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  1. Article ; Online: Global dynamics of a compartmental model to assess the effect of transmission from deceased.

    Barua, Saumen / Dénes, Attila

    Mathematical biosciences

    2023  Volume 364, Page(s) 109059

    Abstract: During several epidemics, transmission from deceased people significantly contributed to disease spread, but mathematical analysis of this transmission has not been seen in the literature numerously. Transmission of Ebola during traditional burials was ... ...

    Abstract During several epidemics, transmission from deceased people significantly contributed to disease spread, but mathematical analysis of this transmission has not been seen in the literature numerously. Transmission of Ebola during traditional burials was the most well-known example; however, there are several other diseases, such as hepatitis, plague or Nipah virus, that can potentially be transmitted from disease victims. This is especially true in the case of serious epidemics when healthcare is overwhelmed and the operative capacity of the health sector is diminished, such as seen during the COVID-19 pandemic. We present a compartmental model for the spread of a disease with an imperfect vaccine available, also considering transmission from deceased infected in general. The global dynamics of the system are completely described by constructing appropriate Lyapunov functions. To support our analytical results, we perform numerical simulations to assess the importance of transmission from the deceased, considering the data collected from three infectious diseases, Ebola virus disease, COVID-19, and Nipah fever.
    MeSH term(s) Humans ; Epidemiological Models ; Hemorrhagic Fever, Ebola/epidemiology ; Pandemics ; COVID-19/epidemiology
    Language English
    Publishing date 2023-08-22
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 1126-5
    ISSN 1879-3134 ; 0025-5564
    ISSN (online) 1879-3134
    ISSN 0025-5564
    DOI 10.1016/j.mbs.2023.109059
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: Mathematical Modeling of SARS-CoV-2 Transmission between Minks and Humans Considering New Variants and Mink Culling.

    Ibrahim, Mahmoud A / Dénes, Attila

    Tropical medicine and infectious disease

    2023  Volume 8, Issue 8

    Abstract: We formulated and studied mathematical models to investigate control strategies for the outbreak of the disease caused by SARS-CoV-2, considering the transmission between humans and minks. Two novel models, namely SEIR and SVEIR, are proposed to ... ...

    Abstract We formulated and studied mathematical models to investigate control strategies for the outbreak of the disease caused by SARS-CoV-2, considering the transmission between humans and minks. Two novel models, namely SEIR and SVEIR, are proposed to incorporate human-to-human, human-to-mink, and mink-to-human transmission. We derive formulas for the reproduction number R0 for both models using the next-generation matrix technique. We fitted our model to the daily number of COVID-19-infected cases among humans in Denmark as an example, and using the best-fit parameters, we calculated the values of R0 to be 1.58432 and 1.71852 for the two-strain and single-strain models, respectively. Numerical simulations are conducted to investigate the impact of control measures, such as mink culling or vaccination strategies, on the number of infected cases in both humans and minks. Additionally, we investigated the possibility of the mutated virus in minks being transmitted to humans. Our results indicate that to control the disease and spread of SARS-CoV-2 mutant strains among humans and minks, we must minimize the transmission and contact rates between mink farmers and other humans by quarantining such individuals. In order to reduce the virus mutation rate in minks, culling or vaccination strategies for infected mink farms must also be implemented. These measures are essential in managing the spread of SARS-CoV-2 and its variants, protecting public health, and mitigating the potential risks associated with human-to-mink transmission.
    Language English
    Publishing date 2023-08-03
    Publishing country Switzerland
    Document type Journal Article
    ISSN 2414-6366
    ISSN (online) 2414-6366
    DOI 10.3390/tropicalmed8080398
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  3. Article: Global dynamics of a compartmental model for the spread of Nipah virus.

    Barua, Saumen / Dénes, Attila

    Heliyon

    2023  Volume 9, Issue 9, Page(s) e19682

    Abstract: Nipah virus, which originated in South-East Asia is a bat-borne virus causing Nipah virus infection in humans. This emerging infectious disease has become one of the most alarming threats to public health due to its periodic outbreaks and extremely high ... ...

