infectious disease 1 Flashcards
microbiology
The study of microscopic organisms, such as bacteria, viruses, archaea, fungi and protozoa
infectious disease
natural systems are weakened or altered by ecologic stress
WHY PT NEEDS TO STUDY INFECTIOUS DISEASES?
➢Prevent infection and control of transmission during PT service
signs and symptoms of infectious diseases
- fever, chills, sweating, malaise, and nausea and vomiting
- increased # of leukocytes
- change in types of leukocytes
leukocytosis
Elevated WBC count
leukopenia
decreased WBC
what is the most abundant WBC type
neutrophil
fever
higher than 99.5 F
- hypothalamus is the temperature regulating center [pyrogens cause temp to rise]
signs and symptoms of infectious disease
- Become tachypneic and confused
- Develop hypotension
- Abscess
- Rupture of the abscess and drainage into other tissues can spread the infection
- Rash with fever
- Red streaks (acute lymphangitis)
- Inflamed lymph nodes
- Joint effusion
changes in cell-mediated or T cell function aging
- decrease in number of naive T cells
- increase in number of memory cells
- slower to respond and acquire strong stimulus
aging - extrinsic factors that can lead to infection
- atrophic skin more easily damaged
- decreased cough and gag reflexes make it more difficult to control secretions
- decreased bronchiole elasticity
- denture associated infection
define infection
an organism establishes a parasitic relationship with its host.
pathogen probable outcome 1
Contaminate the body surface and be destroyed by first-line defenses such as intact skin or mucous membranes that prevent further invasion
pathogen probable outcome 2
A sub-clinical infection may occur in which no apparent symptoms are evident other than an identifiable immune response of the host (antibodies levels increase)
pathogen probable outcome 3
A clinically apparent infection in which the host-parasite interaction causes obvious injury and is accompanied by one or more clinical symptoms. This outcome is called infectious disease
infectious disease
A clinically apparent infection in which the host-parasite interaction causes obvious injury and is accompanied by one or more clinical symptoms
incubation period
The period between the pathogen entering the host and the
appearance of clinical symptoms.
- disease symptoms herald the end of the incubation peri
latent infection
Occurs after a microorganism has replicated but remains dormant or inactive in the host, sometimes for years.
period of communicability
host may harbor a pathogen in sufficient quantities to be shed at any time after latency and toward the end of the incubation period.
chain of transmission
- Pathogen or agent
- Reservoir
- Portal of exit
- Mode of transmission
- Portal of entry
- Host Susceptibility
pathogen - chain of infection
The microorganism that has the capacity to cause disease
(arouse a pathologic response) in the host
pathogenicity
The ability of the organism to induce disease, depends on the organism’s speed of reproduction in the host, the extent of damage it causes to tissues, and the strength of any toxin released by the pathogen
Virulence
potency of the pathogen in producing severe disease and is measured by the case fatality rate (i.e., the number of people who die of the disease divided by the number of people who have the disease)
Opportunistic pathogens
They do not cause disease in people with intact host defense systems but can clearly cause devastating disease in people with severe defects in host defense mechanisms (e.g., hospitalized and immunocompromised clients
Resoirvoir
An environment in which an organism can live and multiply
➢Animal, plant, soil, food, or other organic substance or combination of substances.
a carrier maintains an environment that maintains..
growth, multiplication, and shedding of the parasite without exhibiting signs of
disease (e.g., hepatitis)
portal of exit
The place from which the parasite leaves the reservoir
➢Secretions and fluids (respiratory secretions, blood, vaginal secretions,
semen, tears)
➢Excretions (urine and feces)
➢Open lesions
➢Exudates (pus from an open wound or ulcer)
➢HIV has more than one portal of exit
modes of transmission
Contact transmission
➢Direct contact
➢Indirect contact
Inanimate and intermediate objects (fomite)
o Telephone, sphygmomanometer, bedside rails, tray tables, countertops,
and other items that come into direct contact with the infected person.
airborne transmission
Small particles (less than 5 μm) that they are capable of floating on air currents within a room and remain suspended in the air for several hours
➢e.g., tuberculosis, chickenpox, rubeola measles
vehicle transmission
➢Occurs when infectious organisms (e.g., salmonellosis) are transmitted through a common source (e.g., contaminated food, water, and intravenous [IV] fluid) to many potential susceptible hosts.
droplet transmission
Larger particles (greater than 5 μm) than airborne particles.
➢They do not remain suspended in air but fall out within 3 feet of the source travel only a short distance (e.g., influenza) .
Vector-borne transmission
Involves insects and/or animals that act as intermediaries between two or more hosts.
portal of entry
A pathogen may enter a new host by ingestion (GI tract),
inhalation (respiratory tract), or bites or injury of the skin.
- Microbes commonly enter through contact with mucous
membranes and, less frequently, transplacentally.
health-care associated infection
The infections that develop in hospitalized persons or persons
admitted to a health care facility that were not present before
admission.
ex. pneumonia, C diff
HAI causes
The frequent use of invasive devices for monitoring or therapy.
The increased use of immunosuppressants and antibiotics.
More colonization and infection by multidrug-resistant organisms.
Greater debilitation and severity of illness of hospitalized clients
who acquire these infections.
Lack of hand hygiene predispose people to such infections and
superinfections
➢Central line–associated bloodstream infections (CLABSIs)
➢Catheter-associated urinary tract infections (CAUTIs)
➢Ventilator-associated pneumonia (VAP)
➢Surgical site infections (SSIs)
prevention of HAI
***hand hygiene
