Estimate Infection Risk Research Articles

Modification of host social networks by manipulative parasites

Abstract Social network models provide a powerful tool to estimate infection risk for individual hosts and track parasite transmission through host populations. Here, bringing together concepts from social network theory, animal personality, and parasite manipulation of host behaviour, I argue that not only are social networks shaping parasite transmission, but parasites in turn shape social networks through their effects on the behaviour of infected individuals. Firstly, I review five general categories of behaviour (mating behaviour, aggressiveness, activity levels, spatial distribution, and group formation) that are closely tied to social networks, and provide evidence that parasites can affect all of them. Secondly, I describe scenarios in which behaviour-altering parasites can modify either the role or position of individual hosts within their social network, or various structural properties (e.g., connectance, modularity) of the entire network. Experimental approaches allowing comparisons of social networks pre- versus post-infection are a promising avenue to explore the feedback loop between social networks and parasite infections.

Direct potable reuse microbial risk assessment methodology: Sensitivity analysis and application to State log credit allocations

Understanding pathogen risks is a critically important consideration in the design of water treatment, particularly for potable reuse projects. As an extension to our published microbial risk assessment methodology to estimate infection risks associated with Direct Potable Reuse (DPR) treatment train unit process combinations, herein, we (1) provide an updated compilation of pathogen density data in raw wastewater and dose-response models; (2) conduct a series of sensitivity analyses to consider potential risk implications using updated data; (3) evaluate the risks associated with log credit allocations in the United States; and (4) identify reference pathogen reductions needed to consistently meet currently applied benchmark risk levels. Sensitivity analyses illustrated changes in cumulative annual risks estimates, the significance of which depends on the pathogen group driving the risk for a given treatment train. For example, updates to norovirus (NoV) raw wastewater values and use of a NoV dose-response approach, capturing the full range of uncertainty, increased risks associated with one of the treatment trains evaluated, but not the other. Additionally, compared to traditional log-credit allocation approaches, our results indicate that the risk methodology provides more nuanced information about how consistently public health benchmarks are achieved. Our results indicate that viruses need to be reduced by 14 logs or more to consistently achieve currently applied benchmark levels of protection associated with DPR. The refined methodology, updated model inputs, and log credit allocation comparisons will be useful to regulators considering DPR projects and design engineers as they consider which unit treatment processes should be employed for particular projects.

Development of a surgical site infection prediction model in orthopaedic trauma: The Denver Health Model

BackgroundThe CDC’s National Healthcare Safety Network’s (NHSN) current risk adjustment model for surgical site infections (SSI) following open reduction internal fixation (ORIF) of long bone fractures is a suboptimal predictor of risk. We hypothesized that by including variables known to be associated with SSI following ORIF, we would develop a model that would increase the accuracy and predictability of SSI risk. MethodsPatients who underwent ORIF of a long bone between January 1, 2012 and December 31, 2014 were included in the study (n=1543). Patient risk factors, injury risk factors and perioperative risk factors were considered in the development of this model. We developed a risk prediction model for SSI following ORIF and then applied this to a new dataset of ORIF to determine the expected number of infections. This was compared to the expected number of infections calculated using the NHSN risk adjusted model. ResultsThe final multivariate model included age (odds ratio: 1.02, p-value<0.001, 95% confidence interval: 1.00–1.04), lower leg fracture (2.63, 0.004, 1.40–4.93), open fracture (1.87, 0.07, 0.93–3.76), American Society of Anesthesiologists (ASA) (2.09, 0.02, 1.07–4.08) and history of methicillin-resistant Staphylococcus aureus (MRSA), which was the most important predictor of infection (7.20, <0.001, 2.61–19.85). The c-index was 0.74 compared to 0.65 for the NHSN model, indicating that our model more accurate in estimating infection risk. When the developed model was used to predict the number of expected infections on a new dataset from 2015, 36.3 SSI were expected compared to 5.7 calculated by the NHSN model. ConclusionsThe model that was developed uses five easily identifiable risk factors that result in a more accurate prediction of infection at our facility than the currently used model.Level of evidence: Prognostic and epidemiologic study, level III.

