Duration Of Outbreak Research Articles

The burden of gastroenteritis outbreaks in long-term care settings in Philadelphia, 2009-2018.

Gastroenteritis causes significant morbidity and mortality in long-term care facility (LTCF) residents, a growing population within the United States. We set out to better understand gastroenteritis outbreaks in LTCF by identifying outbreak and facility characteristics associated with outbreak incidence as well as outbreak duration and size. We conducted a retrospective cross-sectional study on LTCFs in Philadelphia County from 2009 to 2018. Outbreak characteristics and interventions were extracted from Philadelphia Department of Public Health (PDPH) database and quality data on all LTCFs was extracted from Centers for Medicare and Medicaid Services Nursing Home Compare database. We identified 121 gastroenteritis outbreaks in 49 facilities. Numbers of affected patients ranged from 2 to 211 patients (median patient illness rate, 17%). Staff were reported ill in 94 outbreaks (median staff illness rate, 5%). Outbreak facilities were associated with higher occupancy rates (91% vs 88%; P = .033) and total bed numbers (176 vs 122; P = .071) compared to nonoutbreak facilities. Higher rates of staff illness were associated with prolonged outbreaks (13% vs 4%; P < .001) and higher patient illness rates (9% vs 4%; P = .012). Prolonged outbreaks were associated with lower frequency of cohorting for outbreak management (13% vs 41%; P = .046). This study is the largest published analysis of gastroenteritis outbreaks in LTCFs. Facility characteristics and staff disease activity were associated with more severe outbreaks. Heightened surveillance for gastrointestinal symptoms among staff and increased use of cohorting might reduce the risk of prolonged gastroenteritis outbreaks in LTCF.

Systematic review of healthcare-associated Burkholderia cepacia complex outbreaks: presentation, causes and outbreak control

SummaryBackgroundOver the past decades, the Burkholderia cepacia complex (BCC) has been linked to multiple healthcare-associated outbreaks. No systematic analysis of these outbreaks has been carried out to date. The aim of this study was to conduct a systematic review of reports on nosocomial BCC outbreaks.MethodsPublished studies from 1971 until 9/12/2019 presenting nosocomial BCC outbreaks were identified using Embase, Pubmed and abstracts from professional meetings.ResultsWe identified a total of 111 outbreak reports. Thirty-two percent of the affected institutions were academic hospitals and 43.8% community hospitals. The average outbreak duration was 198.6 ± 604.4 days. A total of 240 deaths (10% of the 2390 case patients) were reported but only 28 (1.2% of the 2390 case patients and 11.7% of the 240 deaths) were directly attributable to BCC. The source could be identified in 73.9% of the outbreaks; 53.2% were caused by contaminated medical solutions and medications, 12% were due to a contaminated disinfectant. In 28.2% of the outbreaks intrinsic product contamination was reported. Multidrug resistance was noted in 26.1% of the BCC strains. PFGE was the most frequently used typing method (43.2%) in the context of outbreak work-up.ConclusionMedical products are the most frequent source of BCC outbreaks, representing over half of the identified sources, with 12% of the outbreaks caused by disinfectant products. Intrinsic product contamination was detected frequently, suggesting a need for stricter regulation. While BCC-related mortality was low, our systematic review revealed significant heterogeneity in both investigations and reporting of BCC outbreaks.

The psychological impact on an orthopaedic outpatient setting in the early phase of the COVID-19 pandemic: a cross-sectional study

