Factors associated with differential seropositivity to Leptospira interrogans and Leptospira kirschneri in a high transmission urban setting for leptospirosis in Brazil

BACKGROUND

Leptospirosis is a zoonosis caused by pathogenic species of bacteria belonging to the genus Leptospira. Most studies infer the epidemiological patterns of a single serogroup or aggregate all serogroups to estimate overall seropositivity, thus not exploring the risks of exposure to distinct serogroups. The present study aims to delineate the demographic, socioeconomic and environmental factors associated with seropositivity of Leptospira serogroup Icterohaemorraghiae and serogroup Cynopteri in an urban high transmission setting for leptospirosis in Brazil.

METHODS/PRINCIPAL FINDINGS

We performed a cross-sectional serological study in five informal urban communities in the city of Salvador, Brazil. During the years 2018, 2020 2021, we recruited 2.808 residents and collected blood samples for serological analysis using microagglutination assays. We used a fixed-effect multinomial logistic regression model to identify risk factors associated with seropositivity for each serogroup. Seropositivity to Cynopteri increased with each year of age (OR 1.03; 95% CI 1.01-1.06) and was higher in those living in houses with unplastered walls (exposed brick) (OR 1.68; 95% CI 1.09-2.59) and where cats were present near the household (OR 2.00; 95% CI 1.03-3.88). Seropositivity to Icterohaemorrhagiae also increased with each year of age (OR 1.02; 95% CI 1.01-1.03) and was higher in males (OR 1.51; 95% CI 1.09-2.10), in those with work-related exposures (OR 1.71; 95% CI 1.10-2.66) or who had contact with sewage (OR 1.42; 95% CI 1.00-2.03). Spatial analysis showed differences in distribution of seropositivity to serogroups Icterohaemorrhagiae and Cynopteri within the five districts where study communities were situated.

CONCLUSIONS/SIGNIFICANCE

Our data suggest distinct epidemiological patterns associated with the Icterohaemorrhagiae and Cynopteri serogroups in the urban environment at high risk for leptospirosis and with differences in spatial niches. We emphasize the need for studies that accurately identify the different pathogenic serogroups that circulate and infect residents of low-income areas.

Bacterial MgSe complex nanoparticle synthesis and electrical characterization of fabricated Ag/MgSe/p-Si hetero-structure under dark and illumination

The Pseudomonas aeruginosa OG1 strain was used in the bacterial synthesis of MgSe compound nanoparticles. The obtained samples were subsequently shaped into nanocrystalline MgSe films, and their optical, structural, morphological, and electrical properties were assessed on glass and p-Si substrates. Structural and morphological characterizations showed that the fabricated thin film samples have a polycrystalline structure with high quality and uniform grain sizes. The MgSe films produced on glass substrates exhibit a direct spectral band gap of 2.53 eV, according to optical measurements. The Ag/MgSe/p-Si layered diode structure was fabricated using the produced MgSe nanoparticles and then characterized by electrical properties. Electrical measurements were carried out under these two conditions to assess the effects of dark and illumination conditions on the band dynamics of the heterostructure devices. Under illumination, the barrier height decreased while the interface density states distribution increased. These measurements showed that using bacterial-assisted grown MgSe nanocrystalline films, the developed Ag/MgSe/p-Si device structure exhibited a remarkable photoresponse and stable rectifying property. Green synthesis methods for the production of these nanocrystalline materials have the potential to offer low-cost alternatives for photosensitive applications.

Factors associated with differential seropositivity to Leptospira interrogans and Leptospira kirschneri in a high transmission urban setting for leptospirosis in Brazil

Background

Leptospirosis is a zoonosis caused by pathogenic species of bacteria belonging to the genus Leptospira. Most studies infer the epidemiological patterns of a single serogroup or aggregate all serogroups to estimate overall seropositivity, thus not exploring the risks of exposure to distinct serogroups. The present study aims to delineate the demographic, socioeconomic and environmental factors associated with seropositivity of Leptospira serogroup Icterohaemorraghiae and serogroup Cynopteri in an urban high transmission setting for leptospirosis in Brazil.

Methods/Principal Findings

We performed a cross-sectional serological study in five urban informal communities in the city of Salvador, Brazil. During the years 2018, 2020 2021, we recruited 2.808 residents and collected blood samples for serological analysis using microagglutination assays. We used a mixed-effect multinomial logistic regression model to identify risk factors associated with seropositivity for each serogroup. Seropositivity to Cynopteri increased with age in years (OR 1.03; 95% CI 1.01-1.06) and was higher in those living in houses with unplaster walls (exposed brick) (OR 1.68; 95% CI 1.09-2.59) and where cats were present near the household (OR 2.00; 95% CI 1.03-3.88). Seropositivity to Icterohaemorrhagiae also increased with age in years (OR 1.02; 95% CI 1.01-1.03) but was higher in males (OR 1.51; 95% CI 1.09-2.10), in those with work-related exposures (OR 1.71; 95% CI 1.10-2.66) or who had contact with sewage (OR 1.42; 95% CI 1.00-2.03). Spatial analysis showed differences in distribution of seropositivity to serogroups Icterohaemorrhagiae and Cynopteri within the five districts where study communities were situated.

Conclusions/Significance

Our data suggests distinct epidemiological patterns associated with serogroups Icterohaemorrhagiae and Cynopteri within the high-risk urban environment for leptospirosis and with differences of spatial niches. Future studies must identify the different pathogenic serogroups circulating in low-income areas, and further evaluate the potential role of cats in the transmission of the serogroup Cynopteri in urban settings.