The refined ABCD assessment and non-costly laboratory parameters are outcome predictors in acute exacerbation of COPD

BackgroundAcute exacerbation of chronic obstructive pulmonary disease (AECOPD) is common problem in clinical practice. Despite relatively new infection markers such as procalcitonin, copeptin and endothelin-1 revealed promising results in the estimation of infection risk and outcome prediction, their use is notably limited by factors as cost, availability and validation. So in the low income countries, it is advisable to re-explore the value of the inexpensive investigations. ObjectivesOur study primarily aimed at more validation of the updated GOLD grouping of COPD by evaluating its prognostic role during AECOPD. In addition, in the search for a non-invasive and easily measurable laboratory parameter that might reflect systemic inflammation, we investigated the role of Neutrophil Lymphocyte ratio (NLR) and Thrombocytopenia (TP) in predicting un-favorable outcome. MethodsThis study enrolled 80 patients with a diagnosis of COPD exacerbation admitted to the inpatient chest department, Sohag University hospital. Complete blood count (CBC), erythrocyte sedimentation rate (ESR), random blood glucose, serum creatinine and arterial blood gases were done within 2h of hospital admission. ABCD assessment and Severity of airflow limitation were determined. ResultsNeutrophil Lymphocyte ratio (NLR), Blood glucose, serum creatinine, Partial pressure of carbon dioxide, ESR, airflow limitation severity and length of stay (LOS) showed significant difference in the four GOLD groups.For an NLR cutoff of 3.4, sensitivity for predicting unfavorable outcome of AECOPD was 88.89% and specificity was 40.07% ((AUC 0.642, p0.023) A platelets cutoff of 169, sensitivity was 40.7% (AUC 0.657, p0.024). For pco2 cutoff of 54, sensitivity was 70.37% (AUC 0.781, p 0.000). ConclusionsElevated NLR can be used as a marker similar to ESR, in the determination of increased inflammation in acutely exacerbated COPD.A prognostic role was recognized for the ABCD GOLD categories. So when we faced by a patient with AECOPD, putting the clinical evaluation, including his gold category, side by side to the simple laboratory data will give good idea about the likely prognosis.

Estimation of health risks caused by exposure to enteroviruses from agricultural application of wastewater effluents

Agricultural reuse of wastewater is a common practice worldwide, especially in arid and semiarid area due to the freshwater scarcity. Wastewater irrigation in the Middle East, one of the most water-stressed regions in the world, could be a key factor for socio-economic development, but the microbial contamination of untreated or partially treated wastewater is a serious public health concern. Potential transmission of enteric viral infections through wastewater reuse in agricultural activities represents a true health risk for exposed individuals. Accordingly, it is important to assess the health risks associated with wastewater reuse. A quantitative microbial risk assessment (QMRA) with Monte-Carlo simulation was used to estimate the annual risk of enterovirus (EV) infection and disease burden for farmers and consumers of wastewater-irrigated lettuce in Iran, a semiarid country in the Middle East region. Risk analysis was performed based on the measured concentrations of EV in effluent of two activated sludge wastewater treatment plants (WWTP). Wastewater effluent sampling was carried out over a nine-month period, and the presence of total and fecal coliforms and EV was determined. Fecal coliform bacteria were found at a high level exceeded the guideline limit for wastewater reuse in agriculture. EVs were detected in 40% of samples with the highest frequency in summer with a mean of 12 and 16 pfu/ml for WWTP-A and B, respectively. Statistical analysis showed no correlation between the concentration of fecal coliforms and EV. The estimated infection risk for EVs was 8.8 × 10−1 and 8.2 × 10−1 per person per year (pppy) for farmers of WWTP-A and -B, respectively which was about 2 log higher than the tolerable infection risk of 2 × 10−3 pppy. The estimated risk for lettuce consumers exhibited a lower level of infection and disease burden but higher than the guideline limits. The median disease burden for consumption of lettuce irrigated with activated sludge effluents was about 10−3 Disability Adjusted Life Years (DALY) pppy which exceeded the WHO guideline threshold of 10−4 DALY pppy. The results of study indicated that the activated sludge effluents require an additional reduction of EVs to achieve the acceptable level of risk for agricultural reuse of wastewater.

Measuring ventilation and modelling M. tuberculosis transmission in indoor congregate settings, rural KwaZulu-Natal.

