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Basic reproductive number

Derdei Bichara, Abderrahman Iggidr
We develop a multi-patch and multi-group model that captures the dynamics of an infectious disease when the host is structured into an arbitrary number of groups and interacts into an arbitrary number of patches where the infection takes place. In this framework, we model host mobility that depends on its epidemiological status, by a Lagrangian approach. This framework is applied to a general SEIRS model and the basic reproduction number [Formula: see text] is derived. The effects of heterogeneity in groups, patches and mobility patterns on [Formula: see text] and disease prevalence are explored...
November 17, 2017: Journal of Mathematical Biology
Soumya Banerjee, Alan S Perelson, Melanie Moses
Understanding how quickly pathogens replicate and how quickly the immune system responds is important for predicting the epidemic spread of emerging pathogens. Host body size, through its correlation with metabolic rates, is theoretically predicted to impact pathogen replication rates and immune system response rates. Here, we use mathematical models of viral time courses from multiple species of birds infected by a generalist pathogen (West Nile Virus; WNV) to test more thoroughly how disease progression and immune response depend on mass and host phylogeny...
November 2017: Journal of the Royal Society, Interface
Matthew J Cummings, Barnabas Bakamutumaho, Wan Yang, Joseph F Wamala, John Kayiwa, Nicholas Owor, Barbara Namagambo, Timothy Byaruhanga, Allison Wolf, Julius J Lutwama, Jeffrey Shaman, Max R O'Donnell
In sub-Saharan Africa, little is known about the epidemiology of pandemic-prone influenza viruses in urban settings. Using data from a prospective sentinel surveillance network, we characterized the emergence, epidemiology, and transmission dynamics of 2009 pandemic A/H1N1 influenza (H1N1pdm09) in Kampala, Uganda. After virus introduction via international air travel from England in June 2009, we estimated the basic reproductive number in Kampala to be 1.06-1.13, corresponding to attack rates of 12-22%. We subsequently identified 613 cases of influenza in Kampala from 2009 to 2015, of which 191 (31...
October 30, 2017: American Journal of Tropical Medicine and Hygiene
Eduardo Martins Netto, Andres Moreira-Soto, Celia Pedroso, Christoph Höser, Sebastian Funk, Adam J Kucharski, Alexandra Rockstroh, Beate M Kümmerer, Gilmara Souza Sampaio, Estela Luz, Sara Nunes Vaz, Juarez Pereira Dias, Fernanda Anjos Bastos, Renata Cabral, Thomas Kistemann, Sebastian Ulbert, Xavier de Lamballerie, Thomas Jaenisch, Oliver J Brady, Christian Drosten, Manoel Sarno, Carlos Brites, Jan Felix Drexler
During 2015 to 2016, Brazil reported more Zika virus (ZIKV) cases than any other country, yet population exposure remains unknown. Serological studies of ZIKV are hampered by cross-reactive immune responses against heterologous viruses. We conducted serosurveys for ZIKV, dengue virus (DENV), and Chikungunya virus (CHIKV) in 633 individuals prospectively sampled during 2015 to 2016, including microcephaly and non-microcephaly pregnancies, HIV-infected patients, tuberculosis patients, and university staff in Salvador in northeastern Brazil using enzyme-linked immunosorbent assays (ELISAs) and plaque reduction neutralization tests...
November 14, 2017: MBio
C Guinat, T Porphyre, A Gogin, L Dixon, D U Pfeiffer, S Gubbins
Mortality data are routinely collected for many livestock and poultry species, and they are often used for epidemiological purposes, including estimating transmission parameters. In this study, we infer transmission rates for African swine fever virus (ASFV), an important transboundary disease of swine, using mortality data collected from nine pig herds in the Russian Federation with confirmed outbreaks of ASFV. Parameters in a stochastic model for the transmission of ASFV within a herd were estimated using approximate Bayesian computation...
November 9, 2017: Transboundary and Emerging Diseases
Mattia Manica, Giorgio Guzzetta, Piero Poletti, Federico Filipponi, Angelo Solimini, Beniamino Caputo, Alessandra Della Torre, Roberto Rosà, Stefano Merler
A large chikungunya outbreak is ongoing in Italy, with a main cluster in the Anzio coastal municipality. With preliminary epidemiological data, and a transmission model using mosquito abundance and biting rates, we estimated the basic reproduction number R0 at 2.07 (95% credible interval: 1.47-2.59) and the first case importation between 21 May and 18 June 2017. Outbreak risk was higher in coastal/rural sites than urban ones. Novel transmission foci could occur up to mid-November.