A mechanical task for measuring sign- and goal-tracking in humans: A proof-of-concept study

Cue-based associative learning (i.e., Pavlovian conditioning) is a foundational component of behavior in almost all forms of animal life and may provide insight into individual differences in addiction liability. Cues can take on incentive-motivational properties (i.e., incentive salience) through Pavlovian learning. Extensive testing with non-human animals (primarily rats) has demonstrated significant variation among individuals in the behaviors this type of learning evokes. So-named "sign-trackers" and "goal-trackers" have been examined in many studies of non-human animals, but this work in humans is still a nascent area of research. In the present proof-of-concept study, we used a Pavlovian conditioned approach task to investigate human sign- and goal-tracking in emerging adults. Conditioned behaviors that developed over the course of the task were directed toward the reward-cue and toward the reward location. Participants' eye-gaze and behavior during the task were submitted to a latent profile analysis, which revealed three groups defined as sign-trackers (n = 10), goal-trackers (n = 4), and intermediate responders (n = 36). Impulsivity was a significant predictor of the sign-tracking group relative to the goal-tracking group. The present study provides preliminary evidence that a simple procedure can produce learned Pavlovian conditioned approach behavior in humans. Though further investigation is required, findings provide a promising step toward the long-term goal of translating important insights gleaned from basic research into treatment strategies that can be applied to clinical populations.

ANNUALIZED AND CUMULATIVE MEASURES OF ANTICHOLINERGIC EXPOSURE FOR RESEARCH AND CLINICAL APPLICATIONS

Medications with anticholinergic properties are commonly used by older adults despite being associated with dementia.The anticholinergic total standardized daily dose (TSDD) is a continuous measure of exposure that has been associated with an increased risk of dementia at values >1095 over ten years in epidemiologic studies. We sought to determine a cumulative (cTSDD) and annualized (aTSDD) in a sample of community-dwelling older adults enrolled in the ongoing Reducing Risk of Dementia Through Deprescribing (R2D2) trial (NCT04270474). Participants were 65 years or older without dementia, attended at least one primary care visit within 12 months prior to enrollment, and were current users of strong anticholinergics according to the 2012 Anticholinergic Cognitive Burden Scale. Prescribed and over-the-counter medication details were collected during the baseline visit through self-report and included strength, frequency, units/dose and duration. The aTSDD was calculated for each participant assuming continuous use patterns throughout the year. The cTSDD was calculated by summing the aTSDD across the number of years since initiation. Of 66 participants, the median cTSDD was 2425 (IQR 5131), and 48 (72%) exceeded the threshold of dementia risk (>1095). Additionally, the aTSDD had a median of 730 (IQR 547), with 60 (90%) exceeding the threshold of dementia risk (109.5, one-tenth of the ten-year risk) while 11 (17%) exceeded dementia risk threshold of 1095 considering 1 year of exposure. Both measures identified the majority of anticholinergic users exceeding dementia risk thresholds despite some disagreement between the two approaches. However, both methods have potential for research and clinical applications.

Why is leptospirosis hard to avoid for the impoverished? Deconstructing leptospirosis transmission risk and the drivers of knowledge, attitudes, and practices in a disadvantaged community in Salvador, Brazil

Several studies have identified socioeconomic and environmental risk factors for infectious disease, but the relationship between these and knowledge, attitudes, and practices (KAP), and more importantly their web of effects on individual infection risk, have not previously been evaluated. We conducted a cross-sectional KAP survey in an urban disadvantaged community in Salvador, Brazil, leveraging on simultaneously collected fine-scale environmental and epidemiological data on leptospirosis transmission. Residents' knowledge influenced their attitudes which influenced their practices. However, different KAP variables were driven by different socioeconomic and environmental factors; and while improved KAP variables reduced risk, there were additional effects of socioeconomic and environmental factors on risk. For example, males and those of lower socioeconomic status were at greater risk, but once we controlled for KAP, male gender and lower socioeconomic status themselves were not direct drivers of seropositivity. Employment was linked to better knowledge and a less contaminated environment, and hence lower risk, but being employed was independently associated with a higher, not lower risk of leptospirosis transmission, suggesting travel to work as a high risk activity. Our results show how such complex webs of influence can be disentangled. They indicate that public health messaging and interventions should take into account this complexity and prioritize factors that limit exposure and support appropriate prevention practices.

Population fluctuations and synanthropy explain transmission risk in rodent-borne zoonoses

Population fluctuations are widespread across the animal kingdom, especially in the order Rodentia, which includes many globally important reservoir species for zoonotic pathogens. The implications of these fluctuations for zoonotic spillover remain poorly understood. Here, we report a global empirical analysis of data describing the linkages between habitat use, population fluctuations and zoonotic reservoir status in rodents. Our quantitative synthesis is based on data collated from papers and databases. We show that the magnitude of population fluctuations combined with species' synanthropy and degree of human exploitation together distinguish most rodent reservoirs at a global scale, a result that was consistent across all pathogen types and pathogen transmission modes. Our spatial analyses identified hotspots of high transmission risk, including regions where reservoir species dominate the rodent community. Beyond rodents, these generalities inform our understanding of how natural and anthropogenic factors interact to increase the risk of zoonotic spillover in a rapidly changing world.

Linking rattiness, geography and environmental degradation to spillover Leptospira infections in marginalised urban settings: An eco-epidemiological community-based cohort study in Brazil

Background

Zoonotic spillover from animal reservoirs is responsible for a significant global public health burden, but the processes that promote spillover events are poorly understood in complex urban settings. Endemic transmission of Leptospira, the agent of leptospirosis, in marginalised urban communities occurs through human exposure to an environment contaminated by bacteria shed in the urine of the rat reservoir. However, it is unclear to what extent transmission is driven by variation in the distribution of rats or by the dispersal of bacteria in rainwater runoff and overflow from open sewer systems.