SUMMARYSETTING: Molecular epidemiology suggests that most Mycobacterium tuberculosis transmission in high-burden settings occurs outside the home.OBJECTIVE: To estimate the risk of M. tuberculosis transmission inside public buildings in a high TB burden community in KwaZulu-Natal, South Africa.DESIGN: Carbon dioxide (CO2) sensors were placed inside eight public buildings. Measurements were used with observations of occupancy to estimate infection risk using an adaptation of the Wells-Riley equation. Ventilation modelling using CONTAM was used to examine the impact of low-cost retrofits on transmission in a health clinic.RESULTS: Measurements indicate that infection risk in the church, classroom and clinic waiting room would be high with typical ventilation, occupancy levels and visit durations. For example, we estimated that health care workers in a clinic waiting room had a 16.9–24.5% annual risk of M. tuberculosis infection. Modelling results indicate that the simple addition of two new windows allowing for cross-ventilation, at a cost of US$330, would reduce the annual risk to health care workers by 57%.CONCLUSIONS: Results indicate that public buildings in this community have a range of ventilation and occupancy characteristics that may influence transmission risks. Simple retrofits may result in dramatic reductions in M. tuberculosis transmission, and intervention studies should therefore be considered.

Cryptosporidium risk from swimming pool exposures.

Infection risk estimates from swimming in treated recreational water venues are lacking and needed to prioritize public health interventions in swimming pools. Quantitative infection risk estimates among different age groups are needed to identify vulnerable populations. High risk populations can be targeted during public health interventions, like education campaigns and pool operation improvements. This study estimated per-swim and annual Cryptosporidium infection risks in adults (>18) and children (≤18) using new experimental data collected in the U.S. on swimmer behavior. Risks were estimated using oocyst concentration data from the literature, and data collected in this study on pool water ingestion, swim duration and pool use frequency. A sensitivity analysis identified the most influential model variables on infection probability. The average estimated risk of Cryptosporidium infection was 2.6×10-4 infections/swim event. The per-swim risk estimate in the present study differed from others because behavior data (ingestion rates, swim duration, and visit frequency) were collected in different countries and varied from U.S. estimates. We found swimmer behaviors influence infection risk. This is the first study to report annual risk of Cryptosporidium infection among swimmers by age group. Using U.S. exposure data, annual risk was estimated at 2.9×10-2 infections/year for children and 2.2×10-2 infections/year for adults. Annual risk for all swimmers was estimated at 2.5×10-2 infections/year from swimming in treated recreational water venues. Due to increased ingestion and swim duration, child swimmers had the highest annual risk estimate. Cryptosporidium concentration is the most influential variable on infection probability. Results suggest the need for standardized pool water quality monitoring for Cryptosporidium, education, development of interventions to reduce ingestion, consideration of behaviors unique to swimming populations in future risk assessments and improvement of oocyst removal from pool water. Child swimmers were the most vulnerable sub-population, and should be targeted in healthy swimming education campaigns.

Potential impact of a ventilation intervention for influenza in the context of a dense indoor contact network in Hong Kong

Emerging diseases may spread rapidly through dense and large urban contact networks. We constructed a simple but novel dual-contact network model to account for both airborne contact and close contact of individuals in the densely populated city of Hong Kong. The model was then integrated with an existing epidemiological susceptible-exposed-infectious-recovered (SEIR) model, and we used a revised Wells-Riley model to estimate infection risks by the airborne route and an exponential dose-response model for risks by the contact and droplet routes. A potential outbreak of partially airborne influenza was examined, assuming different proportions of transmission through the airborne route. Our results show that building ventilation can have significant effects in airborne transmission-dominated conditions. Moreover, even when the airborne route only contributes 20% to the total infection risk, increasing the ventilation rate has a strong influence on transmission dynamics, and it also can achieve control effects similar to those of wearing masks for patients, isolation and vaccination.

Lethal exposure: An integrated approach to pathogen transmission via environmental reservoirs.

To mitigate the effects of zoonotic diseases on human and animal populations, it is critical to understand what factors alter transmission dynamics. Here we assess the risk of exposure to lethal concentrations of the anthrax bacterium, Bacillus anthracis, for grazing animals in a natural system over time through different transmission mechanisms. We follow pathogen concentrations at anthrax carcass sites and waterholes for five years and estimate infection risk as a function of grass, soil or water intake, age of carcass sites, and the exposure required for a lethal infection. Grazing, not drinking, seems the dominant transmission route, and transmission is more probable from grazing at carcass sites 1–2 years of age. Unlike most studies of virulent pathogens that are conducted under controlled conditions for extrapolation to real situations, we evaluate exposure risk under field conditions to estimate the probability of a lethal dose, showing that not all reservoirs with detectable pathogens are significant transmission pathways.