November 2017: Euro Surveillance: Bulletin Européen sur les Maladies Transmissibles, European Communicable Disease Bulletin
Gilberto González-Parra, Hana M Dobrovolny, Diego F Aranda, Benito Chen-Charpentier, Rafael Antonio Guerrero Rojas
Globally, rotavirus is the most common cause of diarrhea in children younger than 5 years of age, however, a quantitative understanding of the infection dynamics is still lacking. In this paper, we present the first study to extract viral kinetic parameters for in vitro rotavirus infections in the REH cell tumor line. We use a mathematical model of viral kinetics to extract parameter values by fitting the model to data from rotavirus infection of REH cells. While accurate results for some of the parameters of the mathematical model were not achievable due to its global non-identifiability, we are able to quantify approximately the time course of the infection for the first time...
November 3, 2017: Virus Research
Nicolas P Rebuli, N G Bean, J V Ross
A novel outbreak will generally not be detected until such a time that it has become established. When such an outbreak is detected, public health officials must determine the potential of the outbreak, for which the basic reproductive numberR0 is an important factor. However, it is often the case that the resulting estimate of R0 is positively-biased for a number of reasons. One commonly overlooked reason is that the outbreak was not detected until such a time that it had become established, and therefore did not experience initial fade out...
November 1, 2017: Theoretical Population Biology
Getachew Teshome Tilahun, Oluwole Daniel Makinde, David Malonza
We propose and analyze a compartmental nonlinear deterministic mathematical model for the typhoid fever outbreak and optimal control strategies in a community with varying population. The model is studied qualitatively using stability theory of differential equations and the basic reproductive number that represents the epidemic indicator is obtained from the largest eigenvalue of the next-generation matrix. Both local and global asymptotic stability conditions for disease-free and endemic equilibria are determined...
2017: Computational and Mathematical Methods in Medicine
Karen Pazol, Cheryl L Robbins, Lindsey I Black, Katherine A Ahrens, Kimberly Daniels, Anjani Chandra, Anjel Vahratian, Lorrie E Gavin
PROBLEM/CONDITION: Receipt of key preventive health services among women and men of reproductive age (i.e., 15-44 years) can help them achieve their desired number and spacing of healthy children and improve their overall health. The 2014 publication Providing Quality Family Planning Services: Recommendations of CDC and the U.S. Office of Population Affairs (QFP) establishes standards for providing a core set of preventive services to promote these goals. These services include contraceptive care for persons seeking to prevent or delay pregnancy, pregnancy testing and counseling, basic infertility services for those seeking to achieve pregnancy, sexually transmitted disease (STD) services, and other preconception care and related preventive health services...
October 27, 2017: MMWR. Surveillance Summaries: Morbidity and Mortality Weekly Report. Surveillance Summaries
Elissa J Schwartz, Naveen K Vaidya, Karin S Dorman, Susan Carpenter, Robert H Mealey
Understanding the dynamics of acute viral infection is crucial for developing strategies to prevent and control infection. In this study, lentiviral dynamics in a host without adaptive immunity were examined in order to determine kinetic parameters of infection and quantify the effect of neutralizing antibodies in preventing infection, using mathematical modeling of data from equine infectious anemia virus (EIAV) infection of horses with severe combined immunodeficiency (SCID). Estimated parameters were used to calculate the basic reproductive number and virus doubling time and found that the rate that antibodies neutralized virus was ~18 times greater than the virus clearance rate...
October 19, 2017: Virology
Gunnar Dalen, Amira Rachah, Håvard Nørstebø, Ynte H Schukken, Yrjö T Gröhn, John W Barlow, Olav Reksen
The development of reliable models for transmission of intramammary infections (IMI) is the subject of extensive research. Such models are useful to enhance the identification and understanding of factors that affect pathogen-specific IMI dynamics. Longitudinal transmission models are valuable for predicting infection outbreak risks, quantifying the effectiveness of response tactics, and performing response planning. In this work, we focused on modeling Corynebacterium spp. by using a compartmental model. Previous investigations have considered modeling the transmission dynamics of several bacterial pathogens, but not Corynebacterium spp...
October 18, 2017: Journal of Dairy Science
So Young Lee, Kyungsu Kang
Toxicological evaluation is crucial for understanding the effects of chemicals on living organisms in basic and applied biological science fields. A non-mammalian soil round worm, Caenorhabditis elegans, is a valuable model organism for toxicology studies due to its convenience and lack of animal ethics issues compared with mammalian animal systems. In this protocol, a detailed procedure of toxicological evaluation of chemicals in C. elegans is described. A clinical anticancer drug, etoposide, which targets human topoisomerase II and inhibits DNA replication of human cancer cells, was selected as a model testing chemical...