    Abstract Nipah virus, which originated in South-East Asia is a bat-borne virus causing Nipah virus infection in humans. This emerging infectious disease has become one of the most alarming threats to public health due to its periodic outbreaks and extremely high mortality rate. We establish and study a novel SIRS model to describe the dynamics of Nipah virus transmission, considering human-to-human as well as zoonotic transmission from bats and pigs as well as loss of immunity. We determine the basic reproduction number which can be obtained as the maximum of three threshold parameters corresponding to various ways of disease transmission and determining in which of the three species the disease becomes endemic. By constructing appropriate Lyapunov functions, we completely describe the global dynamics of our model depending on these threshold parameters. Numerical simulations are shown to support our theoretical results and assess the effect of various intervention measures.
    Language English
    Publishing date 2023-09-06
    Publishing country England
    Document type Journal Article
    ZDB-ID 2835763-2
    ISSN 2405-8440
    ISSN 2405-8440
    DOI 10.1016/j.heliyon.2023.e19682
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  4. Article: A mathematical model for the spread of Varroa mites in honeybee populations: two simulation scenarios with seasonality.

    Ibrahim, Mahmoud A / Dénes, Attila

    Heliyon

    2022  Volume 8, Issue 9, Page(s) e10648

    Abstract: We formulate and study a mathematical model for a honeybee colony infected ... ...

    Abstract We formulate and study a mathematical model for a honeybee colony infected with
    Language English
    Publishing date 2022-09-13
    Publishing country England
    Document type Journal Article
    ZDB-ID 2835763-2
    ISSN 2405-8440
    ISSN 2405-8440
    DOI 10.1016/j.heliyon.2022.e10648
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  5. Article ; Online: A mathematical model for the spread of Varroa mites in honeybee populations: two simulation scenarios with seasonality

    Ibrahim, Mahmoud A. / Dénes, Attila

    Heliyon. 2022 Sept., v. 8, no. 9 p.e10648-

    2022  

    Abstract: We formulate and study a mathematical model for a honeybee colony infected with Varroa mites which describes the parallel phenomena of the spread of both the mites and the virus transmitted by them. We extend our previous model by including infected ... ...

    Abstract We formulate and study a mathematical model for a honeybee colony infected with Varroa mites which describes the parallel phenomena of the spread of both the mites and the virus transmitted by them. We extend our previous model by including infected forager bees and considering model parameters as time-periodic functions. Firstly, we study the autonomous model and show the stability of equilibria. We present two simulation scenarios to study the impact of seasonality on the spread of Varroa mites and the disease they carry. Numerical studies are given to show how the parameter changes might lead to the colony's failure.
    Keywords Varroa ; honey bee colonies ; honey bees ; mathematical models ; viruses ; Varroa mite ; Non-autonomous model ; Seasonality ; Colony failure ; Periodic parameters
    Language English
    Dates of publication 2022-09
    Publishing place Elsevier Ltd
    Document type Article ; Online
    Note Use and reproduction
    ZDB-ID 2835763-2
    ISSN 2405-8440
    ISSN 2405-8440
    DOI 10.1016/j.heliyon.2022.e10648
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  6. Article ; Online: Threshold Dynamics in a Model for Zika Virus Disease with Seasonality.

    Ibrahim, Mahmoud A / Dénes, Attila

    Bulletin of mathematical biology

    2021  Volume 83, Issue 4, Page(s) 27

    Abstract: We present a compartmental population model for the spread of Zika virus disease including sexual and vectorial transmission as well as asymptomatic carriers. We apply a non-autonomous model with time-dependent mosquito birth, death and biting rates to ... ...