Management of bite wounds in children and adults-an analysis of over 5000 cases at a level I trauma centre.

Bite wounds are among the commonest types of trauma to which man is the subject. They account for 5 % of the total traumatic wounds evaluated in the emergency department (ED) and approximately 1 % of all the ED visits. Early estimation of infection risk, adequate antibiotic therapy and if indicated surgical treatment are the cornerstones of successful cure of bite wounds. A total of 5248 consecutive trauma patients were collected prospectively and analysed retrospectively over a period of 15 years in this study at a level I trauma centre, Department of Trauma Surgery, Medical University of Vienna, Austria. The mean age was 33.8 years (range 0-97), 2620 (49.9 %) were male and 2628 (50.1 %) were female individuals. In our study population, a total of 2530 dog bites (48.2 %), 930 cat bites (17.8 %), 357 other animal bites (6.8 %), 426 human bites (8.1 %) and 1005 human self-bites (19.2 %) have been observed. A total of 995 wounds (19.0 %) have been infected. Surgery was done in 132 wounds (2.5 %). We could show a six times higher infection rate of cat bites compared to dog bites. Human bites showed a total infection rate of 8.2 %. Observed infection rate of puncture wounds and wounds greater than 3cm was 1.5 times higher than for all other wounds in the present study. Total infection rates within 24h to antibiotic administration was 29.3 %, compared to 65.0 % < 48h and 81.1 % < 72h. Time interval also influenced the overall outcome showing a 2.6 increase in acceptable and 1.3 increase in poor outcome after 72h.

Cryptosporidium and Giardia in recreational water in Belgium.

The objective of this study was to investigate the presence of Cryptosporidium and Giardia in different recreational water bodies in Belgium and to estimate the infection risk associated with swimming and other recreational activities. Cryptosporidium oocysts and/or Giardia cysts were detected in three out of 37 swimming pools, seven out of 10 recreational lakes, two out of seven splash parks and four out of 16 water fountains. In the swimming pools no infection risk for Cryptosporidium could be calculated, since oocysts were only detected in filter backwash water. The risk of Giardia infection in the swimming pools varied from 1.13×10(-6) to 2.49×10(-6) per swim per person. In recreational lakes, the infection risk varied from 2.79×10(-5) to 5.74×10(-5) per swim per person for Cryptosporidium and from 7.04×10(-5) to 1.46×10(-4) for Giardia. For other outdoor water recreation activities the estimated infection risk was 5.71×10(-6) for Cryptosporidium and 1.47×10(-5) for Giardia. However, most positive samples in the recreational lakes belonged to species/genotypes that are either animal-specific or predominantly found in animals. No Cryptosporidium was found in splash parks and water fountains, but the presence of Giardia cysts suggests a risk for human infection. The infection risk of Giardia infection during a 3.5-minute visit to a splash park for children equalled 1.68×10(-4).

Geostatistical modelling of soil-transmitted helminth infection in Cambodia: Do socioeconomic factors improve predictions?

Soil-transmitted helminth infections are intimately connected with poverty. Yet, there is a paucity of using socioeconomic proxies in spatially explicit risk profiling. We compiled household-level socioeconomic data pertaining to sanitation, drinking-water, education and nutrition from readily available Demographic and Health Surveys, Multiple Indicator Cluster Surveys and World Health Surveys for Cambodia and aggregated the data at village level. We conducted a systematic review to identify parasitological surveys and made every effort possible to extract, georeference and upload the data in the open source Global Neglected Tropical Diseases database. Bayesian geostatistical models were employed to spatially align the village-aggregated socioeconomic predictors with the soil-transmitted helminth infection data. The risk of soil-transmitted helminth infection was predicted at a grid of 1×1km covering Cambodia. Additionally, two separate individual-level spatial analyses were carried out, for Takeo and Preah Vihear provinces, to assess and quantify the association between soil-transmitted helminth infection and socioeconomic indicators at an individual level. Overall, we obtained socioeconomic proxies from 1624 locations across the country. Surveys focussing on soil-transmitted helminth infections were extracted from 16 sources reporting data from 238 unique locations. We found that the risk of soil-transmitted helminth infection from 2000 onwards was considerably lower than in surveys conducted earlier. Population-adjusted prevalences for school-aged children from 2000 onwards were 28.7% for hookworm, 1.5% for Ascaris lumbricoides and 0.9% for Trichuris trichiura. Surprisingly, at the country-wide analyses, we did not find any significant association between soil-transmitted helminth infection and village-aggregated socioeconomic proxies. Based also on the individual-level analyses we conclude that socioeconomic proxies might not be good predictors at an aggregated large-scale analysis due to their large between- and within-village heterogeneity. Specific information of both the infection risk and potential predictors might be needed to obtain any existing association. The presented soil-transmitted helminth infection risk estimates for Cambodia can be used for guiding and evaluating control and elimination efforts.

