Factors affecting infectious disease- Agent Flashcards
Facultative pathogenic agents are helped by predisposing factors.
T
Stenoxen agents have a wide host range.
F
Euryxen agents have a wide host range
T
An euryxen agent can infect several host species
T
There is no minimum number of agents necessary to infection, because they can
replicate in the host
F
Mutations generally result decrease of the virulence.
T
Immunogenicity of the different agents is different
T
There is a minimum number of each agent that is necessary to infect animals
T
A minimum amount of bacteria or viruses is needed to a successful infection
T
Virulence of an agent can be characterized with its LD50 value
T
Pathogenicity means the ability of the agent to cause disease.
T
Virulence means the level of pathogenicity.
T
The amount of the agent does not influence the outcome of the infection, since it can
replicate in the host.
F
In the case of optimal way of infection the least amount of agent can cause disease.
T
The virulence of the agents is connected to virulence factors.
T
Virulence is a stable characteristic of an agent.
F
The way of the infection (entrance of the agents) can influence its outcome.
T
Virulence of a bacterium or virus can be changed spontaneously.
T
In case of a secondary infection the agent complicates a primary infection.
T
Virulence of a bacterium or virus can be changed.
T
The virulence factors help the agents in causing disease
T
Virulence variants can occur within a bacterium or virus species.
T
Pathogenic variants can occur within a bacterium or virus species.
T
Species specific resistance can be overcome by increasing the number of agents.
F
Within a pathogenic species no avirulent strains can occur
F
