Chapter 14- Infection and Epidemiology Flashcards
The microorganisms that happen to live with us (without normally causing disease) OR colonize the surface of our body are called our
normal flora / normal microbiota
2 main groups of normal flora
- Resident microbiota
- Transient microbiota
Resident microbiota
- Been there since we were born
- Harmless under normal conditions (non-pathogenic)
Resident microbiota only lives on the ____ of our body (external and internal surfaces like upper resp.). On the other hand, our internal tissues are _____ which means it’s ___/__ ___ ____
Resident microbiota only lives on the surface of our body (external and internal surfaces like upper resp.). On the other hand, our internal tissues are microbe-free which means it’s axenic (pure) / no bacteria exist
External body surfaces, where our Resident Microbiota can be found, include our ___ and _____ (the mucous membrane that covers the exposed surface of the eye and the interior of eyelid).
External body surfaces, where our Resident Microbiota can be found, include our skin and conjunctiva (the mucous membrane that covers the exposed surface of the eye and the interior of eyelid).
Internal body surfaces, where our Resident Microbiota can be found, include the linings of our…
Internal body surfaces, where our Resident Microbiota can be found, include the linings of our nose, mouth, throat, intestinal tract, vagina, and the urethra
Transient Microbiota are only _____ and do not persist in body due to 3 things:
temporary
1. Elimination by body’s defense cells
2. Hygiene
3. Competition from other microbe
Most microbial species that form our Transient Microbiota are harmless, but a few of them are ______ making transient microbiota potentially dangerous
pathogenic
Eyes/skin
Staph
Nose/throat
Strep
G.I (gastrointestinal tract)
E.coli, Lactobacillus
Most of our Resident Microbiota can actually benefit us by a phenomenon called ______ ______(1)
_____ _____(1) is a way for the members of our Resident Microbiota to protect us from these intruders. Microbial antagonism involves _____ between our Resident Microbiota and the invading pathogens. One consequence of such competition is that our Resident Microbiota can protect the host by ______ any invading pathogens coming from outside the human body from establishing their ______
Microbial antagonism is a way for the members of our Resident Microbiota to protect us from these intruders. Microbial antagonism involves competition between our Resident Microbiota and the invading pathogens. One consequence of such competition is that our Resident Microbiota can protect the host by preventing any invading pathogens coming from outside the human body from establishing their residence
What effect might broad-spectrum antibiotics have>
They could kill the beneficial resident microbiota
Example of a Microbial antagonist
Lactobacillus
(These bacteria are also known as lactic acid bacteria. Lactic acid bacteria are nonpathogenic and are usually referred as beneficial bacteria in the human body.)
Resident Microbiota normally __ ___ cause disease.
But under certain conditions, some members of our Resident Microbiota can become harmful and cause disease when the proper “_______” arises. These microorganisms are known as _______ _____
Resident Microbiota normally do not cause disease.
But under certain conditions, some members of our Resident Microbiota can become harmful and cause disease when the proper “opportunity” arises. These microorganisms are known as opportunistic pathogens.
What conditions turn our Resident Microbiota to an opportunistic pathogen?
- Immune suppression
- Stressful conditions
- Introduction of resident microbiota into unusual location
The relationship between Resident Microbiota AND the human host is called
Symbiosis
Symbiosis is when
two organisms live together
3 kinds of symbiotic relationships:
commensalism, mutualism, and parasitism
Commensalism
Benefits microbe, no harm to host
Ex: mites on eyelashes
Mutualism
Benefits microbe, benefits the host
Ex: E.coli
Parasitism
Benefits microbe, harms the host
Ex: tapeworm
There’s an offset of parasitism called _____ in which there is..
Amensalism: no benefit to microbe, but the host is still harmed
If the pathogenic microorganism is not a normal microbiota the question is where is the pathogen normally found?
Reservoir
Every pathogen must have at least one reservoir. A reservoir is the ___ of a pathogen or the____ ____ of a pathogen. A reservoir is a place for the pathogen to survive, multiply (reproduce), and to stay before and after infecting a host. Some pathogens have more than one reservoir.
Every pathogen must have at least one reservoir. A reservoir is the source of a pathogen or the primary habitat of a pathogen. A reservoir is a place for the pathogen to survive, multiply (reproduce), and to stay before and after infecting a host. Some pathogens have more than one reservoir.
3 primary reservoirs:
Human reservoir
Animal reservoir
Nonliving/environmental reservoir
The majority of infections are from ____ ____ due to
Human reservoirs due to temp. and species specificity
There are also people who are apparently healthy but are carrying the pathogen and capable of transmitting it to others. They are classified as _______ _____
Asymptomatic carriers
There are three types of asymptomatic carriers:
- Incubation carriers: not yet showing signs
- Convalescent carriers: active stages of recovery
- Chronic carriers: recovered but still shedding
Zoonoses
Diseases that spread from another animal host to humans
Zoonoses is acquired through various routes:
- Direct contact with animals or their waste
- Eating affected animals
- Blood-sucking anthropods
Both wild and domestic animals can also be reservoirs for some human pathogens. The animal may or may not be affected by the microorganism. Typically the human is considered a _____ ___ ____. This means that once in the human it will not be spread from human to human or even back to the animal from which it contacted the pathogen.
Dead End Host
Dead End Host basically means that we’re
not going to transmit it after contracting the disease
Examples of animal reservoirs
Influenza
Rabies
Salmonellosis
Influenza (ex. animal reservoirs and symptomatic or not)
Pigs, birds, horses
Symptomatic
Rabies (animal reservoirs and symptomatic or not)
Bats, skunks, coyotes, etc.
Symptomatic
Salmonellosis
Poultry and reptiles
Asymptomatic
Environmental Reservoirs-
Some human pathogens are able to survive and reproduce for long periods of time in ______reservoirs such as…
Environmental Reservoirs-
Some human pathogens are able to survive and reproduce for long periods of time in nonliving reservoirs such as soil, water, and food
Environmental Reservoirs-
Keep in mind, the condition in the soil is not as ideal as the human body. Some human pathogens can survive in the soil for years by forming ______
Keep in mind, the condition in the soil is not as ideal as the human body. Some human pathogens can survive in the soil for years by forming endospores
A critical stage of any disease development process is for the pathogen to be able to leave its reservoir and enter the body of a host, this is known as the _______
Human pathogens can enter the body of the host at particular locations called the ____ ___ ____
A critical stage of any disease development process is for the pathogen to be able to leave its reservoir and enter the body of a host, this is known as the transmission
Human pathogens can enter the body of the host at particular locations called the portals of entry
Common portals of entry
Skin, Mucous Membranes, Placenta, and Parenteral (blood)
3 major modes of transmission
contact, vehicle, and vector transmissions
Types of contact transmission
Direct contact transmission
Indirect contact transmission
Droplet transmission
Direct contact transmission
spread by direct physical contact between one person and another person such as by touching, kissing, or sexual intercourse (horizontal transmission)