On the probability of strain invasion in endemic settings: accounting for individual heterogeneity and control in multi-strain dynamics

Publication date: Available online 6 December 2019Source: Journal of Theoretical BiologyAuthor(s): Michael T. Meehan, Robert C. Cope, Emma S. McBrydeAbstractPathogen evolution is an imminent threat to global health that has warranted, and duly received, considerable attention within the medical, microbiological and modelling communities. Outbreaks of new pathogens are often ignited by the emergence and transmission of mutant variants descended from wild-type strains circulating in the community. In this work we investigate the stochastic dynamics of the emergence of a novel disease strain, introduced into a population in which it must compete with an existing endemic strain. In analogy with past work on single-strain epidemic outbreaks, we apply a branching process approximation to calculate the probability that the new strain becomes established. As expected, a critical determinant of the survival prospects of any invading strain is the magnitude of its reproduction number relative to that of the background endemic strain. Whilst in most circumstances this ratio must exceed unity in order for invasion to be viable, we show that differential control scenarios can lead to less-fit novel strains invading populations hosting a fitter endemic one. This analysis and the accompanying findings will inform our understanding of the mechanisms that have led to past instances of successful strain invasion, and provide valuable lessons for thwarting future drug-resistant strain incursion...
Source: Journal of Theoretical Biology - Category: Biology Source Type: research

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CONCLUSION: The amotosalen/UVA PR system inactivated high titers of infectious YFV-17D in PC. This PR technology could reduce the risk of YFV TTI and help secure PC supplies in areas experiencing YFV outbreaks where massive vaccination campaigns are required. PMID: 31957887 [PubMed - as supplied by publisher]
Source: Transfusion - Category: Hematology Authors: Tags: Transfusion Source Type: research
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Source: Vaccine - Category: Allergy & Immunology Authors: Tags: Vaccine Source Type: research
Publication date: Available online 21 December 2019Source: Antiviral ResearchAuthor(s): Melanie Rissmann, Franziska Stoek, Matthew J. Pickin, Martin H. GroschupAbstractRift Valley fever phlebovirus (RVFV) is an arthropod-borne virus that has caused substantial epidemics throughout Africa and in the Arabian Peninsula. The virus can cause severe disease in livestock and humans and therefore the control and prevention of viral outbreaks is of utmost importance. The epidemiology of RVFV has some particular characteristics. Unexpected and significant epidemics have been observed in spatially and temporally divergent patterns ac...
Source: Antiviral Therapy - Category: Virology Source Type: research
Abstract Rift Valley fever phlebovirus (RVFV) is an arthropod-borne virus that has caused substantial epidemics throughout Africa and in the Arabian Peninsula. The virus can cause severe disease in livestock and humans and therefore the control and prevention of viral outbreaks is of utmost importance. The epidemiology of RVFV has some particular characteristics. Unexpected and significant epidemics have been observed in spatially and temporally divergent patterns across the African continent. Sudden epidemics in previously unaffected areas are followed by periods of long-term apparent absence of virus and sudden,...
Source: Antiviral Research - Category: Virology Authors: Tags: Antiviral Res Source Type: research
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Source: Antiviral Therapy - Category: Virology Source Type: research
Abstract Sporadic human Zika virus (ZIKV) infections have been recorded in Africa and Asia since the 1950s. Major epidemics occurred only after ZIKV emerged in the Pacific islands and spread to the Americas. Specific biological determinants of the explosive epidemic nature of ZIKV have not been identified. Phylogenetic studies revealed incongruence in ZIKV placement in relation to Aedes-borne dengue viruses (DENV) and Culex-borne flaviviruses. We hypothesized that this incongruence reflects interspecies recombination resulting in ZIKV evasion of cross-protective T-cell immunity. We investigated ZIKV phylogenetic i...
Source: Antiviral Research - Category: Virology Authors: Tags: Antiviral Res Source Type: research
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Source: Medecine et Maladies Infectieuses - Category: Infectious Diseases Tags: Med Mal Infect Source Type: research
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Source: Virus Research - Category: Virology Authors: Tags: Virus Res Source Type: research
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Source: American Journal of Perinatology - Category: Perinatology & Neonatology Authors: Tags: Commentary Source Type: research
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Source: Infection, Genetics and Evolution - Category: Genetics & Stem Cells Authors: Tags: Infect Genet Evol Source Type: research
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