Methods

We conducted an eco-epidemiological study in a high-risk community in Salvador, Brazil, by prospectively following a cohort of 1401 residents to ascertain serological evidence for leptospiral infections. A concurrent rat ecology study was used to collect information on the fine-scale spatial distribution of 'rattiness', our proxy for rat abundance and exposure of interest. We developed and applied a novel geostatistical framework for joint spatial modelling of multiple indices of disease reservoir abundance and human infection risk.

Results

The estimated infection rate was 51.4 (95%CI 40.4, 64.2) infections per 1000 follow-up events. Infection risk increased with age until 30 years of age and was associated with male gender. Rattiness was positively associated with infection risk for residents across the entire study area, but this effect was stronger in higher elevation areas (OR 3.27 95% CI 1.68, 19.07) than in lower elevation areas (OR 1.14 95% CI 1.05, 1.53).

Conclusions

These findings suggest that, while frequent flooding events may disperse bacteria in regions of low elevation, environmental risk in higher elevation areas is more localised and directly driven by the distribution of local rat populations. The modelling framework developed may have broad applications in delineating complex animal-environment-human interactions during zoonotic spillover and identifying opportunities for public health intervention.

Funding

This work was supported by the Oswaldo Cruz Foundation and Secretariat of Health Surveillance, Brazilian Ministry of Health, the National Institutes of Health of the United States (grant numbers F31 AI114245, R01 AI052473, U01 AI088752, R01 TW009504 and R25 TW009338); the Wellcome Trust (102330/Z/13/Z), and by the Fundação de Amparo à Pesquisa do Estado da Bahia (FAPESB/JCB0020/2016). MTE was supported by a Medical Research UK doctorate studentship. FBS participated in this study under a FAPESB doctorate scholarship.

Evaluation of the impact of chemical control on the ecology of Rattus norvegicus of an urban community in Salvador, Brazil

BACKGROUND

The presence of synanthropic rodents, such as Rattus norvegicus, in urban environments generates high costs of prophylaxis and control, in large part due to the environmental transmission of the pathogenic spirochete Leptospira interrogans, which causes leptospirosis. In Salvador, Brazil, The Center for Control of Zoonosis (CCZ) is responsible for planning and implementing Rodent Control Programs (RCP) which are based on chemical rodenticide. However, these strategies have not been standardized for use in developing countries.

AIM

This study aimed to identify the effect of a chemical control campaign on the demographic variables of urban R. norvegicus, analyzing relative abundance, sex structure, body mass, and age of the population, as well as the characterization of spatial distribution among households, rodent capture campaigns and interventions.

METHODS

This study was carried out during 2015 in three valleys of an urban poor community in Salvador. Individuals of R. norvegicus were systematically captured before (Pre-intervention) and three months (1st post-intervention) and six months (2nd post-intervention) after a chemical control intervention conducted by the CCZ in two valleys of the study area while the third valley was not included in the intervention campaign and was used as a non-intervention reference. We used analysis of variance to determine if intervention affected demographic variables and chi-square to compare proportions of infested households (Rodent infestation index-PII).

RESULTS

During the chemical intervention, 939 households were visited. In the pre-intervention campaign, an effort of 310 trap nights resulted in 43 rodents captured, and in the 1st and 2nd, post-intervention campaigns resulted in 47 rodents captured over 312 trap nights and 36 rodents captured over 324 traps-nights, respectively. The rodent infestation index (PII) points did not show a reduction between the period before the intervention and the two periods after the chemical intervention (70%, 72%, and 65%, respectively). Regarding relative abundances, there was no difference between valleys and period before and two periods after chemical intervention (trap success valley 1: 0,18; 0,19; 0,18 / Valley 3 0,15; 0,17; 0,13/ P>0,05). Other demographic results showed that there was no difference in demographic characteristics of the rodent population before and after the intervention, as well as there being no influence of the application of rodenticide on the areas of concentration of capture of rodents between the campaigns.

CONCLUSION

Our study indicates that the chemical control was not effective in controlling the population of R. norvegicus and provides evidence of the need for re-evaluation of rodent control practices in urban poor community settings.

Population dynamics of synanthropic rodents after a chemical and infrastructural intervention in an urban low-income community

Synanthropic rodents are ubiquitous in low-income communities and pose risks for human health, as they are generally resistant to control programs. However, few or no studies have evaluated the long-term effect of chemical and infrastructural interventions on rodent population dynamics, especially in urban low-income communities, or evaluated the potential recovery of their population following interventions. We conducted a longitudinal study in a low-income community in the city of Salvador (BA, Brazil) to characterize the effect of interventions (chemical and infrastructural) on the dynamics of rodent population, and documented the post-intervention recovery of their population. We evaluated the degree of rodent infestation in 117 households/sampling points over three years (2014-2017), using tracking plates, a proxy for rodent abundance/activity. We reported a significant lower rodent activity/abundance after the chemical and infrastructural interventions (Z = -4.691 (p < 0.001)), with track plate positivity decreasing to 28% from 70% after and before interventions respectively. Therefore, the combination of chemical and infrastructural interventions significantly decreased the degree of rodent infestation in the study area. In addition, no rodent population rebound was recorded until almost a year post-intervention, and the post-intervention infestation level did not attain the pre-intervention level all through the study. Moreover, among pre-treatment conditions, access to sewer rather than the availability of food was the variable most closely associated with household rodent infestation. Our study indicates that Integrated Pest Management (IPM)-approaches are more effective in reducing rodent infestation than the use of a single method. Our findings will be useful in providing guidance for long-term rodent control programs, especially in urban low-income communities.

