The role of internists during epidemics, outbreaks, and bioterrorist attacks.
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ABSTRACT:
SUBMITTER: Lee BY
PROVIDER: S-EPMC1824729 | biostudies-other | 2007 Jan
REPOSITORIES: biostudies-other
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Project description:Epidemic spreading has been studied for a long time and most of them are focused on the growing aspect of a single epidemic outbreak. Recently, we extended the study to the case of recurrent epidemics (Sci. Rep. 5, 16010 (2015)) but limited only to a single network. We here report from the real data of coupled regions or cities that the recurrent epidemics in two coupled networks are closely related to each other and can show either synchronized outbreak pattern where outbreaks occur simultaneously in both networks or mixed outbreak pattern where outbreaks occur in one network but do not in another one. To reveal the underlying mechanism, we present a two-layered network model of coupled recurrent epidemics to reproduce the synchronized and mixed outbreak patterns. We show that the synchronized outbreak pattern is preferred to be triggered in two coupled networks with the same average degree while the mixed outbreak pattern is likely to show for the case with different average degrees. Further, we show that the coupling between the two layers tends to suppress the mixed outbreak pattern but enhance the synchronized outbreak pattern. A theoretical analysis based on microscopic Markov-chain approach is presented to explain the numerical results. This finding opens a new window for studying the recurrent epidemics in multi-layered networks.
| S-EPMC5445088 | biostudies-literature
Project description:The study of recurrent epidemic outbreaks has been attracting great attention for decades, but its underlying mechanism is still under debate. Based on a large number of real data from different cities, we find that besides the seasonal periodic outbreaks of influenza, there are also non-periodic outbreaks, i.e. non-seasonal or non-annual behaviors. To understand how the non-periodicity shows up, we present a network model of SIRS epidemic with both time-dependent infection rate and a small possibility of persistent epidemic seeds, representing the influences from the larger annual variation of environment and the infection generated spontaneously in nature, respectively. Our numerical simulations reveal that the model can reproduce the non-periodic outbreaks of recurrent epidemics with the main features of real influenza data. Further, we find that the recurrent outbreaks of epidemic depend not only on the infection rate but also on the density of susceptible agents, indicating that they are both the necessary conditions for the recurrent epidemic patterns with non-periodicity. A theoretical analysis based on Markov dynamics is presented to explain the numerical results. This finding may be of significance to the control of recurrent epidemics.
| S-EPMC4629194 | biostudies-literature
Project description:BackgroundThe COVID-19 pandemic could worsen adolescent sexual and reproductive health (ASRH). We sought evidence on the indirect impacts of previous infectious disease epidemics and the current COVID-19 pandemic on the uptake of ASRH in sub-Saharan Africa (SSA) to design relevant digital solutions.MethodsWe undertook a literature scoping review to synthesize evidence on the indirect impacts of COVID-19 on ASRH in SSA per the Arksey and O'Malley framework and PRISMA reporting guidelines. We conducted the search on PubMed, Embase, Google Scholar, and ResearchGate in June and November 2020. We included all peer-reviewed, English-language primary studies on the indirect impacts of infectious disease epidemics on the uptake of sexual and reproductive health (SRH) in SSA.ResultsWe included 21 of 42 identified studies. Sixteen studies (76.2%) quantitatively assessed utilization and access to SRH during epidemics. Five studies (2 [9.6%] qualitative and 3 [14.3%] mixed methods) explored factors affecting SRH services. All studies focused on adult populations, most often on labor and delivery (n = 13 [61.9%]) and family planning (n = 8 [38.1%]) outcomes. Although we sought out to assess all outbreaks, epidemics, and pandemics, the only relevant studies took place during the West African Ebola pandemic (n = 17 [80.9%]) and COVID-19 pandemic (n = 4 [19.0%]). One study (4.8%) highlighted adolescent-specific outcomes and condom use. Most studies found declined access to and utilization of facility delivery, antenatal care, family planning, and HIV care. One study noted an increase in adolescent pregnancies. However, other studies noted similar, or even increasing trends in access to and utilization of other SRH services (family planning visits; HIV diagnosis; ART initiation) during epidemics. Barriers to SRH uptake included factors such as a reduced ability to pay for care due to lost income, travel restrictions, and fear of infection. Supply-side barriers included lack of open facilities, workers, commodities, and services. Community-based peer delivery systems, telemedicine, and transport services improved SRH uptake.ConclusionAccess to SRH services during epidemics among adolescents and young people in SSA is understudied. We found that no studies focused on SRH outcomes of abortion, emergency contraception, sexually transmitted infections, or cervical cancer. To improve access to and utilization of SRH during pandemics, we recommend the following; in terms of research, key standardized SRH indicators should be included in routine data collection, routine data should be disaggregated by age, gender, and geography to understand gaps in ASRH service delivery, and additional rigorous epidemiological and social-behavioral studies should be conducted. On implementation, community-based peer delivery systems and telemedicine, internet-based, and other technological solutions may better reach adolescent and young people in SSA.
