Identifying the number of unreported cases in SIR epidemic models

2019 ◽  
Vol 37 (2) ◽  
pp. 243-261 ◽  
Author(s):  
A Ducrot ◽  
P Magal ◽  
T Nguyen ◽  
G F Webb
Keyword(s):  
New York ◽  
Seasonal Influenza ◽  
Influenza Epidemic ◽  
Sir Epidemic Model ◽  
Sir Epidemic ◽  
Sir Epidemic Models ◽  
Relationship Of ◽  
The Relationship ◽  
Case Data ◽  
Epidemic Diseases

Abstract An SIR epidemic model is analysed with respect to the identification of its parameters and initial values, based upon reported case data from public health sources. The objective of the analysis is to understand the relationship of unreported cases to reported cases. In many epidemic diseases the reported cases are a small fraction of the unreported cases. This fraction can be estimated by the identification of parameters for the model from reported case data. The analysis is applied to the Hong Kong seasonal influenza epidemic in New York City in 1968–1969.

scholarly journals Using Unstated Cases to Correct for COVID-19 Pandemic Outbreak and Its Impact on Easing the Intervention for Qatar

Biology ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 463
Author(s):  
Narjiss Sallahi ◽  
Heesoo Park ◽  
Fedwa El Mellouhi ◽  
Mustapha Rachdi ◽  
Idir Ouassou ◽  
...  
Keyword(s):  
Public Health ◽  
A Priori ◽  
Epidemiological Models ◽  
Sir Epidemic Model ◽  
Gulf Region ◽  
Epidemiological Modeling ◽  
Public Health Policies ◽  
Sir Epidemic ◽  
The Impact ◽  
Case Data

Epidemiological Modeling supports the evaluation of various disease management activities. The value of epidemiological models lies in their ability to study various scenarios and to provide governments with a priori knowledge of the consequence of disease incursions and the impact of preventive strategies. A prevalent method of modeling the spread of pandemics is to categorize individuals in the population as belonging to one of several distinct compartments, which represents their health status with regard to the pandemic. In this work, a modified SIR epidemic model is proposed and analyzed with respect to the identification of its parameters and initial values based on stated or recorded case data from public health sources to estimate the unreported cases and the effectiveness of public health policies such as social distancing in slowing the spread of the epidemic. The analysis aims to highlight the importance of unreported cases for correcting the underestimated basic reproduction number. In many epidemic outbreaks, the number of reported infections is likely much lower than the actual number of infections which can be calculated from the model’s parameters derived from reported case data. The analysis is applied to the COVID-19 pandemic for several countries in the Gulf region and Europe.

scholarly journals Using excess deaths and testing statistics to determine COVID-19 mortalities

2021 ◽  
Author(s):  
Lucas Böttcher ◽  
Maria R. D’Orsogna ◽  
Tom Chou
Keyword(s):  
New York ◽  
New York City ◽  
Disease Prevalence ◽  
Statistical Testing ◽  
Biased Sampling ◽  
Mortality Data ◽  
Sir Epidemic Model ◽  
Excess Death ◽  
Sir Epidemic ◽  
Excess Deaths

AbstractFactors such as varied definitions of mortality, uncertainty in disease prevalence, and biased sampling complicate the quantification of fatality during an epidemic. Regardless of the employed fatality measure, the infected population and the number of infection-caused deaths need to be consistently estimated for comparing mortality across regions. We combine historical and current mortality data, a statistical testing model, and an SIR epidemic model, to improve estimation of mortality. We find that the average excess death across the entire US from January 2020 until February 2021 is 9$$\%$$ % higher than the number of reported COVID-19 deaths. In some areas, such as New York City, the number of weekly deaths is about eight times higher than in previous years. Other countries such as Peru, Ecuador, Mexico, and Spain exhibit excess deaths significantly higher than their reported COVID-19 deaths. Conversely, we find statistically insignificant or even negative excess deaths for at least most of 2020 in places such as Germany, Denmark, and Norway.

Population variation in Sorghum halepense, Johnson grass, at the northern limits of its range

1984 ◽  
Vol 62 (9) ◽  
pp. 1781-1790 ◽  
Author(s):  
S. I. Warwick ◽  
B. K. Thompson ◽  
L. D. Black
Keyword(s):  
New York ◽  
Dry Weight ◽  
Population Variation ◽  
Sorghum Halepense ◽  
Johnson Grass ◽  
Allocation Patterns ◽  
Cultivated Species ◽  
Relationship Of ◽  
The Relationship ◽  
Enzyme Patterns

Thirteen populations of Sorghum halepense, Johnson grass, were sampled from fields in Ontario, Canada, and Ohio and New York, United States. Only four of these populations were reported to overwinter as rhizomes. The morphology, phenology, resource allocation patterns, and growth of seedling and mature plants of the overwintering and the non-overwintering populations were compared. Field-collected specimens from the nonoverwintering populations had wider culms and leaves and larger seeds and inflorescences. Analysis of material grown in a 5-month greenhouse trial indicated similar differences. Greenhouse plants from the nonoverwintering populations were also characterized by greater percent emergence, larger and faster growing seedlings, earlier flowering, larger culms and seeds, greater reproductive dry weight per plant, and about 1/10th the rhizome dry weight of overwintering plants. Differences between populations within a biotype were evident for both biotypes, although there was little within-population variation, except in rhizome production, where certain individuals of some nonoverwintering populations did not produce extended rhizomes. Among the five enzymes which were examined electrophoretically, only one, phosphoglucomutase (PGM), showed variable isozyme patterns. No differences in enzyme patterns were apparent between the overwintering and the nonoverwintering biotypes. The relationship of the nonoverwintering populations to the cultivated species, Sorghum bicolor and S. almum, an introgressant between S. halepense and S. bicolor, is discussed.