Differentiating between Evidence/gap maps and scoping reviews in the evidence synthesis ecosystem

OBJECTIVE

Scoping reviews and evidence map methodologies are increasingly used by researchers. The objective of this article is to outline the main differences between both types of evidence synthesis to improve their conduct.

STUDY DESIGN AND SETTING

This article summarizes the key issues facing reviewers who conduct scoping reviews and evidence maps and those who use the results and may engage in consultations during their development.

RESULTS

Several differences exist between the methodologies, and these are in their protocol development, scope, inclusion criteria, data extraction, reporting, and use. Evidence maps are mainly driven by questions of effectiveness of a particular intervention and hence they use the PICOS format similar to systematic reviews of effectiveness. Scoping reviews mostly use the PCC format where they map a concept of interest relevant to a particular population in a specific setting and context. Data extraction is limited by only coding of studies and intervention characteristics in evidence maps. The results of the evidence maps can be used inform research priorities and research funding, whereas scoping reviews results may be used to inform policy development by clarifying key concepts and methods, and further research.

CONCLUSION

We recommend authors who are planning to undertake scoping reviews confirm that their research question can be appropriately answered using a scoping review methodology, however, for broader research questions without the need for an in-depth analysis of the information, we recommend authors to consider mapping reviews.

Puumala Orthohantavirus Infection Does Not Affect the Trapping Success of Its Reservoir Host

Pathogens might affect behavior of infected reservoir hosts and hence their trappability, which could bias population estimates of pathogen prevalence. In this study, we used snap-trapping data on Puumala orthohantavirus (PUUV)-infected (n = 1619) and noninfected (n = 6940) bank voles (Myodes glareolus) from five vole cycles, normally representing increase, peak, and decline phase, to evaluate if infection status affected trapping success. If PUUV infection, as previously suggested, increases activity and/or mobility, we would expect a higher proportion of infected than noninfected specimens in the first trapping night. However, the proportion of PUUV-infected voles did not differ across the three trapping nights. We conclude that PUUV infection did not affect trapping success, confirming snap trapping as an appropriate trapping method for studies on PUUV prevalence and likely other orthohantaviruses.

Climate change accelerates winter transmission of a zoonotic pathogen

Many zoonotic diseases are weather sensitive, raising concern how their distribution and outbreaks will be affected by climate change. At northern high latitudes, the effect of global warming on especially winter conditions is strong. By using long term monitoring data (1980-1986 and 2003-2013) from Northern Europe on temperature, precipitation, an endemic zoonotic pathogen (Puumala orthohantavirus, PUUV) and its reservoir host (the bank vole, Myodes glareolus), we show that early winters have become increasingly wet, with a knock-on effect on pathogen transmission in its reservoir host population. Further, our study is the first to show a climate change effect on an endemic northern zoonosis, that is not induced by increased host abundance or distribution, demonstrating that climate change can also alter transmission intensity within host populations. Our results suggest that rainy early winters accelerate PUUV transmission in bank voles in winter, likely increasing the human zoonotic risk in the North.

Demographic drivers of Norway rat populations from urban slums in Brazil

The Norway rat is a globally distributed pest, known for its resilience to eradication and control programs. Efficient population control, especially in urban settings, is dependent on knowledge of rat demography and population ecology. We analyzed the relationship between four demographic outcomes, estimated by live-trapping data, and fine-scale environmental features measured at the capture site. Wounds, a proxy for agonistic interactions, were associated with mature individuals. Areas with environmental features favorable to rats, such as open sewers and unpaved earth, were associated with more mature individuals with a better body condition index. The control measures (environmental stressors) are likely to be disrupting the social structure of rat colonies, increasing the frequency and distribution of agonistic interactions, which were common in both sexes and maturity states. The relationship between the favorable environmental conditions and the demographic markers analyzed indicate possible targets for infestation control through environmental manipulation, and could be incorporated into current pest management programs to achieve long-term success. Our study indicate that urban interventions focused on removal of potential resources for rats could be potential long-term solutions by reducing the carrying capacity of the environment.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11252-020-01075-2.

Statistical optimization of amorphous iron phosphate: inorganic sol-gel synthesis-sodium potential insertion

Iron phosphate, Fe₂ (HPO₄)₃*4H₂O, is synthesized at ambient temperature, using the inorganic sol–gel method coupled to the microwave route. The experimental conditions for the gelling of Fe (III)-H₃PO₄ system are previously defined. Potentiometric Time Titration (PTT) and Potentiometric Mass Titration (PMT) investigate the acid–base surface chemistry of obtained phosphate. Variations of surface charge with the contact time, Q a function of T, are examined for time contact varying in the range 0–72 h. The mass suspensions used for this purpose are 0.75, 1.25 and 2.5 g L⁻¹. The point of zero charge (PZC) and isoelectric point (IEP) are defined using the derivative method examining the variations \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\frac{{{\text{dpH}}}}{{{\text{d}}t}} = f\left( {{\text{pH}}} \right)$$\end{document}dpHdt=fpH, at lower contact time. A shift is observed for PZC and IEP towards low values that are found to be 2.2 ± 0.2 and 1.8 ± 0.1, respectively. In acidic conditions, the surface charge behavior of synthesized phosphate is dominated by \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\overline{{ > {\text{POH}}}}$$\end{document}>POH¯ group which pK_a = 2.45 ± 0.15. Q against T titration method is performed for synthesized Fe₂ (HPO₄)₃*4H₂O in NaCl electrolytes. The maximal surface charge (Q) is achieved at the low solid suspension. Hence, for m = 0.75 g L⁻¹, Q value of 50 coulombs is carried at μ = 0.1 and pH around 12, while charge value around 22 coulombs is reached in the pH range: 3–10. The effect of activation time, Q and pH on sodium insertion in iron phosphate, were fully evaluated. To determine the optimal conditions of the studied process, mathematical models are used develop response surfaces in order to characterize the most significant sodium interactions according to the variation of the pH, Q, the contact time and the contents of the synthesized material.

