Microbiology of disease Flashcards
Infection
the invasion and/or colonisation by and subsequent multiplication of pathogenic organisms in a body part or tissue which can produce subsequent tissue injury and progression to overt disease through a variety of cellular/toxic mechanisms
Enzootic
a disease regularly affects animals in a particular district/season.
Endemic
(for humans but used anyway)
regularly found in a particular group or in a particular area.
Latency
the pathogen goes inert in animals; reactivation may occur if the pathogen is switched back on.
Often relates to viruses.
Carriage
the animal tolerates the pathogen without disease. The carrier animal is a reservoir for infection as it may shed pathogens.
Reservoir of infection
any animal/human/environment in which an infectious agent normally lives and mutliplies.
Acute infection
pathogen is cleared shortly after infection
Chronic infection
pathogen is detectable for the lifetime of the host
Latent infection
Infectious agents disappears within the animal but can be reactivated by a number of factors.
What descriptive term for disease does this graph show?
Acute infection
What descriptive term for disease does this graph show?
Chronic infection
What descriptive term for disease does this graph show?
Latent infection
Endogenous pathogen
already on the animal; may suddenly cause disease due to changes in the organism/host or opportunity arising.
Exogenous pathogens
transferred to the animal from another source; not already present on the animal.
Method of transmission of pathogens
- Vertical transmission
- Horizontal transmission
- Sexual transmission
- Food-borne
- Vector-borne
- Iatrogenic
Vertical transmission
transmission of pathogen/disease from parent to offspring
Horizontal transmission
transmission of a pathogen within a group
Commensals
bacteria or fungi that exist on or in hosts without causing disease. Some are very important to the animal’s health (e.g. gut bacteria of ruminants)
Commensalism
the relationship between two species whereby one benefits from the association, whereas the other neither benefits nor suffers.
Includes bacteria, fungi and protozoa.
Opportunistic pathogen
normally benign organism which causes infections when given the chance
–> a commensal in the wrong place
–> when host defences are compromised