BackgroundWorld Health Organization declared coronavirus disease-19 (COVID-19) a global pandemic on 11 March 2020, after the coronavirus claimed 4628 lives worldwide. Mental health challenges such as making impossible decisions and working under extreme pressures are expected to be faced by frontline healthcare workers who are directly involved in the care of COVID-19 patients. However, we question if significant stress levels might also be observed in a subspecialty musculoskeletal outpatient department, where staff are not first-line care providers of COVID-19 patients. We hypothesize that these healthcare workers also face significant psychological strain, and we aim to objectively determine the prevalence using a validated caregiver strain index.MethodsA cross-sectional study was conducted in outpatient musculoskeletal clinics in a tertiary hospital in Singapore. We collected basic demographic data and used a 13-question tool adapted from the validated Caregiver Strain Index (CSI) to measure psychological strain in these healthcare workers. Participants were divided into 2 groups depending on the level of strain experienced.ResultsA total of 62 healthcare workers volunteered for this study. There were 32 participants (51.6%) who had 7 or more positive responses (group 1) and the remaining 30 participants (48.4%) were allocated to group 2. There were no significant differences between the two groups in terms of demographic data. “Work adjustments” (74.2%), “changes in personal plans” (72.6%), and finding it “confining” (72.6%) garnered the most positive responses in the questionnaire. On the other hand, “financial concerns” garnered the least positive responses (21.0%).ConclusionThe protracted duration of the COVID-19 outbreak and its resultant prolonged adjustments can have unintended consequences of wearing down healthcare resources otherwise allocated to chronic and elective conditions. Countries should ensure that measures are put in place to safeguard the mental well-being of our healthcare workers to avoid needing another reactive strategy in this battle against COVID-19.

Comparative infection modeling and control of COVID-19 transmission patterns in China, South Korea, Italy and Iran

The COVID-19 has become a pandemic. The timing and nature of the COVID-19 pandemic response and control varied among the regions and from one country to the other, and their role in affecting the spread of the disease has been debated. The focus of this work is on the early phase of the disease when control measures can be most effective. We proposed a modified susceptible-exposed-infected-removed model (SEIR) model based on temporal moving windows to quantify COVID-19 transmission patterns and compare the temporal progress of disease spread in six representative regions worldwide: three Chinese regions (Zhejiang, Guangdong and Xinjiang) vs. three countries (South Korea, Italy and Iran). It was found that in the early phase of COVID-19 spread the disease follows a certain empirical law that is common in all regions considered. Simulations of the imposition of strong social distancing measures were used to evaluate the impact that these measures might have had on the duration and severity of COVID-19 outbreaks in the three countries. Measure-dependent transmission rates followed a modified normal distribution (empirical law) in the three Chinese regions. These rates responded quickly to the launch of the 1st-level Response to Major Public Health Emergency in each region, peaking after 1–2 days, reaching their inflection points after 10–19 days, and dropping to zero after 11–18 days since the 1st-level response was launched. By March 29th, the mortality rates were 0.08% (Zhejiang), 0.54% (Guangdong) and 3.95% (Xinjiang). Subsequent modeling simulations were based on the working assumption that similar infection transmission control measures were taken in South Korea as in Zhejiang on February 25th, in Italy as in Guangdong on February 25th, and in Iran as in Xinjiang on March 8th. The results showed that by June 15th the accumulated infection cases could have been reduced by 32.49% (South Korea), 98.16% (Italy) and 85.73% (Iran). The surface air temperature showed stronger association with transmission rate of COVID-19 than surface relative humidity. On the basis of these findings, disease control measures were shown to be particularly effective in flattening and shrinking the COVID-10 case curve, which could effectively reduce the severity of the disease and mitigate medical burden. The proposed empirical law and the SEIR-temporal moving window model can also be used to study infectious disease outbreaks worldwide.

A mechanistic, stigmergy model of territory formation in solitary animals: Territorial behavior can dampen disease prevalencebut increase persistence.

Although movement ecology has leveraged models of home range formation to explore the effects of spatial heterogeneity and social cues on movement behavior, disease ecology has yet to integrate these potential drivers and mechanisms of contact behavior into a generalizable disease modeling framework. Here we ask how dynamic territory formation and maintenance might contribute to disease dynamics in a territorial, solitary predator for an indirectly transmitted pathogen. We developed a mechanistic individual-based model where stigmergy-the deposition of signals into the environment (e.g., scent marking, scraping)-dictates local movement choices and long-term territory formation, but also the risk of pathogen transmission. Based on a variable importance analysis, the length of the infectious period was the single most important variable in predicting outbreak success, maximum prevalence, and outbreak duration. Host density and rate of pathogen decay were also key predictors. We found that territoriality best reduced maximum prevalence in conditions where we would otherwise expect outbreaks to be most successful: slower recovery rates (i.e., longer infectious periods) and higher conspecific densities. However, for slower pathogen decay rates, stigmergy-driven movement increased outbreak durations relative to random movement simulations. Our findings therefore support a limited version of the "territoriality benefits" hypothesis-where reduced home range overlap leads to reduced opportunities for pathogen transmission, but with the caveat that reduction in outbreak severity may increase the likelihood of pathogen persistence. For longer infectious periods and higher host densities, key trade-offs emerged between the strength of pathogen load, the strength of the stigmergy cue, and the rate at which those two quantities decayed; this finding raises interesting questions about the evolutionary nature of these competing processes and the role of possible feedbacks between parasitism and territoriality. This work also highlights the importance of considering social cues as part of the movement landscape in order to better understand the consequences of individual behaviors on population level outcomes.

