AVIAN FLU: MODELING AND IMPLICATIONS FOR CONTROL

2014 ◽  
Vol 22 (01) ◽  
pp. 151-175 ◽  
Author(s):  
MAIA MARTCHEVA
Keyword(s):  
Epidemiological Data ◽  
Equation System ◽  
Current Control ◽  
Control Measures ◽  
Cumulative Number ◽  
Human Influenza ◽  
Human Influenza Virus ◽  
Pandemic Strain ◽  
H5n1 Avian Influenza ◽  
Efficient Control

At present, H5N1 avian influenza (AI) is a zoonotic disease where the transmission to humans occurs from infected domestic birds. Since 2003, more than 500 people have been infected and nearly 60% of them have died. If the H5N1 virus becomes efficiently human-to-human transmittable, a pandemic will occur with potentially high mortality. A mathematical model of AI, which involves human influenza, is introduced to better understand the complex epidemiology of AI and the emergence of a pandemic strain. Demographic and epidemiological data on birds and humans are used for the parameterization of the model. The differential equation system faithfully projects the cumulative number of H5N1 human cases and captures the dynamics of the yearly cases. The model is used to rank the efficacy of the current control measures used to prevent the emergence of a pandemic strain. We find that culling without re-population and vaccination are the two most efficient control measures each giving 22% decrease in the number of H5N1 infected humans for each 1% change in the affected parameters (μb, νb for culling and βb, νb for vaccination). Control measures applied to humans, such as wearing protective gear, are not very efficient, giving less than 1% decrease in the number of H5N1 infected humans for each 1% decrease in βY, the bird-to-human transmission coefficient of H5N1. Furthermore, we find that should a pandemic strain emerge, it will invade, possibly displacing the human influenza virus in circulation at that time. Moreover, higher prevalence levels of human influenza will obstruct the invasion capabilities of the pandemic H5N1 strain. This effect is not very pronounced, as we find that 1% increase in human influenza prevalence will decrease the invasion capabilities of the pandemic strain with 0.006%.

scholarly journals Data-Based Analysis, Modelling and Forecasting of the COVID-19 outbreak

2020 ◽  
Author(s):  
Cleo Anastassopoulou ◽  
Lucia Russo ◽  
Athanasios Tsakris ◽  
Constantinos Siettos
Keyword(s):  
Lower Bound ◽  
Total Population ◽  
Case Fatality ◽  
Epidemiological Data ◽  
Control Measures ◽  
Suspected Case ◽  
Cumulative Number ◽  
Case Fatality Ratio ◽  
Average Value ◽  
Reported Data

AbstractSince the first suspected case of coronavirus disease-2019 (COVID-19) on December 1st, 2019, in Wuhan, Hubei Province, China, a total of 40,235 confirmed cases and 909 deaths have been reported in China up to February 10, 2020, evoking fear locally and internationally. Here, based on the publicly available epidemiological data for Hubei, China from January 11 to February 10, 2020, we provide estimates of the main epidemiological parameters. In particular, we provide an estimation of the case fatality and case recovery ratios, along with their 90% confidence intervals as the outbreak evolves. On the basis of a Susceptible-Infected-Recovered-Dead (SIDR) model, we provide estimations of the basic reproduction number (R0), and the per day infection mortality and recovery rates. By calibrating the parameters of the SIRD model to the reported data, we also attempt to forecast the evolution of the of the outbreak at the epicenter three weeks ahead, i.e. until February 29. As the number of infected individuals, especially of those with asymptomatic or mild courses, is suspected to be much higher than the official numbers, which can be considered only as a subset of the actual numbers of infected and recovered cases in the total population, we have repeated the calculations under a second scenario that considers twenty times the number of confirmed infected cases and forty times the number of recovered, leaving the number of deaths unchanged. Based on the reported data, the expected value of R0 as computed considering the period from the 11th of January until the 18th of January, using the official counts of confirmed cases was found to be ∼4.6, while the one computed under the second scenario was found to be ∼3.2. Thus, based on the SIRD simulations, the estimated average value of R0 was found to be ∼ 2.6 based on confirmed cases and2 based on the second scenario. Our forecasting flashes a note of caution for the presently unfolding outbreak in China. Based on the official counts for confirmed cases, the simulations suggest that the cumulative number of infected could reach 180,000 (with lower bound of 45,000) by February 29. Regarding the number of deaths, simulations forecast that on the basis of the up to the 10th of February reported data, the death toll might exceed 2,700 (as a lower bound) by February 29. Our analysis further reveals a significant decline of the case fatality ratio from January 26 to which various factors may have contributed, such as the severe control measures taken in Hubei, China (e.g. quarantine and hospitalization of infected individuals), but mainly because of the fact that the actual cumulative numbers of infected and recovered cases in the population most likely are much higher than the reported ones. Thus, in a scenario where we have taken twenty times the confirmed number of infected and forty times the confirmed number of recovered cases, the case fatality ratio is around ∼ 0.15% in the total population. Importantly, based on this scenario, simulations suggest a slow down of the outbreak in Hubei at the end of February.