October 5, 2017: Journal of Visualized Experiments: JoVE
Junli Liu, Zhenguo Bai, Tailei Zhang
In this paper, we propose a periodic SIS epidemic model with time delay and transport-related infection in a patchy environment. The basic reproduction number R0 is derived which determines the global dynamics of the model system: if R0 < 1, the disease-free periodic state is globally attractive while there exists at least one positive periodic state and the disease persists if R0 > 1. Numerical simulations are performed to confirm the analytical results and to explore the dependence of R0 on the transport-related infection parameters and the amplitude of fluctuations...
October 12, 2017: Journal of Theoretical Biology
Yu Zhao, Mingtao Li, Sanling Yuan
Tuberculosis (TB), an air-borne infectious disease, is a major public-health problem in China. The reported number of the active tuberculosis cases is about one million each year. The morbidity data for 2005-2012 reflect that the difference in morbidity based on age group is significant, thus the role of age-structure on the transmission of TB needs to be further developed. In this work, based on the reported data and the observed morbidity characteristics, we propose a susceptible-exposed-infectious-recovered (SEIR) epidemic model with age groupings, involving three categories: children, the middle-aged, and senior to investigate the role of age on the transmission of tuberculosis in Mainland China from 2005 to 2016...
October 7, 2017: International Journal of Environmental Research and Public Health
Carles Barril, Àngel Calsina, Jordi Ripoll
A spatially structured linear model of the growth of intestinal bacteria is analysed from two generational viewpoints. Firstly, the basic reproduction number associated with the bacterial population, i.e. the expected number of daughter cells per bacterium, is given explicitly in terms of biological parameters. Secondly, an alternative quantity is introduced based on the number of bacteria produced within the intestine by one bacterium originally in the external media. The latter depends on the parameters in a simpler way and provides more biological insight than the standard reproduction number, allowing the design of experimental procedures...
November 2017: Bulletin of Mathematical Biology
Sanyi Tang, Qinling Yan, Wei Shi, Xia Wang, Xiaodan Sun, Pengbo Yu, Jianhong Wu, Yanni Xiao
China is now experiencing major public health challenges caused by air pollution. Few studies have quantified the dynamics of air pollution and its impact on the risk of respiratory infection. We conducted an integrated data analysis to quantify the association among air quality index (AQI), meteorological variables and respiratory infection risk in Shaanxi province of China in the period of November 15th, 2010 to November 14th, 2016. Our analysis illustrated a statistically significantly positive correlation between the number of influenza-like illness (ILI) cases and AQI, and the respiratory infection risk has increased progressively with increased AQI with a time lag of 0-3 days...
September 28, 2017: Environmental Pollution
B R Morin, A P Kinzig, S A Levin, C A Perrings
Does society benefit from encouraging or discouraging private infectious disease-risk mitigation? Private individuals routinely mitigate infectious disease risks through the adoption of a range of precautions, from vaccination to changes in their contact with others. Such precautions have epidemiological consequences. Private disease-risk mitigation generally reduces both peak prevalence of symptomatic infection and the number of people who fall ill. At the same time, however, it can prolong an epidemic. A reduction in prevalence is socially beneficial...
September 29, 2017: EcoHealth
Sunhwa Choi, Eunok Jung, Bo Youl Choi, Young Joo Hur, Moran Ki
BACKGROUND: Effective countermeasures against emerging infectious diseases require an understanding of transmission rate and basic reproduction number (R0). The R0 for severe acute respiratory syndrome (SARS) is generally considered to be >1, whereas that for Middle East respiratory syndrome (MERS) is considered to be <1. However, this does not explain the large-scale outbreaks of MERS that occurred in Kingdom of Saudi Arabia (KSA) and South Korean hospitals. AIM: To estimate R0 in nosocomial outbrea ks of MERS...
September 25, 2017: Journal of Hospital Infection
Suresh Ramaswamy, William H Walker, Paula Aliberti, Rahil Sethi, Gary R Marshall, Alyxzandria Smith, Seyedmehdi Nourashrafeddin, Alicia Belgorosky, Uma R Chandran, Mark P Hedger, Tony M Plant
STUDY QUESTION: What is the genetic landscape within the testis of the juvenile rhesus monkey (Macaca mulatta) that underlies the decision of undifferentiated spermatogonia to commit to a pathway of differentiation when puberty is induced prematurely by exogenous LH and FSH stimulation? SUMMARY ANSWER: Forty-eight hours of gonadotrophin stimulation of the juvenile monkey testis resulted in the appearance of differentiating B spermatogonia and the emergence of 1362 up-regulated and 225 down-regulated testicular mRNAs encoding a complex network of proteins ranging from enzymes regulating Leydig cell steroidogenesis to membrane receptors, and from juxtacrine and paracrine factors to transcriptional factors governing spermatogonial stem cell fate...
October 1, 2017: Human Reproduction
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