An updated analysis of turning point, duration and attack rate of COVID-19 outbreaks in major Western countries with data of daily new cases.

As coronavirus spreads around the world, the study of its effects is of great practical significance. We collated data on daily new cases of the COVID-19 outbreaks in the six Western countries of the Group of Seven and the dates of governments’ interventions. We studied the periods before and after the dates of major governments’ interventions integrally based on a segmented Poisson model. The relevant results are published in the paper of “Predicting turning point, duration and attack rate of COVID - 19 outbreaks in major Western countries” [1]. Our method can be used to update prediction daily as COVID-19 outbreaks evolve. In this article, we illustrate an updated analysis with our method to facilitate reproducibility. Both datasets used and updated are provided.

Predicting turning point, duration and attack rate of COVID-19 outbreaks in major Western countries.

In this paper, we employed a segmented Poisson model to analyze the available daily new cases data of the COVID-19 outbreaks in the six Western countries of the Group of Seven, namely, Canada, France, Germany, Italy, UK and USA. We incorporated the governments' interventions (stay-at-home advises/orders, lockdowns, quarantines and social distancing) against COVID-19 into consideration. Our analysis allowed us to make a statistical prediction on the turning point (the time that the daily new cases peak), the duration (the period that the outbreak lasts) and the attack rate (the percentage of the total population that will be infected over the course of the outbreak) for these countries.

Features of impact of hyperferritinemia in combination with hyperuricemia on the course of gout.

The purpose of the study is to find out the frequency of development of hyperfer­ritinemia in combination with hyperuricemia in patients with gout, to assess their pathogenetic significance and to outline their role in the development of joint syndrome, to identify informative prognostic criteria. 72 patients with gout were examined. The 1st (main) group included 37 patients with gout with hyperuricemia combined with hyper­ferritinemia, whose mean age (SD) was 55.9 (10.7) years. Group 2 (comparison group) included 35 patients with gout and hyperuricemia and normal levels of ferritin (mean age - 52.8 (4.8) years). Group 3 (control) group included 20 practically healthy individuals (mean age 52.0 (2.9) years). The average level of blood uric acid was significantly dif­ferent (p=0.0254) in the main group and the comparison group and amounted to 464.5 (122.5) μmol/L and 403.8 (403.8; 403.8), respectively. The value of ferritin in the main group was significantly higher 410.2 (356.2; 415.2), p&lt;0.01) ng/mL, than in the comparison group (132.1 (20.5) ng/mL, as well as the values of the urine uric acid and C-reactive protein values (hs-CRP) (p=0.0001) 8.2 (6.0; 8.2) and 5.8 (6.1) mg/L, respectively. A direct reliable cor­relation was established (r=0.30; p&lt;0.05) between the level of blood uric acid and ferritin, the duration of gout (r=0.41; p&lt;0.05), the total number of affected joints (r=0.35; p&lt;0.03), the severity of gout (r=0.36; p&lt;0.05), as well as between the level of ferritin and the number of exacerbations of gout (r=0.44; p&lt;0.05). Hyperferritinemia in com­bination with hyperuricemia is found in 51.0% of patients with gout, significantly worsening the course of the inflammatory process Patients with gout and high levels of ferritin, unlike patients with normal levels of ferritin, have the following clinical anamnestic signs: greater number of exacerbations of gout per year, duration of gout and last outbreak of gout, exacerbation of arthritis, total number of affected joints, pain intensity during exacerbation by scale VAS. In patients with gout, the severity of the course and the form of gouty arthritis, which are determined according to imaging methods (erosion, peripheral and bone tophus, the sign of "double contour", the degree of narrowing of the joint gaps and the severity of subchondral sclerosis), have prognostic significance. The association of ferritin with blood uric acid in gout does not depend on the level of hs-CRP.