| S-EPMC9361234 | biostudies-literature
Project description:Vaccination rates are on the decline as parents avoid doctor's visits with their children. In addition, the antivaccination movement has led to a significant portion of the population remaining unvaccinated or undervaccinated. Outbreaks in the United States within the past year have highlighted the need for better education and communication regarding the efficacy and safety of vaccinations as well as important steps to reduce disease transmission. Patients may be fearful and have questions about how these outbreaks will affect themselves and their families, especially those in immunocompromised states and pregnant women. Pharmacists are poised to provide this education and start a dialogue with patients and other health care professionals with regard to disease outbreaks. Additionally, in times of outbreak, pharmacists encounter obscure questions from both healthy and at-risk populations that fear contraction of a particular disease. The purpose of this commentary is to describe previous outbreaks and to explore the pharmacists' role in disease prevention.
| S-EPMC7337136 | biostudies-literature
Project description:In 1977, the world witnessed both the eradication of smallpox and the beginning of the modern age of genomics. Over the following half-century, 7 epidemic viruses of international concern galvanized virologists across the globe and led to increasingly extensive virus genome sequencing. These sequencing efforts exerted over periods of rapid adaptation of viruses to new hosts, in particular, humans provide insight into the molecular mechanisms underpinning virus evolution. Investment in virus genome sequencing was dramatically increased by the unprecedented support for phylogenomic analyses during the COVID-19 pandemic. In this review, we attempt to piece together comprehensive molecular histories of the adaptation of variola virus, HIV-1 M, SARS, H1N1-SIV, MERS, Ebola, Zika, and SARS-CoV-2 to the human host. Disruption of genes involved in virus-host interaction in animal hosts, recombination including genome segment reassortment, and adaptive mutations leading to amino acid replacements in virus proteins involved in host receptor binding and membrane fusion are identified as the key factors in the evolution of epidemic viruses.
| S-EPMC9346483 | biostudies-literature
Project description:There is limited information on the roles of different age groups in propagating pertussis outbreaks, and the temporal changes in those roles since the introduction of acellular pertussis vaccines. The relative roles of different age groups in propagating the 2010 and the 2014 pertussis epidemics in California were evaluated using the relative risk (RR) statistic that measures the change in the group's proportion among all detected cases before vs. after the epidemic peak. For the 2010-11 epidemic, evidence for a predominant transmission age group was weak, with the largest RR estimates being 1.26 (95% CI 1.08-1.46) (aged 11-13 years); 1.19 (1.01-1.4) (aged 9-10 years); 1.17 (0.86-1.59) (aged 14-15 years); 1.12 (0.86-1.46) (aged 16-19 years) and 1.1 (0.89-1.36) (aged 7-8 years). The 2014 epidemic showed a strong signal of the role of older adolescents, with the highest RR estimate being in those aged 14-15 years (RR = 1.83, 1.61-2.07), followed by adolescents aged 16-19 years (RR = 1.41, 1.24-1.61) and 11-13 years (RR = 1.26, 1.12-1.41), with lower RR estimates in other age groups. As the time following introduction of acellular pertussis vaccines in California progressed, older adolescents played an increasing role in transmission during the major pertussis outbreaks. Booster pertussis vaccination for older adolescents with vaccines effective against pertussis transmission should be considered with the aim of mitigating future pertussis epidemics in the community.
| S-EPMC6518560 | biostudies-literature
Project description:Background:While circulation of respiratory syncytial virus (RSV) results in high rates of hospitalization, particularly among young children and elderly individuals, little is known about the role of different age groups in propagating annual RSV epidemics. Methods:We evaluate the roles played by individuals in different age groups during RSV epidemics in the United States between 2001 and 2012, using the previously defined relative risk (RR) statistic estimated from the hospitalization data from the Healthcare Cost and Utilization Project. Transmission modeling was used to examine the robustness of our inference method. Results:Children aged 3-4 years and 5-6 years each had the highest RR estimate for 5 of 11 seasons included in this study, with RSV hospitalization rates in infants being generally higher during seasons when children aged 5-6 years had the highest RR estimate. Children aged 2 years had the highest RR estimate during one season. RR estimates in infants and individuals aged ≥11 years were mostly lower than in children aged 1-10 years. Highest RR values aligned with groups for which vaccination had the largest impact on epidemic dynamics in most model simulations. Conclusions:Our estimates suggest the prominent relative roles of children aged ≤10 years (particularly among those aged 3-6 years) in propagating RSV epidemics. These results, combined with further modeling work, should help inform RSV vaccination policies.