Prevalence of Orthohantavirus-Reactive Antibodies in Humans and Peri-Domestic Rodents in Northern Ethiopia

In 2012, Tigray orthohantavirus was discovered in Ethiopia, but its seasonal infection in small mammals, and whether it poses a risk to humans was unknown. The occurrence of small mammals, rodents and shrews, in human inhabitations in northern Ethiopia is affected by season and presence of stone bunds. We sampled small mammals in two seasons from low- and high-density stone bund fields adjacent to houses and community-protected semi-natural habitats in Atsbi and Hagere Selam, where Tigray orthohantavirus was first discovered. We collected blood samples from both small mammals and residents using filter paper. The presence of orthohantavirus-reactive antibodies in blood was then analyzed using immunofluorescence assay (human samples) and enzyme linked immunosorbent assays (small mammal samples) with Puumala orthohantavirus as antigen. Viral RNA was detected by RT-PCR using small mammal blood samples. Total orthohantavirus prevalence (antibodies or virus RNA) in the small mammals was 3.37%. The positive animals were three Stenocephalemys albipes rats (prevalence in this species = 13.04%). The low prevalence made it impossible to determine whether season and stone bunds were associated with orthohantavirus prevalence in the small mammals. In humans, we report the first detection of orthohantavirus-reactive IgG antibodies in Ethiopia (seroprevalence = 5.26%). S. albipes lives in close proximity to humans, likely increasing the risk of zoonotic transmission.

Prevalence of Diarrheagenic Escherichia coli (DEC) and Salmonella spp. with zoonotic potential in urban rats in Salvador, Brazil

Studies evaluating the occurrence of enteropathogenic bacteria in urban rats (Rattus spp.) are scarce worldwide, specifically in the urban environments of tropical countries. This study aims to estimate the prevalence of diarrhoeagenic Escherichia coli (DEC) and Salmonella spp. with zoonotic potential in urban slum environments. We trapped rats between April and June 2018 in Salvador, Brazil. We collected rectal swabs from Rattus spp., and cultured for E. coli and Salmonella spp., and screened E. coli isolates by polymerase chain reaction to identify pathotypes. E. coli were found in 70% of Rattus norvegicus and were found in four Rattus rattus. DEC were isolated in 31.3% of the 67 brown rats (R. norvegicus). The pathotypes detected more frequently were shiga toxin E. coli in 11.9%, followed by atypical enteropathogenic E. coli in 10.4% and enteroinvasive E. coli in 4.5%. From the five black rats (R. rattus), two presented DEC. Salmonella enterica was found in only one (1.4%) of 67 R. norvegicus. Our findings indicate that both R. norvegicus and R. rattus are host of DEC and, at lower prevalence, S. enterica, highlighting the importance of rodents as potential sources of pathogenic agents for humans.

A multivariate geostatistical framework for combining multiple indices of abundance for disease vectors and reservoirs: a case study of rattiness in a low-income urban Brazilian community

A key requirement in studies of endemic vector-borne or zoonotic disease is an estimate of the spatial variation in vector or reservoir host abundance. For many vector species, multiple indices of abundance are available, but current approaches to choosing between or combining these indices do not fully exploit the potential inferential benefits that might accrue from modelling their joint spatial distribution. Here, we develop a class of multivariate generalized linear geostatistical models for multiple indices of abundance. We illustrate this novel methodology with a case study on Norway rats in a low-income urban Brazilian community, where rat abundance is a likely risk factor for human leptospirosis. We combine three indices of rat abundance to draw predictive inferences on a spatially continuous latent process, rattiness, that acts as a proxy for abundance. We show how to explore the association between rattiness and spatially varying environmental factors, evaluate the relative importance of each of the three contributing indices and assess the presence of residual, unexplained spatial variation, and identify rattiness hotspots. The proposed methodology is applicable more generally as a tool for understanding the role of vector or reservoir host abundance in predicting spatial variation in the risk of human disease.

Extracting Arabic Composite Names Using Genitive Principles of Arabic Grammar

Named Entity Recognition (NER) is a basic prerequisite of using Natural Language Processing (NLP) for information retrieval. Arabic NER is especially challenging as the language is morphologically rich and has short vowels with no capitalisation convention. This article presents a novel rule-based approach that uses linguistic grammar-based techniques to extract Arabic composite names from Arabic text. Our approach uniquely exploits the genitive Arabic grammar rules; in particular, the rules regarding the identification of definite nouns (معرفة) and indefinite nouns (نكرة) to support the process of extracting composite names. Based on domain knowledge and Arabic Genitive Rules (AGR), the developed approach formalises a set of syntactical rules and linguistic patterns that initially use genitive patterns to classify definiteness within phrases and then extracts proper composite names from the unstructured text. The developed novel approach does not place any constraints on the length of the Arabic composite name and our initial experimentation demonstrated high recall and precision results when the NER algorithm was applied to a financial domain corpus.