    Abstract We present a compartmental population model for the spread of Zika virus disease including sexual and vectorial transmission as well as asymptomatic carriers. We apply a non-autonomous model with time-dependent mosquito birth, death and biting rates to integrate the impact of the periodicity of weather on the spread of Zika. We define the basic reproduction number [Formula: see text] as the spectral radius of a linear integral operator and show that the global dynamics is determined by this threshold parameter: If [Formula: see text] then the disease-free periodic solution is globally asymptotically stable, while if [Formula: see text] then the disease persists. We show numerical examples to study what kind of parameter changes might lead to a periodic recurrence of Zika.
    MeSH term(s) Animals ; Culicidae/physiology ; Culicidae/virology ; Humans ; Models, Biological ; Seasons ; Zika Virus/physiology ; Zika Virus Infection/epidemiology ; Zika Virus Infection/transmission
    Language English
    Publishing date 2021-02-17
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 184905-0
    ISSN 1522-9602 ; 0007-4985 ; 0092-8240
    ISSN (online) 1522-9602
    ISSN 0007-4985 ; 0092-8240
    DOI 10.1007/s11538-020-00844-6
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  7. Article ; Online: Adaptive group testing in a compartmental model of COVID-19

    Tekeli, Tamás / Dénes, Attila / Röst, Gergely

    Mathematical biosciences and engineering : MBE

    2022  Volume 19, Issue 11, Page(s) 11018–11033

    Abstract: Various measures have been implemented around the world to prevent the spread of SARS-CoV-2. A potential tool to reduce disease transmission is regular mass testing of a high percentage of the population, possibly with pooling (testing a compound of ... ...

    Abstract Various measures have been implemented around the world to prevent the spread of SARS-CoV-2. A potential tool to reduce disease transmission is regular mass testing of a high percentage of the population, possibly with pooling (testing a compound of several samples with one single test). We develop a compartmental model to study the applicability of this method and compare different pooling strategies: regular and Dorfman pooling. The model includes isolated compartments as well, from where individuals rejoin the active population after some time delay. We develop a method to optimize Dorfman pooling depending on disease prevalence and establish an adaptive strategy to select variable pool sizes during the course of the epidemic. It is shown that optimizing the pool size can avert a significant number of infections. The adaptive strategy is much more efficient, and may prevent an epidemic outbreak even in situations when a fixed pool size strategy can not.
    MeSH term(s) COVID-19/epidemiology ; Disease Outbreaks ; Epidemiological Models ; Humans ; Prevalence ; SARS-CoV-2
    Language English
    Publishing date 2022-09-20
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2265126-3
    ISSN 1551-0018 ; 1551-0018
    ISSN (online) 1551-0018
    ISSN 1551-0018
    DOI 10.3934/mbe.2022513
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  8. Article: A seasonal model to assess intervention strategies for preventing periodic recurrence of Lassa fever.

    Barua, Saumen / Dénes, Attila / Ibrahim, Mahmoud A

    Heliyon

    2021  Volume 7, Issue 8, Page(s) e07760

    Abstract: Lassa haemorrhagic fever is listed in WHO's Blueprint priority list of diseases and pathogens prioritized for research and development, affecting several hundreds of thousands of people each year. Lassa fever is spread via infected Natal multimammate ... ...

    Abstract Lassa haemorrhagic fever is listed in WHO's Blueprint priority list of diseases and pathogens prioritized for research and development, affecting several hundreds of thousands of people each year. Lassa fever is spread via infected Natal multimammate mice and also through human-to-human contacts and it is a particular threat to pregnant women. Despite its importance, relatively few mathematical models have been established for modelling Lassa fever transmission up to now. We establish and study a new compartmental model for Lassa fever transmission including asymptomatic carriers, quarantine and periodic coefficients to model annual weather changes. We determine parameter values providing the best fit to data from Nigerian states Edo and Ondo from 2018-20. We perform uncertainty analysis and PRCC analysis to assess the importance of different parameters and numerical simulations to estimate the possible effects of control measures in eradicating the disease. The results suggest that the most important parameter which might be subject of control measures is death rate of mice, while mouse-to-human and human-to-human transmission rates also significantly influence the number of infected. However, decreasing the latter two parameters seems insufficient to eradicate the disease, while a parallel application of decreasing transmission rates and increasing mouse death rate might be able to stop the epidemic.
    Language English
    Publishing date 2021-08-11
    Publishing country England
    Document type Journal Article
    ZDB-ID 2835763-2
    ISSN 2405-8440
    ISSN 2405-8440
    DOI 10.1016/j.heliyon.2021.e07760
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  9. Article ; Online: Global analysis of a cancer model with drug resistance due to Lamarckian induction and microvesicle transfer.

