Related Experiment Video
Updated: Jun 19, 2026
08:38
Using a Bacterial Pathogen to Probe for Cellular and Organismic-level Host Responses
Published on: February 22, 2019
Transient virulence of emerging pathogens.
Benjamin M Bolker1, Arjun Nanda, Dharmini Shah
1Department of Biology, University of Florida, Gainesville, FL 32611, USA. bolker@ufl.edu
Journal of the Royal Society, Interface
|October 30, 2009
Summary
Emerging pathogens may become more virulent due to epidemic conditions selecting for higher virulence. This transient selection can significantly increase pathogen virulence during an epidemic, impacting public health.
Area of Science:
- Evolutionary biology
- Epidemiology
- Pathogen dynamics
Background:
- Virulence evolution theories suggest tradeoffs between transmission and pathogen duration.
- Epidemic conditions may favor higher virulence, potentially causing transient peaks early in an outbreak.
- Understanding emerging pathogen virulence is crucial for public health preparedness.
Purpose of the Study:
- To model the epidemiological and evolutionary dynamics of emerging pathogens.
- To estimate the potential magnitude and timing of virulence peaks in emerging pathogens.
- To assess the contribution of epidemic-phase selection to pathogen virulence.
Main Methods:
- Developed a simple model of pathogen epidemiological and evolutionary dynamics.
- Used parameter estimates for pathogens like SARS, West Nile virus, and myxomatosis.
- Reviewed literature data on virulence tradeoff curves and genetic variation for selected pathogens.
Main Results:
- A model was developed to simulate virulence evolution in emerging pathogens.
- Pathogens with moderate evolvability, high transmissibility, and high equilibrium virulence could double virulence during epidemics.
- Epidemic-phase selection can substantially contribute to the virulence of emerging pathogens.
Conclusions:
- Transient selection during epidemics can significantly increase the virulence of emerging pathogens.
- Further data on virulence tradeoff curves and genetic variance are needed to fully evaluate virulence evolution scenarios.
- This mechanism highlights the dynamic nature of pathogen virulence and its potential impact.
More Related Videos
Related Concept Videos
01:28Infectious Diseases and Their Occurrence
Infectious diseases appear in populations through various transmission patterns, influenced by pathogen characteristics, population immunity, environmental conditions, and social behavior. Understanding these patterns is essential for effective public health surveillance and intervention. These categories—sporadic, outbreak, epidemic, pandemic, and endemic—help frame the nature and scope of disease events.Sporadic diseases occur irregularly and infrequently, without a predictable temporal or...
01:20Determinants of Bacterial Pathogenicity and Virulence
Pathogenic bacteria employ a variety of strategies to establish infections, including the secretion of extracellular enzymes that act as potent virulence factors. These enzymes facilitate bacterial colonization of host tissues and help evade immune surveillance. By targeting structural components of host tissues and interfering with immune mechanisms, these enzymes play a pivotal role in disease progression.Extracellular Enzymes Facilitating Tissue Invasion: Several bacterial pathogens secrete...
01:25Colonisation of Pathogens
Pathogen colonization of host tissues is a critical step in the development of infectious diseases. Various pathogenic microorganisms, including bacteria, fungi, viruses, and protozoa, have evolved complex strategies to attach to, invade, and persist within host environments. These mechanisms enable pathogens to establish infections, evade immune responses, and resist antimicrobial treatments.Attachment to Host CellsIn bacteria, colonization typically begins with adherence to host epithelial...
01:16Transduction
Among the three main modes of HGT—transformation, conjugation, and transduction—transduction is unique in that it is mediated by bacteriophages, or bacterial viruses.Transduction occurs in two ways. Generalized transduction occurs during the lytic cycle of a bacteriophage infection. In this process, bacteriophages infect bacterial cells, replicate within them, and ultimately cause cell lysis, releasing newly assembled virions. Occasionally, random fragments of the bacterial genome are...
00:57Viral Recombination
Cells are sometimes infected by more than one virus at once. When two viruses disassemble to expose their genomes for replication in the same cell, similar regions of their genomes can pair together and exchange sequences in a process called recombination. Alternatively, viruses with segmented genomes can swap segments in a process called reassortment.
01:28Regulation of Bacterial Virulence
Pathogenic bacteria employ a range of regulatory mechanisms to modulate the expression of virulence genes in response to environmental and host-derived signals. These mechanisms ensure that virulence factors are expressed only under favorable conditions, thereby optimizing infection and survival strategies.Mechanisms of Virulence RegulationKey regulatory strategies include:Two-Component Systems: These consist of a membrane-bound sensor kinase and a cytoplasmic response regulator. Environmental...