Virulence

virulentavirulenceavirulentbacterial virulencehypervirulentintrinsic virulencenon-virulentnonvirulentpotentially infectiousviral
Virulence is a pathogen's or microbe's ability to infect or damage a host.wikipedia
350 Related Articles

Pathogen

pathogenspathogenicpathogenicity
The pathogenicity of an organism - its ability to cause disease - is determined by its virulence factors.
Pathogenicity is related to virulence in meaning, but some authorities have come to distinguish it as a qualitative term, whereas the latter is quantitative.

Virulence factor

virulence factorsfactorsimmunoevasive
The pathogenicity of an organism - its ability to cause disease - is determined by its virulence factors. The ability of bacteria to cause disease is described in terms of the number of infecting bacteria, the route of entry into the body, the effects of host defense mechanisms, and intrinsic characteristics of the bacteria called virulence factors.
Experimental research, for example, often focuses on creating environments that isolate and identify the role of "niche-specific virulence genes". These are genes that perform specific tasks within specific tissues/places at specific times; the sum total of niche-specific genes is the virus' virulence.

Bacterial effector protein

effector proteinsBacterial effector proteinseffector
Many virulence factors are so-called effector proteins that are injected into the host cells by special secretion machines such as the type 3 secretion system.
Effector proteins are usually critical for virulence.

Horizontal gene transfer

lateral gene transferhorizontal transfergene transfer
Certain bacteria employ mobile genetic elements and horizontal gene transfer.
Horizontal gene transfer is the primary mechanism for the spread of antibiotic resistance in bacteria, and plays an important role in the evolution of bacteria that can degrade novel compounds such as human-created pesticides and in the evolution, maintenance, and transmission of virulence.

Quorum sensing

quorum-sensingQuorum Sensing Inhibitorsquorum signal
Bacteria use quorum sensing to synchronise release of the molecules.
Some common phenotypes include biofilm formation, virulence factor expression, and motility.

Bacteria

bacteriumbacterialEubacteria
The ability of bacteria to cause disease is described in terms of the number of infecting bacteria, the route of entry into the body, the effects of host defense mechanisms, and intrinsic characteristics of the bacteria called virulence factors. Extensively studied model organisms of virulent viruses include virus T4 and other T-even bacteriophages which infect Escherichia coli and a number of related bacteria.
Many types of secretion systems are known and these structures are often essential for the virulence of pathogens, so are intensively studied.

Gene-for-gene relationship

gene-for-geneAvirulenceGuard Hypothesis
In the context of gene for gene systems, often in plants, virulence refers to a pathogen's ability to infect a resistant host.
Because there would be no evolutionary advantage to a pathogen keeping a protein that only serves to have it recognised by the plant, it is believed that the products of Avr genes play an important role in virulence in genetically susceptible hosts.

Helicobacter pylori

H. pyloriantibiotic-resistant ''H. pyloribacteria
pylori'' virulence proteins.

HIV

human immunodeficiency virusHIV-positiveHIV positive
Virulent viruses such as HIV, which causes AIDS, have mechanisms for evading host defenses.
HIV-1 is more virulent and more infective than HIV-2, and is the cause of the majority of HIV infections globally.

Streptococcus pneumoniae

pneumococcusS. pneumoniaepneumococcal
They have a polysaccharide capsule that acts as a virulence factor for the organism; more than 90 different serotypes are known, and these types differ in virulence, prevalence, and extent of drug resistance.

Toxin

toxinstoxicbiotoxin
Toxins produced by microorganisms are important virulence determinants responsible for microbial pathogenicity and/or evasion of the host immune response.

Optimal virulence

the host population might never develop tolerance to the pathogendecreasing virulencevirulence versus transmissibility
According to evolutionary medicine, optimal virulence increases with horizontal transmission (between non-relatives) and decreases with vertical transmission (from parent to child).
One definition of virulence is the host's parasite-induced loss of fitness.

Horizontal transmission

horizontallyhorizontalhorizontal transfer
According to evolutionary medicine, optimal virulence increases with horizontal transmission (between non-relatives) and decreases with vertical transmission (from parent to child).
Because the evolutionary fate of the agent is not tied to reproductive success of the host, horizontal transmission tends to evolve virulence.

Lytic cycle

lyticlytic life cyclelytic stage
The lytic life cycle of virulent bacteriophages is contrasted by the temperate lifecycle of Temperate bacteriophages.
Bacteriophages that only use the lytic cycle are called virulent phages (in contrast to temperate phages).

Virus

virusesviralvirion
Virus virulence factors allow it to replicate, modify host defenses, and spread within the host, and they are toxic to the host.
The relative ability of viruses to cause disease is described in terms of virulence.

Escherichia coli

E. coliE.coliE-coli
Extensively studied model organisms of virulent viruses include virus T4 and other T-even bacteriophages which infect Escherichia coli and a number of related bacteria.
These virulent strains typically cause a bout of diarrhea that is often self-limiting in healthy adults but is frequently lethal to children in the developing world.

Infection

infectious diseaseinfectious diseasesinfections
Some critical disease characteristics that should be evaluated include virulence, distance traveled by victims, and level of contagiousness.

Super-spreader

super-spreaderssuper-spreadingsuperspreaders
Super-spreading events are shaped by multiple factors including a decline in herd immunity, nosocomial infections, virulence, viral load, misdiagnosis, airflow dynamics, immune suppression, and co-infection with another pathogen.

Neurotropic virus

neurotropicneurotropismNeuroinvasive
The term "neurovirulent" is used for viruses such as rabies and herpes simplex which can invade the nervous system and cause disease there.

Shigatoxigenic and verotoxigenic Escherichia coli

enterohemorrhagicEHECenterohemorrhagic ''E. coli
The infectivity or the virulence of an EHEC strain depends on several factors, including the presence of fucose in the medium, the sensing of this sugar and the activation of EHEC pathogenicity island.

Host (biology)

hostintermediate hosthosts
In most other contexts, especially in animal systems, virulence refers to the degree of damage caused by a microbe to its host.

Disease

morbidityillnessdiseases
The pathogenicity of an organism - its ability to cause disease - is determined by its virulence factors.

Noun

nounssubstantiveabstract noun
The noun virulence derives from the adjective virulent.

Adjective

adjectivesadjectivalattributive adjective
The noun virulence derives from the adjective virulent.