바닥분수에서 물놀이를 하는 아동들의 Legionella균 감염 위해도 분석

최근 국내의 각종 시설들에서 경관과 여름철 물놀이를 위한 바닥분수 설치가 선호되어, 그 수가 연간 50% 이상 급증하고 있다. 본 연구는, 정량적 미생물학적 위해성 평가 방법으로, 아동이 바닥분수에서 물놀이를 하는 동안 Legionella spp.에 의한 감염 위해도가 어느 정도인지 정량 하였다. 용수 중 Legionella균의 농도를 <TEX>$10^{-1}-10^6$</TEX> CFU/L로 상정하고, 공기 중으로 에어로졸과 함께 비산하게 되는 Legionella균의 농도와 노출시간, 호흡률의 분포, 폐까지 도달하는 에어로졸의 비율을 곱하여 아동들의 노출량을 산정하고, Legionella pneumophila의 위해도를 도출하는 것으로 알려진 지수함수 모델에 따라, 감염 위해도로 변환하였다. 최고 위험군은 뛰어다니면서 물놀이를 하는 신체가 큰, 혹은 연령이 높은 아동이었으며, 이들이 <TEX>$10^4$</TEX> CFU/L 이상의 Legionella균이 존재하는 분수 용수를 1회 이상 이용 시 0.05 이상의 위해도가 발생하였다. 이 결과에 따르면, <TEX>$10^3$</TEX> CFU/L 미만의 Legionella균 농도를 공중이용시설의 모든 배관용수에 대하여 허용하는 현행 질병관리본부의 레지오넬라증 관리지침은 타당한 것으로 판정된다. 그러나, 이 기준은 건강한 성인 대상으로는 적합하나 아동의 면역력이 낮은 점을 감안하지 않았으므로, 아동에게 적합한 감염위해도 모델을 연구하여, 보다 철저한 관리 기준을 적용할 필요성이 있다. Recently interactive water fountains are gaining popularity in making public facilities in South Korea. The total number of interactive fountains is rapidly growing at the rate of >50% annually. In this study, we performed quantitative microbial risk assessment to estimate infection risks in children by Legionella spp. while playing in interactive fountains. The exposure dose for a given concentration of Legionella in water was calculated using water-aerosol partition rate of Legionella, exposure duration, inhalation rate, and deposit rate of aerosols in the lungs following inhalation. The dose was converted to infection risk by using the dose-response function developed for L. pneumophila. High weight and/or old children, i.e., 12-year children, running around in fountains were the highest risk group by showing >0.05 infection probability for fountain waters containing <TEX>${\geq}10^4$</TEX> CFU/L Legionella. The result supported the current guideline by Korea Centers for Disease Control and Prevention, which permits use of water with < <TEX>$10^3$</TEX> CFU/L Legionella cells for all purposes. However, the results still warrant further evaluation of the guideline to accommodate risks for children because the dose-response relationship in the model was developed for healthy adults. Further risk assessment studies need to be conducted by employing dose-response model for children who generally carries weaker immune system than adults.