    Dénes, Attila / Marzban, Sadegh / Röst, Gergely

    Journal of theoretical biology

    2021  Volume 527, Page(s) 110812

    Abstract: Development of resistance to chemotherapy in cancer patients strongly effects the outcome of the treatment. Due to chemotherapeutic agents, resistance can emerge by Darwinian evolution. Besides this, acquired drug resistance may arise via changes in gene ...

    Abstract Development of resistance to chemotherapy in cancer patients strongly effects the outcome of the treatment. Due to chemotherapeutic agents, resistance can emerge by Darwinian evolution. Besides this, acquired drug resistance may arise via changes in gene expression. A recent discovery in cancer research uncovered a third possibility, indicating that this phenotype conversion can occur through the transfer of microvesicles from resistant to sensitive cells, a mechanism resembling the spread of an infectious agent. We present a model describing the evolution of sensitive and resistant tumour cells considering Darwinian selection, Lamarckian induction and microvesicle transfer. We identify three threshold parameters which determine the existence and stability of the three possible equilibria. Using a simple Dulac function, we give a complete description of the dynamics of the model depending on the three threshold parameters. We also establish an agent based model as a spatial version of the ODE model and compare the outputs of the two models. We find that although the ODE model does not provide spatial information about the structure of the tumour, it is capable to determine the outcome in terms of tumour size and distribution of cell types. We demonstrate the possible effects of increasing drug concentration, and characterize the possible bifurcation sequences. Our results show that the presence of microvesicle transfer cannot ruin a therapy that otherwise leads to extinction, however it may doom a partially successful therapy to failure.
    MeSH term(s) Antineoplastic Agents/pharmacology ; Antineoplastic Agents/therapeutic use ; Drug Resistance, Neoplasm/genetics ; Humans ; Neoplasms/drug therapy ; Phenotype ; Selection, Genetic
    Chemical Substances Antineoplastic Agents
    Language English
    Publishing date 2021-06-12
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2972-5
    ISSN 1095-8541 ; 0022-5193
    ISSN (online) 1095-8541
    ISSN 0022-5193
    DOI 10.1016/j.jtbi.2021.110812
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  10. Article ; Online: Modeling the impact of quarantine during an outbreak of Ebola virus disease.

    Dénes, Attila / Gumel, Abba B

    Infectious Disease Modelling

    2019  Volume 4, Page(s) 12–27

    Abstract: The quarantine of people suspected of being exposed to an infectious agent is one of the most basic public health measure that has historically been used to combat the spread of communicable diseases in human communities. This study presents a new ... ...

    Abstract The quarantine of people suspected of being exposed to an infectious agent is one of the most basic public health measure that has historically been used to combat the spread of communicable diseases in human communities. This study presents a new deterministic model for assessing the population-level impact of the quarantine of individuals suspected of being exposed to disease on the spread of the 2014-2015 outbreaks of Ebola viral disease. It is assumed that quarantine is imperfect (i.e., individuals can acquire infection during quarantine). In the absence of quarantine, the model is shown to exhibit global dynamics with respect to the disease-free and its unique endemic equilibrium when a certain epidemiological threshold (denoted by
    Keywords covid19
    Language English
    Publishing date 2019-02-05
    Publishing country China
    Document type Journal Article
    ZDB-ID 3015225-2
    ISSN 2468-0427 ; 2468-2152
    ISSN (online) 2468-0427
    ISSN 2468-2152
    DOI 10.1016/j.idm.2019.01.003
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