Selective Predation by Owls on Infected Bank Voles (Myodes glareolus) as a Possible Sentinel of Tularemia Outbreaks

Tularemia is a widely spread zoonotic disease in the northern hemisphere, caused by the bacterium Francisella tularensis. In humans, tularemia is an acute febrile illness with incidence peaks in late summer to early autumn of outbreak years, but there is no early warning system in place that can reduce the impact of disease by providing timely risk information. In this study, we revisit previously unpublished data on F. tularensis in water, sediment, soil, and small mammals from 1984 in northern Sweden. In addition, we used human case data from the national surveillance system for tularemia in the same year. In the environmental and small mammal material, bank vole (Myodes glareolus) samples from urine and bladder were the only samples that tested positive for F. tularensis. The prevalence of F. tularensis among trapped bank voles was 13.5%, although all six bank voles that were retrieved from owl nest boxes in early May tested positive. Forty-two human tularemia cases were reported from August to December in 1984. Based on these results, we encourage investigating the potential role of tularemia-infected bank voles retrieved from owl nest boxes in spring as an early warning for outbreaks of tularemia among humans in summer and autumn of the same year.

Adverse drug reactions in primary care: a scoping review

BACKGROUND

Medication-related adverse events, or adverse drug reactions (ADRs) are harmful events caused by medication. ADRs could have profound effects on the patients' quality of life, as well as creating an increased burden on the healthcare system. ADRs are one of the rising causes of morbidity and mortality internationally, and will continue to be a significant public health issue with the increased complexity in medication, to treat various diseases in an aging society. This scoping review aims to provide a detailed map of the most common adverse drug reactions experienced in primary healthcare setting, the drug classes that are most commonly associated with different levels/types of adverse drug reactions, causes of ADRs, their prevalence and consequences of experiencing ADRs.

METHODS

We systematically reviewed electronic databases Ovid MEDLINE, Embase, CINAHL Plus, Cochrane Central Register of Controlled Trials, PsycINFO and Scopus. In addition, the National Patient Safety Foundation Bibliography and the Agency for Health Care Research and Quality and Patient Safety Net Bibliography were searched. Studies published from 1990 onwards until December 7, 2018 were included as the incidence of reporting drug reactions were not prevalent before 1990. We only include studies published in English.

RESULTS

The final search yielded a total of 19 citations for inclusion published over a 15-year period that primarily focused on investigating the different types of adverse drug reactions in primary healthcare. The most causes of adverse events were related to drug related and allergies. Idiosyncratic adverse reactions were not very commonly reported. The most common adverse drug reactions reported in the studies included in this review were those that are associated with the central nervous system, gastrointestinal system and cardiovascular system. Several classes of medications were reported to be associated with adverse events.

CONCLUSION

This scoping review identified that the most causes of ADRs were drug related and due to allergies. Idiosyncratic adverse reactions were not very commonly reported in the literature. This is mainly because it is hard to predict and these reactions are not associated with drug doses or routes of administration. The most common ADRs reported in the studies included in this review were those that are associated with the central nervous system, gastrointestinal system and cardiovascular system. Several classes of medications were reported to be associated with ADRs.

Wildfire-induced short-term changes in a small mammal community increase prevalence of a zoonotic pathogen?

Natural disturbances like droughts and fires are important determinants of wildlife community structure and are suggested to have important implications for prevalence of wildlife-borne pathogens. After a major wildfire affecting >1,600 ha of boreal forest in Sweden in 2006, we took the rare opportunity to study the short-term response (2007-2010 and 2015) of small mammal community structure, population dynamics, and prevalence of the Puumala orthohantavirus (PUUV) hosted by bank voles (Myodes glareolus). We performed snap-trapping in permanent trapping plots in clear-cuts (n = 3), unburnt reference forests (n = 7), and the fire area (n = 7) and surveyed vegetation and habitat structure. Small mammal species richness was low in all habitats (at maximum three species per trapping session), and the bank vole was the only small mammal species encountered in the fire area after the first postfire year. In autumns of years of peak rodent densities, the trapping index of bank voles was lowest in the fire area, and in two of three peak-density years, it was highest in clear-cuts. Age structure of bank voles varied among forest types with dominance of overwintered breeders in the fire area in the first postfire spring. PUUV infection probability in bank voles was positively related to vole age. Infection probability was highest in the fire area due to low habitat complexity in burnt forests, which possibly increased encounter rate among bank voles. Our results suggest that forest fires induce cascading effects, including fast recovery/recolonization of fire areas by generalists like bank voles, impoverished species richness of small mammals, and altered prevalence of a rodent-borne zoonotic pathogen. Our pilot study suggests high human infection risk upon encountering a bank vole in the fire area, however, with even higher overall risk in unburnt forests due to their higher vole numbers.

OPEN RESEARCH BADGES

This article has earned an Open Data Badge for making publicly available the digitally-shareable data necessary to reproduce the reported results. The data is available at https://osf.io/6fsy3/.

