 39% decrease in age-specific death rates; this increase was driven by a 55% increase in mortality due to the aging of populations and a 25% increase due to population growth. The relative contributions of these drivers varied by region; only in Central Europe and Western Europe did the annual number of deaths from cardiovascular disease actually decline. Change in gross domestic product per capita was correlated with change in age-specific death rates only among upper-middle income countries, and this correlation was weak; there was no significant correlation elsewhere.The aging and growth of the population resulted in an increase in global cardiovascular deaths between 1990 and 2013, despite a decrease in age-specific death rates in most regions. Only Central and Western Europe had gains in cardiovascular health that were sufficient to offset these demographic forces. (Funded by the Bill and Melinda Gates Foundation and others.).
| S-EPMC4482354 | biostudies-literature
Project description:We study the spread of COVID-19 across neighbourhoods of cities in the developing world and find that small numbers of neighbourhoods account for a majority of cases (k-index approx. 0.7). We also find that the countrywide distribution of cases across states/provinces in these nations also displays similar inequality, indicating self-similarity across scales. Neighbourhoods with slums are found to contain the highest density of cases across all cities under consideration, revealing that slums constitute the most at-risk urban locations in this epidemic. We present a stochastic network model to study the spread of a respiratory epidemic through physically proximate and accidental daily human contacts in a city, and simulate outcomes for a city with two kinds of neighbourhoods-slum and non-slum. The model reproduces observed empirical outcomes for a broad set of parameter values-reflecting the potential validity of these findings for epidemic spread in general, especially across cities of the developing world. We also find that distribution of cases becomes less unequal as the epidemic runs its course, and that both peak and cumulative caseloads are worse for slum neighbourhoods than non-slums at the end of an epidemic. Large slums in the developing world, therefore, contain the most vulnerable populations in an outbreak, and the continuing growth of metropolises in Asia and Africa presents significant challenges for future respiratory outbreaks from perspectives of public health and socioeconomic equity.
| S-EPMC7879756 | biostudies-literature