Turbidity as a surrogate for Cryptosporidium removal by filtration in drinking-water QMRA models

A quantitative microbial risk assessment (QMRA) with Monte Carlo simulation was used to estimate risks of Cryptosporidium infection from drinking water. Four different approaches to assess Cryptosporidium oocyst removal by filtration were compared using three relationships between turbidity removal and oocyst removal proposed in the literature, and an empirical model based on oocyst log removal credits associated with filtered effluent turbidity. Using a large database of a full-scale water treatment plant in Brazil, two of the turbidity removal-based models returned 1–3 log unit removal of Cryptosporidium oocysts and median values of Cryptosporidium annual infection risk estimates of approximately 10−2pppy (per person per year). The other model based on turbidity removal and the empirical model resulted, respectively, in 2–3.5 and 0–4 log removal of Cryptosporidium oocysts and corresponding infection risk estimates around 10−2pppy, close therefore to the health-based targets of the WHO guidelines for drinking water. The results of this study indicate that the empirical model appears to be particularly suitable for QMRA studies and that similar models should be tested in other site-specific assessments of treatment performance.

Re-evaluating endoscopy-associated infection risk estimates and their implications

Re-evaluating endoscopy-associated infection risk estimates and their implications

Major Infection After Pediatric Cardiac Surgery: External Validation of Risk Estimation Model

A multivariable risk estimation model, in which the primary outcome was major infection, was recently developed and published using The Society of Thoracic Surgeons (STS) Congenital Heart Surgery Database. We have applied this risk estimation model to our congenital heart surgery program over a 16-year time interval to validate this risk estimation model and verify its specific risk factors for major infection. Using complete and verified data, we selected patients in whom major procedures had been classified using both Aristotle Basic Score and Risk Adjustment for Congenital Heart Surgery (RACHS-1) and created a multivariable model in which primary outcome was major infection (septicemia, mediastinitis, or endocarditis). We checked the STS risk estimation model for major infection. We also assessed the significance of the STS risk factors in our program. A total of 6,314 patients were analyzed. We identified 197 (3.1%) major infections (septicemia 3%, endocarditis 0.015%, mediastinitis 0.09%). Hospital mortality, ventilation time, and length of stay were greater in patients with major infections. The following preoperative risk factors identified by the STS risk estimation model were significant in multivariate analysis in our patients: young age, high complexity, medium complexity, previous operation, and preoperative ventilation (p<0.0001). Estimated infection risk ranged from 0.32% to 11.58%. The model discrimination was good (c index, 0.808). Risks of infections after most common congenital heart surgery procedures were similar in both studies (rs=0.952, p=0.0003). Our external validation study confirmed that the STS model can be used as a preoperative risk stratification tool for major infection risk at the single institutional level.

A Forecast Model for the First Occurrence of Phytophthora Blight on Chili Pepper after Overwintering

An infection risk model for Phytophthora blight on chili pepper was developed to estimate the first date of disease occurrence in the field. The model consisted of three parts including estimation of zoosporangium formation, soil water content, and amount of active inoculum in soil. Daily weather data on air temperature, relative humidity and rainfall, and the soil texture data of local areas were used to estimate infection risk level that was quantified as the accumulated amount of active inoculum during the prior three days. Based on the analysis on 190 sets of weather and disease data, it was found that the threshold infection risk of 224 could be an appropriate criterion for determining the primary infection date. The 95% confidence interval for the difference between the estimated date of primary infection and the observed date of first disease occurrence was <TEX>$8{\pm}3$</TEX> days. In the model validation tests, the observed dates of first disease occurrence were within the 95% confidence intervals of the estimated dates in the five out of six cases. The sensitivity analyses suggested that the model was more responsive to temperature and soil texture than relative humidity, rainfall, and transplanting date. The infection risk model could be implemented in practice to control Phytophthora blight in chili pepper fields.

The management of bite wounds in children—A retrospective analysis at a level I trauma centre

