Animal Microbiology Flashcards
What are the three major sources of microbes in production systems?
Environment, other animals, and the animal itself.
Where in the environment can microorganisms be found?
Soil, water sources, bedding materials, floors, walls, and farm equipment.
How can other animals serve as a source of microorganisms?
Microorganisms can be acquired from different species serving as intermediate hosts or from the same species (infected/sick animals or sub-clinically infected animals).
What role does the animal itself play as a source of microorganisms?
Animals have normal flora or microbiota that can act as opportunistic pathogens causing disease under certain circumstances.
How do environmental microorganisms affect animals?
Animals exposed to environmental microorganisms might develop diseases such as environmental mastitis, depending on their health status and immunity.
How do other animals transmit microorganisms to livestock?
Microorganisms can be transmitted from a different species (intermediate hosts) or from animals within the same species through direct contact or sub-clinical infections.
What are normal flora or microbiota in animals?
They are the normal population of microorganisms that provide colonization protection and aid in functions like digestion.
How can normal flora become pathogenic?
Under certain conditions, normal flora can act as opportunistic pathogens causing diseases like mastitis or abscesses.
Does the presence of an infectious agent always indicate disease?
No, the presence of an infectious agent does not necessarily indicate the presence or development of disease.
What does the term “multifactorial approach” mean in disease control?
It means considering the interactions between the host, the microorganism, and the environment to control disease.
What is the epidemiologic triangle?
It is a model illustrating the interaction between the host, the microorganism, and the environment in the development of disease.
What is the difference between association and causation in epidemiology?
An association between two variables does not always mean that one causes the other; causation implies a direct cause-and-effect relationship.
Give an example of association not implying causation
An increase in ice cream consumption may be associated with an increase in drowning deaths, but it does not mean ice cream consumption causes drowning.
How can pathogens (microbes) enter the body?
Pathogens can enter through different ports including the skin, respiratory tract, gastrointestinal tract, genitourinary tract, conjunctiva, mammary gland, and umbilicus.
What are some ports of entry for microorganisms into the body?
Skin, respiratory tract, gastrointestinal tract, genitourinary tract, conjunctiva, mammary gland, umbilicus.
What happens when a pathogen enters a healthy, immunocompetent animal?
An immune response is triggered, and the infection may be controlled or lead to different outcomes: recovery, persistent infection, or death.
What are the possible outcomes once an animal is infected?
The outcomes include recovery (clearing the organism), persistent infection (chronic, latent, shedding or not shedding), and death.
Define vertical transmission of microorganisms.
Vertical transmission occurs from mother to offspring across the placenta, in the birth canal, or in colostrum/milk.
Define horizontal transmission of microorganisms
Horizontal transmission includes any other type of transmission either directly or indirectly between individuals.
What is the difference between clinical and subclinical disease?
Clinical disease shows recognizable signs (e.g., coughing, diarrhea), while subclinical disease does not show signs but may result in a drop in production and requires specialized testing to detect.
What is the significance of subclinically infected animals in disease transmission?
Subclinically infected animals may not show signs of disease but can be a silent source of infection, playing a crucial role in spreading the disease.
What is a carrier state in animals?
A carrier state occurs when an animal harbors a microorganism without showing clinical signs but can transmit the pathogen to others.
Give an example of a carrier state in animals.
Salmonella in dairy cattle is an example where the animal remains clinically normal but can intermittently or permanently spread the microorganism.
