Search results
Results from the WOW.Com Content Network
Virulence is a pathogen's or microorganism's ability to cause damage to a host. In most cases, especially in animal systems, virulence refers to the degree of damage caused by a microbe to its host. [1] The pathogenicity of an organism—its ability to cause disease—is determined by its virulence factors.
Virulence factors (preferably known as pathogenicity factors or effectors in botany) are cellular structures, molecules and regulatory systems that enable microbial pathogens (bacteria, viruses, fungi, and protozoa) to achieve the following: [1] [2] colonization of a niche in the host (this includes movement towards and attachment to host cells ...
Molecular Koch's postulates are a set of experimental criteria that must be satisfied to show that a gene found in a pathogenic microorganism encodes a product that contributes to the disease caused by the pathogen. Genes that satisfy molecular Koch's postulates are often referred to as virulence factors.
A successful pathogen needs to spread to at least one other host, and lower virulence can result in higher transmission rates under some circumstances. Likewise, genetic resistance against the virus can develop in a host population over time. [2] [29] An example of the evolution of virulence in emerging virus is the case of myxomatosis in ...
Pathogenicity is the potential disease-causing capacity of pathogens, involving a combination of infectivity (pathogen's ability to infect hosts) and virulence (severity of host disease). Koch's postulates are used to establish causal relationships between microbial pathogens and diseases.
More specifically, infectivity is the extent to which the pathogen can enter, survive, and multiply in a host. It is measured by the ratio of the number of people who become infected to the total number exposed to the pathogen. [1] Infectivity has been shown to positively correlate with virulence, in plants. This means that as a pathogen's ...
The evolution of virulence in pathogens is a balance between the costs and benefits of virulence to the pathogen. For example, studies of the malaria parasite using rodent [ 3 ] and chicken [ 4 ] models found that there was trade-off between transmission success and virulence as defined by host mortality.
Multiple genetic elements of human-affecting pathogens contribute to the transfer of virulence factors: plasmids, pathogenicity island, prophages, bacteriophages, transposons, and integrative and conjugative elements. [13] [50] Pathogenicity islands and their detection are the focus of several bioinformatics efforts involved in pathogenomics.