scholarly journals The impact of COVID-19 pandemic on influenza transmission: molecular and epidemiological evidence

2021 ◽  
Author(s):  
Leon K Tran ◽  
Dai-Wei Huang ◽  
Nien-Kung Li ◽  
Julia Palacios ◽  
Hsiao-Han Chang ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Control Measures ◽  
Human Influenza ◽  
Epidemiological Evidence ◽  
Human Influenza Virus ◽  
Molecular Sequences ◽  
Influenza Transmission ◽  
Personal Behavior ◽  
The Impact

To quantify the impact of COVID-19-related control measures on the spread of human influenza virus, we analyzed case numbers, viral molecular sequences, personal behavior data, and policy stringency data from various countries, and found consistent evidence of decrease in influenza incidence after the emergence of COVID-19.

scholarly journals Assessing the Global Tendency of COVID-19 Outbreak

2020 ◽  
Author(s):  
Qinghe Liu ◽  
Zhicheng Liu ◽  
Junkai Zhu ◽  
Yuhao Zhu ◽  
Deqiang Li ◽  
...  
Keyword(s):  
United States ◽  
Western Europe ◽  
Clustering Algorithm ◽  
The United States ◽  
Current Control ◽  
Control Measures ◽  
Cumulative Number ◽  
Global Epidemic ◽  
Number Of Patients ◽  
Diagnosis Rate

ABSTRACTCOVID-19 is now widely spreading around the world as a global pandemic. In this report, we estimate the global tendency of COVID-19 and analyze the associated global epidemic risk, given that the status quo is continued without further measures being taken.The results show that the global R0, excluding China, is estimated to be 2.49 (95% CI: 2.15 – 2.92). The United States, Germany, Italy and Spain have peak values over 100,000. According to dynamical model and cluster analysis, we category the globe into four type regional epicenters of the outbreak: Southeast Asia extending southward to Oceania, the Middle East, Western Europe and North America. Among them, Western Europe will become the major center of the outbreak. The peak values in Germany, Italy and Spain are estimated to be 105,903, 127,283 and 152,539, respectively. The United States is the country with the most serious outbreak trend. Based on the current control measures by Mar. 27, 2020, the peak value in the United States will reach 400,892. Above all, if the current control measures are maintained, the cumulative number of patients worldwide will be 1,442,523 (95% CI: 1,052,577 – 8,981,440). We also estimated the diagnosis rate, recovery rate and infection degree of each country or region, and use clustering algorithm to retrieve countries or regions with similar epidemic characteristics. Different suggestions are proposed for countries or regions in different clusters.

scholarly journals Phylogenetic Complexity of Morphologically Identified Anopheles squamosus in Southern Zambia

Insects ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 146
Author(s):  
Jordan Hoffman ◽  
Ilinca Ciubotariu ◽  
Limonty Simubali ◽  
Twig Mudenda ◽  
William Moss ◽  
...  
Keyword(s):  
Phylogenetic Relationships ◽  
Catchment Area ◽  
Control Strategies ◽  
Light Trap ◽  
Current Control ◽  
Control Measures ◽  
Morphological Identification ◽  
The Past ◽  
Blood Meal Source ◽  
Residual Malaria Transmission