SARS-CoV-2 Infection in Health Care Workers: A Retrospective Analysis and Model Simulations of a Nosocomial Outbreak

Background: There had been a preliminary occurrence of human-to-human transmissions between healthcare workers (HCWs), but risk factors in the susceptibility for COVID-19, and infection patterns among HCWs have largely remained unknown. Methods: Retrospective data collection on demographics, lifestyles, contact status with infected subjects for 118 HCWs (include 12 COVID-19 HCWs) from a single-center. Sleep quality and working pressure were evaluated by Pittsburgh Sleep Quality Index (PSQI) and The Nurse Stress Index (NSI), respectively. Follow-up duration was from Dec 25, 2019, to Feb 15, 2020. Risk factors and transmission models of COVID-19 among HCWs were analyzed and constructed. Findings: A high proportion of COVID-19 HCWs had engaged in night shift-work (75.0% vs. 40.6%) and felt they were working under pressure (66.7% vs. 32.1%) than uninfected HCWs. COVID-19 HCWs had higher total scores of PSQI and NSI than uninfected HCWs. Furthermore, these scores were both positively associated with COVID-19 risk. An individual-based model (IBM) estimated the outbreak duration among HCWs in a non-typical COVID-19 ward at 62-80 days and the basic reproduction number =1.27 [1.06, 1.61]. By reducing the average contact rate per HCW by a 1.35 factor and susceptibility by a 1.40 factor, we can avoid an outbreak of the basic case among HCWs. Interpretation: Poor sleep quality and high working pressure were positively associated with high risks of COVID-19. A novel IBM of COVID-19 transmission is suitable for simulating different outbreak patterns in a hospital setting. Funding Statement: This work was supported by the Fundamental Research Funds for the Central Universities (grant 2020kfyXGYJ010 to Dr. X. Jiang). Declaration of Interests: None. Ethics Approval Statement: This study was approved by the institutional ethics board of Union Hospital, Tongji Medical College, Huazhong University of Science and Technology (No. 20200029).

Modelling Spatial and Temporal Patterns of African Swine Fever in an Isolated Wild Boar Population to Support Decision-Making.

African swine fever (ASF) is a highly contagious disease affecting all suids including wild boar. As the disease can damage commercial pig production and its circulation can threaten international trade, understanding the risks produced by free-living wild boar (as a wildlife reservoir) is important to ensure proportionate policies to exclude the disease, as well as an effective contingency response. The recent spread of the virus into Western Europe has produced concerns in many stakeholders including pig producers and national governments. Unlike in mainland Europe, where wild boar are widespread, in Britain, free-living populations have only recently re-established, and whilst these are still relatively small and isolated, they may provide a sufficient reservoir capable of sustaining disease and may thus present a continual source of infection risk to domestic pigs. This study focuses on one component of the risk produced by wild boar, specifically the distribution and persistence of virus in a landscape produced by the natural circulation of disease within wild boar. We used a spatial individual-based model run across a representation of a real landscape to explore the epidemiological consequences of an introduction of ASF into the Forest of Dean, currently hosting the largest population of wild boar in England. We explore various scenarios including variations in the prophylactic management of boar, as well as variations in reactive management (contingency response) following the detection of disease to evaluate their value in reducing this specific risk (presence of ASF virus of wild boar origin in the landscape). The abundance and distribution of wild boar is predicted to increase across our study extent over the next 20 years. Outbreaks of ASF are not predicted to be self-sustaining, with the median time to disease “burn-out” (no new infections) being 14 weeks. Carcass removal, as a tool in a package of reactive management, was of limited value in reducing the duration of outbreaks in this study. We suggest that useful predictions of some of the risks produced by ASF might be possible using only the distribution of the boar, rather than more difficult abundance or density measures.

Typhoid Outbreaks, 1989-2018: Implications for Prevention and Control.

