Chapter 14 Flashcards
symbiosis
the relationship between normal microbiota and the host
opportunistic pathogens
do not cause disease in their normal habitat in a healthy person but may do so in a different enviroment
mutualism and example
both organisms benefit. ex: E.Coli in the intestines
commensalism and example
one organism benefits and another is unaffected. ex: S. Epidermis on the skin
What is another name for a nosocomial infection? What are they? Where do you get them?
Healthcare-associated infection (HAI). These are infections that patients get while receiving treatment for other conditions. You get them in hospitals, nursing homes, clinics, in-home health care enviroment
What are the most common types of HAIs? How do you prevent them?
Now, MRSA, S. aureus, and C. dificile. Aseptic techniques, careful handling of contaminated material, frequent handwashing
What are Koch’s postulates?
the disease has to have the same pathogen then
What are the exceptions to the postulates?
some microorganisms cannot be cultured on artificial media, some diseases (pneumonia, peritonitis, meningitis), some pathogens infect a number of different organs or tissues and cause very different diseases or symptoms
Incidence
the number of people in a population who develop a disease during a particular time period. indicated spread of disease
Epidemic
many people in a given area acquire a certain disease in a short period of time (influenza). Pandemic is a worldwide epidemic
Endemic
if a disease is constantly present (common cold)
Pandemic
epidemic that is actively spreading to multiple regions across the globe
difference between pandemic and epidemic?
Epidemic is large, it is also contained and expected to spread. Pandemic is international and out of control
Sporadic
if a disease occurs only occasionally
What is a focal infection? What does it usually start out as?
When a local infection enteres the blood or lymph system and spreads to other parts of the body. Theystart as systemic infections
What is herd immunity? How does it increase?
Many immune people present in a community. It increases by vaccinations
Septicemia
sepsis resulting from pathogens in the bloodstream
Bacteremia
presence of bacteria in the blood
Viremia
presence of viruses in the blood
What is a reservoir of infection? Give some examples.
A source of organisms where an infection and live and multiply. Examples are humans, animals, soil, and water
Define fomite. Give examples.
objects that are likely to carry infections. Examples are tissue, towel, money
Acute
one that develops rapidly, but only lasts a short time
Chronic
develops more slowly and the body reactions are often less sevre but it is continuous for long periods of time
Primary Infections
a acute infection that causes the initial illness
WHat 4 pathogens cause primary infections?
Viruses, bacteria, fungi, parasites
Secondary Infection
caused by a pathogen after a primary infection has weakened the body’s defenses
Define symptoms
changes in body function such as pain and malaise (a vague feeling of body discomfort)
Define signs and examples
objective changes. Examples: lesions, swelling, fever, paralysis
What is an emerging infectious disease (EID)? Where do they come from? How do they form?
EID- are new or changing diseases that show an increase in incidence in the recent past or potentioal increase in the near future. Can come from virus, bacterium, fungus, protozoan. They form by mutation of a previous infection or are transferred by international vehicles
Transmission of a disease
how diseases can move from one place to another
Contact Transmission
the spread of a disease by direct contact, indirect contact, or droplet transmission
Direct Contact Transmission
(person to person) is the direct transmission of an agent by physical contact between the disease source and the host
Indirect Contact Transmission
involves nonliving objects such as a glass, a tissue, towel money
Droplet Transmission
microbes are spread in mucus droplets
Vehicle transmission
inanimate reservoirs such as food, water, or blood can also transmist disease. Can also be on blood or other body fluids, drugs, or IV fluids
Vector Transmission
transmitted by blood-feeding animals like mosquitos, ticks, and fleas
What is a latent infection
one in which the pathogen i inactive for a time but then becomes active to produce symptoms
What are the stages of an infectious disease? Describe each stage
1) Incubation. The time from exposure to a infectious disease until to the onset symptoms.
2) Prodromal: the period after incubation and before symptoms of infection occur
3) Illness: The time when a person shows symptoms of an infection disease
4) Decline: The immune system sets up in effective defense against the pathogens and the numbers of infectious particles decreases
5) Convalescence: Symproms resolve and a person can return to normal