Despite dramatic reductions in malaria cases in the catchment area of Macha Hospital, Choma District, Southern Province in Zambia, prevalence has remained near 1–2% by RDT for the past several years. To investigate residual malaria transmission in the area, this study focuses on the relative abundance, foraging behavior, and phylogenetic relationships of Anopheles squamosus specimens. In 2011, higher than expected rates of anthropophily were observed among “zoophilic” An. squamosus, a species that had sporadically been found to contain Plasmodium falciparum sporozoites. The importance of An. squamosus in the region was reaffirmed in 2016 when P. falciparum sporozoites were detected in numerous An. squamosus specimens. This study analyzed Centers for Disease Control (CDC) light trap collections of adult mosquitoes from two collection schemes: one performed as part of a reactive-test-and-treat program and the second performed along a geographical transect. Morphological identification, molecular verification of anopheline species, and blood meal source were determined on individual samples. Data from these collections supported earlier studies demonstrating An. squamosus to be primarily exophagic and zoophilic, allowing them to evade current control measures. The phylogenetic relationships generated from the specimens in this study illustrate the existence of well supported clade structure among An. squamosus specimens, which further emphasizes the importance of molecular identification of vectors. The primarily exophagic behavior of An. squamosus in these collections also highlights that indoor vector control strategies will not be sufficient for elimination of malaria in southern Zambia.

scholarly journals Analysis and prediction of the coronavirus disease epidemic in China based on an individual-based model

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Zuiyuan Guo ◽  
Dan Xiao
Keyword(s):  
Reproduction Number ◽  
Control Measures ◽  
Cumulative Number ◽  
Individual Based Model ◽  
Whole Process ◽  
Coordinate Descent Algorithm ◽  
Initial Stage ◽  
The Government ◽  
Prevention And Control Measures ◽  
And Control

AbstractWe established a stochastic individual-based model and simulated the whole process of occurrence, development, and control of the coronavirus disease epidemic and the infectors and patients leaving Hubei Province before the traffic was closed in China. Additionally, the basic reproduction number (R0) and number of infectors and patients who left Hubei were estimated using the coordinate descent algorithm. The median R0 at the initial stage of the epidemic was 4.97 (95% confidence interval [CI] 4.82–5.17). Before the traffic lockdown was implemented in Hubei, 2000 (95% CI 1982–2030) infectors and patients had left Hubei and traveled throughout the country. The model estimated that if the government had taken prevention and control measures 1 day later, the cumulative number of laboratory-confirmed patients in the whole country would have increased by 32.1%. If the lockdown of Hubei was imposed 1 day in advance, the cumulative number of laboratory-confirmed patients in other provinces would have decreased by 7.7%. The stochastic model could fit the officially issued data well and simulate the evolution process of the epidemic. The intervention measurements nationwide have effectively curbed the human-to-human transmission of severe acute respiratory syndrome coronavirus 2.

scholarly journals Timing and Route of Contamination of Patient Rooms With Healthcare-Associated Pathogens

2020 ◽  
Vol 41 (S1) ◽  
pp. s412-s412
Author(s):  
Sarah Redmond ◽  
Jennifer Cadnum ◽  
Basya Pearlmutter ◽  
Natalia Pinto Herrera ◽  
Curtis Donskey
Keyword(s):  
Acute Care Hospital ◽  
Current Control ◽  
Pathogen Transmission ◽  
Control Measures ◽  
Effective Control ◽  
Portable Devices ◽  
Care Hospital ◽  
Spa Typing ◽  
Persistent Problem ◽  
Healthcare Associated