.Typhoid fever remains an important public health problem in low- and middle-income countries, with large outbreaks reported from Africa and Asia. Although the WHO recommends typhoid vaccination for control of confirmed outbreaks, there are limited data on the epidemiologic characteristics of outbreaks to inform vaccine use in outbreak settings. We conducted a literature review for typhoid outbreaks published since 1990. We found 47 publications describing 45,215 cases in outbreaks occurring in 25 countries from 1989 through 2018. Outbreak characteristics varied considerably by WHO region, with median outbreak size ranging from 12 to 1,101 cases, median duration from 23 to 140 days, and median case fatality ratio from 0% to 1%. The largest number of outbreaks occurred in WHO Southeast Asia, 13 (28%), and African regions, 12 (26%). Among 43 outbreaks reporting a mode of disease transmission, 24 (56%) were waterborne, 17 (40%) were foodborne, and two (5%) were by direct contact transmission. Among the 34 outbreaks with antimicrobial resistance data, 11 (32%) reported Typhi non-susceptible to ciprofloxacin, 16 (47%) reported multidrug-resistant (MDR) strains, and one reported extensively drug-resistant strains. Our review showed a longer median duration of outbreaks caused by MDR strains (148 days versus 34 days for susceptible strains), although this difference was not statistically significant. Control strategies focused on water, sanitation, and food safety, with vaccine use described in only six (13%) outbreaks. As typhoid conjugate vaccines become more widely used, their potential role and impact in outbreak control warrant further evaluation.

Direct transmission via households informs models of disease and intervention dynamics in cholera

While several basic properties of cholera outbreaks are common to most settings—the pathophysiology of the disease, the waterborne nature of transmission, and others—recent findings suggest that transmission within households may play a larger role in cholera outbreaks than previously appreciated. Important features of cholera outbreaks have long been effectively modeled with mathematical and computational approaches, but little is known about how variation in direct transmission via households may influence epidemic dynamics. In this study, we construct a mathematical model of cholera that incorporates transmission within and between households. We observe that variation in the magnitude of household transmission changes multiple features of disease dynamics, including the severity and duration of outbreaks. Strikingly, we observe that household transmission influences the effectiveness of possible public health interventions (e.g. water treatment, antibiotics, vaccines). We find that vaccine interventions are more effective than water treatment or antibiotic administration when direct household transmission is present. Summarizing, we position these results within the landscape of existing models of cholera, and speculate on its implications for epidemiology and public health.

Factors associated with adverse outcomes during influenza outbreaks in aged care facilities

ObjectiveTo explore factors associated with adverse outcomes during influenza outbreaks in residential aged care facilities. MethodsA retrospective cohort study of all outbreaks reported to three Sydney metropolitan Public Health Units during 2017. ResultsA total of 123 outbreaks affected 1,787 residents and 543 staff. Early notification to a Public Health Unit was associated with shorter outbreak duration (p<0.001; B=0.674). Resident attack rates and resident mortality rates were lower in outbreaks notified early, on univariate analysis (p=0.034 and p=0.048 respectively) but not on an adjusted model. Staff attack rates were significantly associated with resident attack rates (p=0.001; B=0.736). Data on staff vaccination rates was incomplete and reported coverage rates were low (median 39%). Resident vaccination coverage ≥95% was associated with shorter outbreak duration in univariate testing but not on an adjusted model. ConclusionsEarly public health notification is associated with improved outbreak parameters; sick staff may pose a risk to residents, yet vaccination rates are low. Resident vaccination may also be valuable. Implications for public healthMeasures that facilitate early PHU involvement in influenza outbreaks should be implemented, such as compulsory reporting requirements and processes that permit easier notification through technology. Actions that enhance staff and resident vaccination coverage should also be undertaken.