Evolution and Catholicism: A Few Modest Proposals

Horizons ◽  
2008 ◽  
Vol 35 (2) ◽  
pp. 203-227
Author(s):  
James L. Heft
Keyword(s):  
New York ◽  
New York Times ◽  
School Science ◽  
Science And Religion ◽  
High School Science ◽  
Public High School ◽  
Catholic Theology ◽  
Science Classes ◽  
Relationship Of ◽  
The Relationship

ABSTRACTDuring 2006, two events, one involving mainly Protestants and the other Catholics, triggered widespread debate on evolution and Christianity. The Dover, Pennsylvania case focused on whether intelligent design (ID) should be taught alongside evolution in public high school science classes; a New York Times Op-Ed by Cardinal Schönborn of Austria argued that Catholics should reject neo-Darwinianism. Once again, these debates raise the important issue of the relationship of science and religion, and more specifically, science and Catholicism, and call for further reflection on how Catholic theology should conceive of its role in an age still dominated by science.

scholarly journals Bifurcation analysis of an SIR epidemic model with saturated treatment function

2021 ◽  
Author(s):  
Phuc Ngo
Keyword(s):  
Epidemic Models ◽  
Stable Node ◽  
Sir Epidemic Model ◽  
Treatment Rate ◽  
Globally Asymptotically Stable ◽  
Sir Epidemic ◽  
Treatment Function ◽  
Sir Epidemic Models ◽  
Saturated Treatment ◽  
Disease Free

In this thesis we investigate the dynamics and bifurcation of SIR epidemic models with horizontal and vertical transmissions and saturated treatment rate. It is proved that such SIR epidemic models always have positive disease free equilibria and also have three positive epidemic equilibria. The ranges of the parameters related in the model were found under which the equilibria of the models are positive. By applying the qualitative theory of planar systems, it is shown the disease free equilibria is a saddle, stable node and globally asymptotically stable. Furthermore, it is also shown that the interior equilibria are saddle, saddle node or saddle point.

scholarly journals Knowledge of AIDS and self-efficacy to high-risk sexual practices among Lebanese males in New York

2002 ◽  
Vol 08 (06) ◽  
pp. 732-748
Author(s):  
K. Z. Awad
Keyword(s):  
New York ◽  
High Risk ◽  
Self Efficacy ◽  
Small Sample ◽  
Sexual Practices ◽  
Convenience Sample ◽  
Significant Relationships ◽  
Aids Knowledge ◽  
Relationship Of ◽  
The Relationship

The relationship of AIDS knowledge and self-efficacy to high-risk sexual practices among Lebanese males in NewYork was examined. Self-administered questionnaires were completed by a convenience sample. Relationships between AIDS-knowledge and self-efficacy and high-risk sexual practices for the 25 homosexual men were rarely significant, probably because of the small sample. The 261 heterosexual participants had statistically significant relationships between AIDS-knowledge and 9 high-risk sexual practices and between self-efficacy and 18 high-risk sexual practices. For heterosexuals, and to a lesser degree for homosexuals, high-risk sexual practices increased as drug-related behaviours and sex with prostitutes increased.

scholarly journals Using excess deaths and testing statistics to improve estimates of COVID-19 mortalities

2021 ◽  
Author(s):  
Lucas Böttcher ◽  
Maria R. D’Orsogna ◽  
Tom Chou
Keyword(s):  
New York ◽  
New York City ◽  
Disease Prevalence ◽  
Statistical Testing ◽  
Biased Sampling ◽  
Mortality Data ◽  
Sir Epidemic Model ◽  
Excess Death ◽  
Sir Epidemic ◽  
Excess Deaths

Factors such as non-uniform definitions of mortality, uncertainty in disease prevalence, and biased sampling complicate the quantification of fatality during an epidemic. Regardless of the employed fatality measure, the infected population and the number of infection-caused deaths need to be consistently estimated for comparing mortality across regions. We combine historical and current mortality data, a statistical testing model, and an SIR epidemic model, to improve estimation of mortality. We find that the average excess death across the entire US is 13% higher than the number of reported COVID-19 deaths. In some areas, such as New York City, the number of weekly deaths is about eight times higher than in previous years. Other countries such as Peru, Ecuador, Mexico, and Spain exhibit excess deaths significantly higher than their reported COVID-19 deaths. Conversely, we find negligible or negative excess deaths for part and all of 2020 for Denmark, Germany, and Norway.

scholarly journals Phase portraits of SIR epidemic models with vertical transmissions and linear treatment

2021 ◽  
Author(s):  
Marvin Hoti
Keyword(s):  
Epidemic Models ◽  
Phase Portraits ◽  
Sir Epidemic ◽  
Sir Epidemic Models ◽  
Epidemic Diseases

Susceptible-infective-removed epidemic models with horizontal and vertical transmissions and linear treatment rates are investigated. All the ranges of the parameters involved in the models for the infection-free equilibrium and the epidemic equilibrium to be positive are found. Like the previous results on the models without vertical transmissions or the linear treatments, we study stability of these equilibria. The novelty is that we justify that these positive equilibria are stable focuses or stable nodes under suitable conditions on the parameters. These results provide more detailed descriptions of behaviours of the epidemic diseases near the equilibria. Our results will exhibit the effect of the vertical transmissions and the linear treatment rates on the epidemic models. Some simulations results are provided to understand the phase portraits near the equilibria.

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