Interaction of pathogens
Definitions
Infection: Invasion and replication of microorganisms in the body leading to an abnormal
state.
Incubation period: The period between the entry of the infectious agent into the body and
the appearance of the first symptoms.
Disease: A state of impaired function or health due to the presence of an infectious agent or
a pathologic process. When you develop symptoms.
Latent period: The period between the initial infection in the body and when the patient
becomes infectious to others.
Transmission: When an infectious agent is transferred from one host to another to
potentially spread disease.
Period of Communicability: Timeframe in which an infected individual can transmit the
infectious agent to others.
Two types of transmission
Horizontal
When a disease is transmitted from one individual to another
Within the same population.
Either by direct or indirect contact between the infectious person and the susceptible
individuals.
Vertical
A disease is transmitted from a mother to her offspring during pregnancy, childbirth,
or breastfeeding.
One generation to the next.
E.g., HIV
Virulence factors
What are they: specific characteristics or traits possessed by pathogens that enable them to
cause disease.
measure of its ability to be harmful.
Fimbria/pili
Hair-like structures that are found on the surface of bacteria.
, Made of protein.
Initiates biofilm formation by allowing pathogens to adhere to one another and the
host.
By binding to specific receptors on the host’s surface.
This allows the bacteria to colonize and establish themselves on tissues and organs
without being flushed out by natural defence mechanisms.
Also allows conjugation: gene transfer from the donor to the host by direct contact.
They also Twitch:
T4P
The fimbria can polymerise and depolymerise to become longer and
shorter.
meaning they can drag themselves along the surface of a tissue or organ.
The pathogen throws out the fimbria, sticks to the surface, and
depolymerises dragging itself along.
Biofilms
a complex community of microorganisms that adhere to surfaces and encase within a
self-produced matrix of extracellular polymeric substances (look below).
An environment where pathogens can remain in a favourable environment with
plenty of nutrients without them getting washed away.
Due to a high conc of nutrients, biofilms can become quite large with lots of cells.
Can form on any surface.
And once formed, they are compact and hard to remove.
Definitions
Infection: Invasion and replication of microorganisms in the body leading to an abnormal
state.
Incubation period: The period between the entry of the infectious agent into the body and
the appearance of the first symptoms.
Disease: A state of impaired function or health due to the presence of an infectious agent or
a pathologic process. When you develop symptoms.
Latent period: The period between the initial infection in the body and when the patient
becomes infectious to others.
Transmission: When an infectious agent is transferred from one host to another to
potentially spread disease.
Period of Communicability: Timeframe in which an infected individual can transmit the
infectious agent to others.
Two types of transmission
Horizontal
When a disease is transmitted from one individual to another
Within the same population.
Either by direct or indirect contact between the infectious person and the susceptible
individuals.
Vertical
A disease is transmitted from a mother to her offspring during pregnancy, childbirth,
or breastfeeding.
One generation to the next.
E.g., HIV
Virulence factors
What are they: specific characteristics or traits possessed by pathogens that enable them to
cause disease.
measure of its ability to be harmful.
Fimbria/pili
Hair-like structures that are found on the surface of bacteria.
, Made of protein.
Initiates biofilm formation by allowing pathogens to adhere to one another and the
host.
By binding to specific receptors on the host’s surface.
This allows the bacteria to colonize and establish themselves on tissues and organs
without being flushed out by natural defence mechanisms.
Also allows conjugation: gene transfer from the donor to the host by direct contact.
They also Twitch:
T4P
The fimbria can polymerise and depolymerise to become longer and
shorter.
meaning they can drag themselves along the surface of a tissue or organ.
The pathogen throws out the fimbria, sticks to the surface, and
depolymerises dragging itself along.
Biofilms
a complex community of microorganisms that adhere to surfaces and encase within a
self-produced matrix of extracellular polymeric substances (look below).
An environment where pathogens can remain in a favourable environment with
plenty of nutrients without them getting washed away.
Due to a high conc of nutrients, biofilms can become quite large with lots of cells.
Can form on any surface.
And once formed, they are compact and hard to remove.