Mountain pine beetle outbreak duration and pine mortality depend on direct control effort

The efficacy of direct control methods in bark beetle outbreaks is a disputed topic. While some studies report that control reduces tree mortality, others see little effect. Existing models, linking control rate to beetle population dynamics and tree infestations, give insights, but there is a need to take into account the environment spatial variability and its impact on beetle life cycle. Here, we use natural variability found in a carefully monitored and controlled infestation to simulate outbreak dynamics under different control effort and to explore the impact of control on outbreaks suppression and tree mortality. Our semi-empirical predictive model of the number of infested trees as a function of ecological and environmental variables is coupled to a simulation model for infestation dynamics. We show that even a little control can have a major impact on the number of infested trees after several years of sustained effort. However, a moderate control of 60% is required to reduce the beetle population on the long term. Furthermore, a control rate of 69%–83% is needed to achieve outbreak suppression in under 13 years depending on the abundance of incoming flights from outside sources.

Temporal variation of dust aerosol pollution in northern China

By employing the sandstorm dataset from meteorological station observations, the temporal and spatial variations in dust outbreak duration in the source regions and visibility variations over the downwind regions of northern China were analyzed over the past four decades. The statistics and wind field analyses reveal that after the early 2000s, the duration of dust outbreaks over the potential source areas of northern China had decreased by 63% compared with that in the 1970s, which suggests that the dust aerosol emission intensities in the region were significantly reduced. However, although the potential dust aerosol emission intensities were significantly reduced, the visibility during dust aerosol emission periods increased by only 25%. The emerging potential source areas in the eastern regions, variations in the wind field, increases in up-air winds, and decreases in surface winds all contribute to the observed continued high dust aerosol pollution in northern China since the early 2000s.

Widespread outbreaks of the emerging mandarinfish ranavirus (MRV) both in natural and ISKNV-FKC vaccinated mandarinfish Siniperca chuatsi in Guangdong, South China, 2017

Widespread outbreaks of mandarinfish (Siniperca chuatsi) ranavirus (MRV) have emerged in many mandarinfish farms in Guangdong, the most important region of the mandarinfish industry in China. Unlike the early typical clinical signs of abnormally swollen abdomens due to extremely severe ascites, diseased fish from the reemerging natural outbreaks of MRVs had little ascites but showed lethargy, anorexia and a typical sleepy syndrome. The disease duration of the natural outbreak of MRV could last for 1 to 5 months. Additionally, the majority of the surviving fish showed persistent anorexia and body emaciation and deformity, which is also very different from the symptoms of mandarinfish infectious spleen and kidney necrosis virus (ISKNV)—the notorious and well-known iridoviral agent in the mandarinfish industry. Mandarinfish vaccinated with the ISKNV-inactivated vaccine showed no protective effect against the natural outbreak of MRV, whereas the ISKNV vaccine seamed to induce a stronger outbreak of the MRV disease in MRV carrier fish. By real-time quantitative PCR, the liver, spleen, kidney as well as intestine are shown to be the major viral reservoirs, both under artificial infection and natural outbreak. Additionally, histopathology, immuno-histochemistry, immunofluorescence assay and transmission electron microscopy also confirmed the pathogenicity of MRV to mandarinfish. Collectively, the emerging MRV disease remained a severe and actual threat to the mandarinfish industry. As two different genera members in the family Iridoviridae, the ISKNV vaccine provided no cross-protection against MRV. A combination vaccine, containing both ISKNV and MRV, is urgently needed.

Estimating effectiveness of case-area targeted response interventions against cholera in Haiti.

Case-area targeted interventions (CATIs) against cholera are conducted by rapid response teams, and may include various activities like water, sanitation, hygiene measures. However, their real-world effectiveness has never been established. We conducted a retrospective observational study in 2015-2017 in the Centre department of Haiti. Using cholera cases, stool cultures and CATI records, we identified 238 outbreaks that were responded to. After adjusting for potential confounders, we found that a prompt response could reduce the number of accumulated cases by 76% (95% confidence interval, 59 to 86) and the outbreak duration by 61% (41 to 75) when compared to a delayed response. An intense response could reduce the number of accumulated cases by 59% (11 to 81) and the outbreak duration by 73% (49 to 86) when compared to a weaker response. These results suggest that prompt and repeated CATIs were significantly effective at mitigating and shortening cholera outbreaks in Haiti.