IntroductionAnimal bite wounds are a significant problem, which have caused several preventable child deaths in clinical practice in the past. The majority of bite wounds is caused by dogs and cats, and also humans have to be considered to lead to those extreme complicated diagnosis in the paediatric patient population. Early estimation of infection risk, adequate antibiotic therapy and, if indicated, surgical treatment, are cornerstones of successful cures of bite wounds. However, antibiotic prophylaxis and wound management are discussed controversially in the current literature. In our study, we retrospectively investigated the bite source, infection risk and treatment options of paediatric bite wounds. MethodsA total of 1592 paediatric trauma patients were analysed over a period of 19 years in this retrospective study at a level I trauma centre, Department of Trauma Surgery, Medical University of Vienna, Austria. Data for this study were obtained from our electronic patient records and follow-up visits. In our database, all paediatric patients triaged to our major urban trauma centre have been entered retrospectively. ResultsDuring the 19-year study period, 1592 paediatric trauma patients met the inclusion criteria. The mean age was 7.7years (range 0–18.9), 878 (55.2%) were males and 714 (44.8%) were females. In our study population, a total of 698 dog bites (43.8%), 694 human bites (43.6%), 138 other bites (8.7%) and 62 cat bites (3.9%) have been observed. A total of 171 wounds (10.7%) have been infected. Surgical intervention was done in 27 wounds (1.7%). ConclusionGender-related incidence in bite wounds for dog and cat could be detected. Second, our findings for originator of bite wounds reflect the findings in the published literature. Total infection rate reached 10.7%, primary antibiotic therapy was administered in 221 cases (13.9%) and secondary antibiotic therapy in 20 (1.3%) cases. Observed infection rate of punctured wounds and wounds greater than 3cm was 3 times higher than for all other wounds.Our findings need to be proven in further prospective clinical trials.

Spatially explicit Schistosoma infection risk in eastern Africa using Bayesian geostatistical modelling

Schistosomiasis remains one of the most prevalent parasitic diseases in the tropics and subtropics, but current statistics are outdated due to demographic and ecological transformations and ongoing control efforts. Reliable risk estimates are important to plan and evaluate interventions in a spatially explicit and cost-effective manner. We analysed a large ensemble of georeferenced survey data derived from an open-access neglected tropical diseases database to create smooth empirical prevalence maps for Schistosoma mansoni and Schistosoma haematobium for a total of 13 countries of eastern Africa. Bayesian geostatistical models based on climatic and other environmental data were used to account for potential spatial clustering in spatially structured exposures. Geostatistical variable selection was employed to reduce the set of covariates. Alignment factors were implemented to combine surveys on different age-groups and to acquire separate estimates for individuals aged ≤20 years and entire communities. Prevalence estimates were combined with population statistics to obtain country-specific numbers of Schistosoma infections. We estimate that 122 million individuals in eastern Africa are currently infected with either S. mansoni, or S. haematobium, or both species concurrently. Country-specific population-adjusted prevalence estimates range between 12.9% (Uganda) and 34.5% (Mozambique) for S. mansoni and between 11.9% (Djibouti) and 40.9% (Mozambique) for S. haematobium. Our models revealed that infection risk in Burundi, Eritrea, Ethiopia, Kenya, Rwanda, Somalia and Sudan might be considerably higher than previously reported, while in Mozambique and Tanzania, the risk might be lower than current estimates suggest. Our empirical, large-scale, high-resolution infection risk estimates for S. mansoni and S. haematobium in eastern Africa can guide future control interventions and provide a benchmark for subsequent monitoring and evaluation activities.

Delayed breast implant reconstruction: A 10-year prospective study

Studies of complications following reconstructive surgery with implants among women with breast cancer are needed. As the, to our knowledge, first prospective long-term study we evaluated the occurrence of complications following delayed breast reconstruction separately for one- and two-stage procedures. From the Danish Registry for Plastic Surgery of the Breast, which has prospectively registered data for women undergoing breast implantations since 1999, we identified 559 women without a history of radiation therapy undergoing 592 delayed breast reconstructions following breast cancer during the period 1999 to 2006; 239 one-stage procedures and 353 two-stage procedures. The postoperative course through November 2009 was evaluated by cumulative incidence adjusting for competing risks for the selected outcomes; hematoma, infection, seroma, implant rupture, severe capsular contracture (modified Baker III and IV), extrusion of the implant, asymmetry/displacement of the implant, any complication, and reoperation. These analyses were performed both overall and separately according to type of procedure (one- or two-stage). The overall 10-year risk estimates were 68.1% for any complication, 7.7% for severe capsular contracture, 32.3% for displacement/asymmetry of the implant and 38.6% for reoperation. When comparing one- and two-stage procedures, we observed significantly higher risk estimates for infection, seroma and extrusion of the implant following two-stage procedures, whereas the risk of reoperation was significantly higher following the one-stage procedure. For both procedures, the majority of reoperations were due to asymmetry or displacement of the implant. In conclusion, non-radiated one- and two-stage delayed breast implant reconstructions are associated with substantial risks of complications and reoperation which should be taken into consideration in the planning of breast reconstruction.