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Project description:With the rise of the second pandemic wave of the novel influenza A (H1N1) virus in the current season in the Northern Hemisphere, pandemic plans are being carefully re-evaluated, particularly for the strategic use of antiviral drugs. The recent emergence of oseltamivir-resistant in treated H1N1 patients has raised concerns about the prudent use of neuraminidase inhibitors for both treatment of ill individuals and post-exposure prophylaxis of close contacts.We extended an established population dynamical model of pandemic influenza with treatment to include post-exposure prophylaxis of close contacts. Using parameter estimates published in the literature, we simulated the model to evaluate the combined effect of treatment and prophylaxis in minimizing morbidity and mortality of pandemic infections in the context of transmissible drug resistance.We demonstrated that, when transmissible resistant strains are present, post-exposure prophylaxis can promote the spread of resistance, especially when combined with aggressive treatment. For a given treatment level, there is an optimal coverage of prophylaxis that minimizes the total number of infections (final size) and this coverage decreases as a higher proportion of infected individuals are treated. We found that, when treatment is maintained at intermediate levels, limited post-exposure prophylaxis provides an optimal strategy for reducing the final size of the pandemic while minimizing the total number of deaths. We tested our results by performing a sensitivity analysis over a range of key model parameters and observed that the incidence of infection depends strongly on the transmission fitness of resistant strains.Our findings suggest that, in the presence of transmissible drug resistance, strategies that prioritize the treatment of only ill individuals, rather than the prophylaxis of those suspected of being exposed, are most effective in reducing the morbidity and mortality of the pandemic. The impact of post-exposure prophylaxis depends critically on the treatment level and the transmissibility of resistant strains and, therefore, enhanced surveillance and clinical monitoring for resistant mutants constitutes a key component of any comprehensive plan for antiviral drug use during an influenza pandemic.
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Project description:Assessing and managing the impact of large-scale epidemics considering only the individual risk and severity of the disease is exceedingly difficult and could be extremely expensive. Economic consequences, infrastructure and service disruption, as well as the recovery speed, are just a few of the many dimensions along which to quantify the effect of an epidemic on society's fabric. Here, we extend the concept of resilience to characterize epidemics in structured populations, by defining the system-wide critical functionality that combines an individual's risk of getting the disease (disease attack rate) and the disruption to the system's functionality (human mobility deterioration). By studying both conceptual and data-driven models, we show that the integrated consideration of individual risks and societal disruptions under resilience assessment framework provides an insightful picture of how an epidemic might impact society. In particular, containment interventions intended for a straightforward reduction of the risk may have net negative impact on the system by slowing down the recovery of basic societal functions. The presented study operationalizes the resilience framework, providing a more nuanced and comprehensive approach for optimizing containment schemes and mitigation policies in the case of epidemic outbreaks.
| S-EPMC5789872 | biostudies-other
Project description:We assess how presymptomatic infection affects predictability of infectious disease epidemics. We focus on whether or not a major outbreak (i.e. an epidemic that will go on to infect a large number of individuals) can be predicted reliably soon after initial cases of disease have appeared within a population. For emerging epidemics, significant time and effort is spent recording symptomatic cases. Scientific attention has often focused on improving statistical methodologies to estimate disease transmission parameters from these data. Here we show that, even if symptomatic cases are recorded perfectly, and disease spread parameters are estimated exactly, it is impossible to estimate the probability of a major outbreak without ambiguity. Our results therefore provide an upper bound on the accuracy of forecasts of major outbreaks that are constructed using data on symptomatic cases alone. Accurate prediction of whether or not an epidemic will occur requires records of symptomatic individuals to be supplemented with data concerning the true infection status of apparently uninfected individuals. To forecast likely future behavior in the earliest stages of an emerging outbreak, it is therefore vital to develop and deploy accurate diagnostic tests that can determine whether asymptomatic individuals are actually uninfected, or instead are infected but just do not yet show detectable symptoms.
| S-EPMC4821482 | biostudies-literature