Background: Transmission of healthcare-associated pathogens such as Clostridioides difficile and methicillin-resistant Staphylococcus aureus (MRSA) is a persistent problem in healthcare facilities despite current control measures. A better understanding of the routes of pathogen transmission is needed to develop effective control measures. Methods: We conducted an observational cohort study in an acute-care hospital to identify the timing and route of transfer of pathogens to rooms of newly admitted patients with negative MRSA nares results and no known carriage of other healthcare-associated pathogens. Rooms were thoroughly cleaned and disinfected prior to patient admission. Interactions of patients with personnel and portable equipment were observed, and serial cultures for pathogens were collected from the skin of patients and from surfaces, including those observed to come in contact with personnel and equipment. For MRSA, spa typing was used to determine relatedness of patient and environmental isolates. Results: For the 17 patients enrolled, 1 or more environmental cultures became positive for MRSA in rooms of 10 patients (59%), for C. difficile in rooms of 2 patients (12%) and for vancomycin-resistant enterococci (VRE) in rooms of 2 patients (12%). The patients interacted with an average of 2.4 personnel and 0.6 portable devices per hour of observation. As shown in Figure 1, MRSA contamination of the floor occurred rapidly as personnel entered the room. In a subset of patients, MRSA was subsequently recovered from patients’ socks and bedding and ultimately from the high-touch surfaces in the room (tray table, call button, bedrail). For several patients, MRSA isolates recovered from the floor had the same spa type as isolates subsequently recovered from other sites (eg, socks, bedding, and/or high touch surfaces). The direct transfer of healthcare-associated pathogens from personnel or equipment to high-touch surfaces was not detected. Conclusions: Healthcare-associated pathogens rapidly accumulate on the floor of patient rooms and can be transferred to the socks and bedding of patients and to high-touch surfaces. Healthcare facility floors may be an underappreciated source of pathogen dissemination not addressed by current infection control measures.Funding: NoneDisclosures: None

scholarly journals Human Cystic Echinococcosis in Lebanon: A Retrospective Study and Molecular Epidemiology

2021 ◽  
Author(s):  
Gaelle Joanny ◽  
Maria Grazia Cappai ◽  
Francesca Nonnis ◽  
Claudia Tamponi ◽  
Giorgia Dessì ◽  
...  
Keyword(s):  
Echinococcus Granulosus ◽  
Cystic Echinococcosis ◽  
Epidemiological Data ◽  
Sensu Stricto ◽  
Control Measures ◽  
Mediterranean Countries ◽  
High Gene ◽  
Human Infections ◽  
And Control ◽  
Human Cystic Echinococcosis

Abstract Purpose Human cystic echinococcosis (CE) is a zoonotic parasitic disease that constitutes a public health challenge and a socio-economic burden in endemic areas worldwide. No specific surveillance system of CE infections in humans exists in Lebanon. The incidence and trends over time have not been documented. The current study aimed to assess the demographic and epidemiologic features of human CE surgical cases over a 14-year period in the five main regions of Lebanon. Methods From 2005 to 2018, a total of 894 surgically confirmed cases of hydatidosis were recorded from five anatomy and pathology laboratories. Results The mean annual surgical incidence was 1.23/100,000 inhabitants. Over the span of these years, the incidence increased from 0.53 to 1.94 cases/100,000 inhabitants in 2005 and 2018, respectively. CE is present in Lebanon with an uneven distribution from one region to the other with higher prevalence in Bekaa (29.0%), a rural area where sheep raising is widespread. Human CE cases were more common in females (60.1%) than in males (39.9%) and a high burden of infection was reported for the age group of 30–39 years. Besides, 66.7% of the cases expressed only liver complications whereas, 20.5% showed predilection towards lungs. The 7.8% of cases presented cysts in other organs, and 1.3% showed multiple localizations. Additionally, predominant involvement of Echinococcus granulosus sensu stricto was recorded in human infections. Comparison of Echinococcus granulosus s.s. populations from different Mediterranean countries also revealed high gene flow among this region and sharing of alleles. Conclusion The current study is a step forward to fill the gap of knowledge for the hydatidosis in Lebanon where the lack of epidemiological data and control measures have resulted in higher incidence of human CE. Graphic Abstract

The occurrence of human influenza virus antibodies in the sera of certain wild species of animal

1970 ◽  
Vol 32 (2-3) ◽  
pp. 286-290 ◽  
Author(s):  
K. F. Shortridge ◽  
G. Belyavin ◽  
D. E. Bidwell
Keyword(s):  
Influenza Virus ◽  
Wild Species ◽  
Human Influenza ◽  
Human Influenza Virus
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