Population Dynamics of Bank Voles Predicts Human Puumala Hantavirus Risk

Predicting risk of zoonotic diseases, i.e., diseases shared by humans and animals, is often complicated by the population ecology of wildlife host(s). We here demonstrate how ecological knowledge of a disease system can be used for early prediction of human risk using Puumala hantavirus (PUUV) in bank voles (Myodes glareolus), which causes Nephropathia epidemica (NE) in humans, as a model system. Bank vole populations at northern latitudes exhibit multiannual fluctuations in density and spatial distribution, a phenomenon that has been studied extensively. Nevertheless, existing studies predict NE incidence only a few months before an outbreak. We used a time series on cyclic bank vole population density (1972-2013), their PUUV infection rates (1979-1986; 2003-2013), and NE incidence in Sweden (1990-2013). Depending on the relationship between vole density and infection prevalence (proportion of infected animals), either overall density of bank voles or the density of infected bank voles may be used to predict seasonal NE incidence. The density and spatial distribution of voles at density minima of a population cycle contribute to the early warning of NE risk later at its cyclic peak. When bank voles remain relatively widespread in the landscape during cyclic minima, PUUV can spread from a high baseline during a cycle, culminating in high prevalence in bank voles and potentially high NE risk during peak densities.

Two-year patient-related outcome measures (PROM) of primary ventral and incisional hernia repair using a novel three-dimensional composite polyester monofilament mesh: the SymCHro registry study

Purpose

This study examined patient-related outcome measures (PROMs) after repair of ventral primary or incisional hernias using Symbotex™ composite mesh (SCM), a novel three-dimensional collagen-coated monofilament polyester textile.

Methods

Pre-operative, peri-operative, and post-operative data were obtained from the French “Club Hernie” registry with 12- and 24-month follow-up.

Results

One-hundred consecutive patients (mean age 62.0 ± 13.7; 51% female) underwent repair of 105 hernias: primary (39/105, 37.1%, defect area 5.2 ± 5.6 cm²) and incisional (66/105, 62.9%, 31.9 ± 38.7.8 cm²). The mean BMI was 29.7 (± 5.6 kg/m²). American Society of Anesthesiologists classifications were I 39.4%, II 37.4% and III 23.2%. 75% had risk factors for healing and/or dissection. Of 38 primary repairs, 37 were completed laparoscopically (combined approach n = 1), and of 62 incisional hernia repairs, 40 were completed laparoscopically, and 20 by open repair (combined approach n = 2). Laparoscopic was quicker than open repair (36.2 ± 23.5 min vs. 67.4 ± 25.8, p < 0001). Before surgery, 86.3% of hernias were reported to cause discomfort/pain or dysesthesia. At 24 months (93 of 100 patients), 91 (97.8%) reported no lump and 81 (87.1%) no pain or discomfort. Of 91 patients, 86 (94.5%) rated their repair “good” or “excellent.” There were nine non-serious, surgeon-detected adverse events (ileus, n = 3; seroma, n = 6) and one hernia recurrence (6–12 months).

Conclusions

Compared to baseline, open and laparoscopic surgery improved PROMs 24 months after primary and incisional hernia repair. Minimal complications and recurrence support the long-term efficacy of SCM.

Childhood central adiposity at ages 5 and 9 shows consistent relationship with that of the maternal grandmother but not other grandparents

BACKGROUND

The importance of a life course approach to childhood obesity has been emphasized; however, few studies can prospectively investigate relationships in three-generation families.

OBJECTIVE

To prospectively investigate the relationship between grandparental and grandchild waist circumference (WC) at ages 5 and 9 down maternal and paternal lines.

METHODS

At baseline in the Lifeways Cross-Generation Cohort, 1094 children were born to 1082 mothers; 585 were examined at age 5 and 298 at age 9. Of the total 589 children with measured WC, data were also available from 745 grandparents. Child WC was standardized for age and sex, and theory-based hierarchical linear regression was used.

RESULTS

Maternal grandmother (MGM) WC was predictive of grandchild WC at both time points. At age 5, grandchild's standardized birth weight (B = 0.266, p = 0.001), mother's means tested eligibility for free medical care (B = 1.029, p = 0.001) and grandchild seeing maternal grandparents daily (B = 0.312, p = 0.048) were significant alongside MGM WC (B = 0.015, p = 0.019). At age 9, only MGM WC (B = 0.022, p = 0.033) and mother's WC (B = 0.032, p = 0.005) were significant. Mediation analysis with mother's WC showed significant direct relationship of MGM and grandchild WC.

CONCLUSIONS

This prospective cross-generational cohort shows consistent patterns of association between MGM and grandchild WC, not seen in other grandparental lineages.

Diabetes microvascular complications-A clinical update

BACKGROUND

The purpose of this study is to summarise the empirical evidence addressing diabetes microvascular complications and management. The effects of diabetes mellitus include long-term damage, dysfunction and failure of various organs. Microvascular disease tends to occur predominantly in tissues where glucose uptake is independent of insulin activity because these tissues are exposed to glucose levels that correlate very closely with blood glucose levels. These metabolic injuries cause altered blood flow and changes in endothelial permeability, extravascular protein deposition and coagulation resulting in organ dysfunction which in turn lead to microvascular complications.

METHOD

A systematic search of the literature from 2000 to 2016 was conducted using four databases (Medline, Pubmed, Cochrane central and Google scholar) using search terms such as diabetic microvascular complications', pathogenesis, screening, risk factors, pharmacological and non-pharmacological interventions and management.

RESULTS

The current evidence supports a direct relationship between blood pressure (BP) and glycaemic control and progression of nephropathy and retinopathy. These are now considered as independent risk factors for microvascular disease progression. New fields of research addressing new drugs as potential therapeutic targets of the future will be presented.

CONCLUSION

The prevention of microvascular disease involves paying attention to aggravating risk factors and implementing screening programmes to improve early detection.

Spatial prediction and validation of zoonotic hazard through micro-habitat properties: where does Puumala hantavirus hole - up?