Ebola virus disease outbreak in Korea: use of a mathematical model and stochastic simulation to estimate risk

OBJECTIVESAccording to the World Health Organization, there have been frequent reports of Ebola virus disease (EVD) since the 2014 EVD pandemic in West Africa. We aim to estimate the outbreak scale when an EVD infected person arrives in Korea.METHODSWestern Africa EVD epidemic mathematical model SEIJR or SEIJQR was modified to create a Korean EVD outbreak model. The expected number of EVD patients and outbreak duration were calculated by stochastic simulation under the scenarios of Best case, Diagnosis delay, and Case missing.RESULTSThe 2,000 trials of stochastic simulation for each scenario demonstrated the following results: The possible median number of patients is 2 and the estimated maximum number is 11 when the government intervention is proceeded immediately right after the first EVD case is confirmed. With a 6-day delay in diagnosis of the first case, the median number of patients becomes 7, and the maximum, 20. If the first case is missed and the government intervention is not activated until 2 cases of secondary infection occur, the median number of patients is estimated at 15, and the maximum, at 35.CONCLUSIONSTimely and rigorous diagnosis is important to reduce the spreading scale of infection when a new communicable disease is inflowed into Korea. Moreover, it is imperative to strengthen the local surveillance system and diagnostic protocols to avoid missing cases of secondary infection.

Fluorescent biomarkers demonstrate prospects for spreadable vaccines to control disease transmission in wild bats.

Vaccines that autonomously transfer among individuals have been proposed as a strategy to control infectious diseases within inaccessible wildlife populations. However, rates of vaccine spread and epidemiological efficacy in real world systems remain elusive. Here, we investigated whether topical vaccines that transfer among individuals through social contacts can control vampire bat rabies, a medically and economically important zoonosis in Latin America. Field experiments in 3 Peruvian bat colonies which used fluorescent biomarkers as a proxy for the bat-to-bat transfer and ingestion of an oral vaccine revealed that vaccine transfer would increase population-level immunity up to 2.6 times beyond the same effort using conventional, non-spreadable vaccines. Mathematical models demonstrated that observed levels of vaccine transfer would reduce the probability, size, and duration of rabies outbreaks, even at low, but realistically achievable levels of vaccine application. Models further predicted that existing vaccines provide substantial advantages over culling bats, the policy currently implemented in North, Central, and South America. Linking field studies with biomarkers to mathematical models can inform how spreadable vaccines may combat pathogens of health and conservation concern prior to costly investments in vaccine design and testing.

Tuberculosis outbreaks among students in mainland China: a systematic review and meta-analysis

BackgroundIn recent years, tuberculosis outbreaks in schools have occurred more frequently in China than in other parts of the world, and have posed a public health threat to students and their families. This systematic review aimed to understand the epidemiological characteristics of tuberculosis (TB) outbreaks and analyze the factors associated with TB outbreaks in schools in China.MethodsWe conducted this systematic review following the standard procedures of the Cochrane Collaboration and the Preferred Reporting Items for Systematic Review and Meta-Analysis statement. The meta-analysis was performed with STATA using a random effects model.ResultsWe included 107 studies involving 1795 student patients with TB in mainland China. The results of the systematic analysis indicated that TB outbreaks were more frequently reported in senior middle schools and in Eastern China. The outbreaks mainly occurred during the winter and spring, and the median outbreak duration was 4 months. The meta-analysis showed that the total attack rate and the class attack rate of tuberculosis outbreaks among students were 4.60% (95% CI 3.80 to 5.70%) and 22.70% (95% CI 19.20 to 27.00%), respectively. Subgroup analysis showed that outbreaks that occurred at universities or colleges had a relatively higher attack rate than those occurred in senior middle schools. The prevalence of latent tuberculosis infection (LTBI) among close contacts was 23.70% (95% CI 19.50 to 28.90%). The median case-finding interval was 2 months, and 47.40% of the index cases had a case-finding delay.ConclusionThe results of our review indicated that school TB outbreaks were reported most frequently in senior middle schools in China. The attack rates of outbreaks at universities or colleges were higher than those in senior middle schools. The TB outbreaks in schools usually occurred over prolonged periods. The case-finding delay in the index cases must be reduced to prevent transmission in classes and schools. Effective surveillance and screening of presumptive TB cases in schools should be strengthened to reduce outbreaks in schools.