Background

To predict the risk of infectious diseases originating in wildlife, it is important to identify habitats that allow the co-occurrence of pathogens and their hosts. Puumala hantavirus (PUUV) is a directly-transmitted RNA virus that causes hemorrhagic fever in humans, and is carried and transmitted by the bank vole (Myodes glareolus). In northern Sweden, bank voles undergo 3–4 year population cycles, during which their spatial distribution varies greatly.

Methods

We used boosted regression trees; a technique inspired by machine learning, on a 10 – year time-series (fall 2003–2013) to develop a spatial predictive model assessing seasonal PUUV hazard using micro-habitat variables in a landscape heavily modified by forestry. We validated the models in an independent study area approx. 200 km away by predicting seasonal presence of infected bank voles in a five-year-period (2007–2010 and 2015).

Results

The distribution of PUUV-infected voles varied seasonally and inter-annually. In spring, micro-habitat variables related to cover and food availability in forests predicted both bank vole and infected bank vole presence. In fall, the presence of PUUV-infected voles was generally restricted to spruce forests where cover was abundant, despite the broad landscape distribution of bank voles in general. We hypothesize that the discrepancy in distribution between infected and uninfected hosts in fall, was related to higher survival of PUUV and/or PUUV-infected voles in the environment, especially where cover is plentiful.

Conclusions

Moist and mesic old spruce forests, with abundant cover such as large holes and bilberry shrubs, also providing food, were most likely to harbor infected bank voles. The models developed using long-term and spatially extensive data can be extrapolated to other areas in northern Fennoscandia. To predict the hazard of directly transmitted zoonoses in areas with unknown risk status, models based on micro-habitat variables and developed through machine learning techniques in well-studied systems, could be used.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-017-2618-z) contains supplementary material, which is available to authorized users.

Dampening of population cycles in voles affects small mammal community structure, decreases diversity, and increases prevalence of a zoonotic disease

Long-term decline and depression of density in cyclic small rodents is a recent widespread phenomenon. These observed changes at the population level might have cascading effects at the ecosystem level. Here, we assessed relationships between changing boreal landscapes and biodiversity changes of small mammal communities. We also inferred potential effects of observed community changes for increased transmission risk of Puumala virus (PUUV) spread, causing the zoonotic disease nephropatica epidemica in humans. Analyses were based on long-term (1971-2013) monitoring data of shrews and voles representing 58 time series in northern Sweden. We calculated richness, diversity, and evenness at alpha, beta, and gamma level, partitioned beta diversity into turnover (species replacement) and nestedness (species addition/removal), used similarity percentages (SIMPER) analysis to assess community structure, and calculated the cumulated number of PUUV-infected bank voles and average PUUV prevalence (percentage of infected bank voles) per vole cycle. Alpha, beta, and gamma richness and diversity of voles, but not shrews, showed long-term trends that varied spatially. The observed patterns were associated with an increase in community contribution of bank vole (Myodes glareolus), a decrease of gray-sided vole (M. rufocanus) and field vole (Microtus agrestis) and a hump-shaped variation in contribution of common shrew (Sorex araneus). Long-term biodiversity changes were largely related to changes in forest landscape structure. Number of PUUV-infected bank voles in spring was negatively related to beta and gamma diversity, and positively related to turnover of shrews (replaced by voles) and to community contribution of bank voles. The latter was also positively related to average PUUV prevalence in spring. We showed that long-term changes in the boreal landscape contributed to explain the decrease in biodiversity and the change in structure of small mammal communities. In addition, our results suggest decrease in small mammal diversity to have knock-on effects on dynamics of infectious diseases among small mammals with potential implications for disease transmission to humans.

Total HDL cholesterol efflux capacity in healthy children - Associations with adiposity and dietary intakes of mother and child

BACKGROUND AND AIMS

High-density lipoprotein (HDL) cholesterol efflux capacity in adults may be a measure of the atheroprotective property of HDL. Little however, is known about HDL cholesterol efflux capacity in childhood. We aimed to investigate the relationship between HDL cholesterol efflux capacity and childhood anthropometrics in a longitudinal study.

METHODS AND RESULTS

Seventy-five children (mean age = 9.4 ± 0.4 years) were followed from birth until the age of 9 years. HDL cholesterol efflux capacity was determined at age 9 by incubating serum-derived HDL-supernatants with ³H-cholesterol labeled J774 macrophages and percentage efflux determined. Mothers provided dietary information by completing food frequency questionnaires in early pregnancy and then 5 years later on behalf of themselves and their children. Pearson's correlations and multiple regression analyses were conducted to confirm independent associations with HDL efflux. There was a negative correlation between HDL cholesterol efflux capacity and waist circumference at age 5 (r = -0.3, p = 0.01) and age 9 (r = -0.24, p = 0.04) and BMI at age 5 (r = -0.45, p = 0.01) and age 9 (r = -0.19, p = 0.1). Multiple regression analysis showed that BMI at age 5 remained significantly associated with reduced HDL cholesterol efflux capacity (r = -0.45, p < 0.001). HDL-C was negatively correlated with energy-adjusted fat intake (r = -0.24, p = 0.04) and positively correlated with energy-adjusted protein (r = 0.24, p = 0.04) and starch (r = 0.29, p = 0.01) intakes during pregnancy. HDL-C was not significantly correlated with children dietary intake at age 5. There were no significant correlations between maternal or children dietary intake and HDL cholesterol efflux capacity.

CONCLUSIONS

This novel analysis shows that efflux capacity is negatively associated with adiposity in early childhood independent of HDL-C.