wk 8- infections of public health significance Flashcards
how does the integument (skin) support early trapping, identification and removal of infectious agents? 4
keratinized cells- protective superficial layer
tight junctions- tight epithelial cells in the stratum granulosum maintains barrier integrity.
innate immunity- the dermal layer hosts innate immune cells including natural killer cells
adaptive immunity- the dermal layer hosts adaptive immune cells including T-cells capable of recognition and targeting of intracellular infectious agents
how do mucous membranes support early trapping, identification and removal of infectious agents 4
carina of trachea- specialized epithelial cells at the branching point between the trachea and left and right primary bronchi. these elicit a cough reflex if stimulated
ciliated epithelial cells- coupled with mucus trapping to remove particulate matter and infectious agents via the mucociliary escalator.
goblet cells- the mucous producing cells of the respiratory epithelium contribute to the secretory barrier function of this mucous membrane
innate immune cells- dendritic cells are antigen presenting cells that form part of the immunological barrier of the mucous membrane
how can infectious agents breach the barrier integrity ?
accessory structures - hair follicles, hair, sebaceous glands, sweat glands.
These structures create natural portals of entry to the dermal layer of the cutaneous membrane
wounding- incisions, abrasions or burns can lead to physical disruption to the cutaneous membrane. creates a direct portal of entry for infectious agents of endogenous or exogenous origin.
respiratory system innate defenses9 (defense mechanism and its action)
normal regional microbiota (URT)- competitive inhibition
nasal hairs- trapping of particulate matter
mucus- trapping of foreign material to prevent physical contact with mucus membranes
ciliated epithelium (URT)- movement of mucus and foreign material via the mucociliary escalator
antimicrobial secretions- destruction of infectious agents
secretory immunoglobulin-A (IgA) - neutralization of infectious agents
cough and sneeze reflex- expulsion of particles and secretions from the respiratory tract
alveolar macrophages- phagocytosis of foreign material in the lungs
tonsils and lymph nodes- humoral and cellular immune response
humoral immunity definition
arm of the adaptive immune response active in extracellular fluids
what are the major portals of entry and exit in the respiratory tract? 4
entry:
eyes- cornea (anterior membrane) and conjunctiva (adjacent epithelial border) are portals of entry for respiratory tract.
nasal cavity- normal inhalation through nose, reason for hairs and mucous cells at this site
oral cavity- the endogenous microbiota aids the development of tolerance associated with this process so that we do not mount an over pro-inflammatory response to obtaining nutrients
ears- the external auditory canal is lined by hairs and is the site of production of cerumen (ear wax) produced by sebaceous and apocrine sweat glands. cerumen has antimicrobial properties.
exit: is only oral and nasal cavity
examples of active/passive movement of aerolised moleucles in the respiratory tract
inhalation
exhalation
examples of forceful expelling of aerosolised molecules from respiratory tract
coughing
sneezing
laughing
talking
healthcare programs interrupting each step of the chain of infection !!!!! case studies
infectious agent- prompt identification and diagnosis, effective treatment, decontamination of asymptomatic carriers, surveillance of agents
reservoir- personal hygiene, environmental cleaning to reduce organic material, disinfection and sterilisation
portal of exit- personal hygiene, waste removal/disposal, management of blood and body substances, PPE
mode of transmission- personal hygiene, standard and transmission based precautions, cleaning, disinfection and sterilization, water sanitation and food handling
portal of entry- good personal hygiene, standard and transmission based precautions, cleaning, disinfection and sterilization, aseptic technique, wound care and management of indwelling devices
susceptible host- personal hygiene, diagnosis, treatment and management of co-morbid conditions, cohorting
types of treatment for infections of public health significance? 2
Symptomatic management of an infectious disease is used to reduce patient discomfort and in cases where the infection is self-resolving. Examples of symptomatic management include fluid and electrolyte replacement
Symptomatic management is frequently used for viral infections and gastroenteritis
Antimicrobial therapy is used to support the patient’s immune system to eradicate an infectious agent, and to reduce shedding of the infectious agent to reduce the risk of further transmission.
communicable diseases are?
Infectious diseases that can be transmitted from person to person (communicable or contagious).
knowledge of what things are required to ensure control of an infectious outbreak for public health concern
route of transmission
reservoir
incubation period
treatment
host susceptibility
portal of entry/exit
list common public health infectious concerns
vaccine-preventable diseases
MRO
foodborne infections
bloodborne infections
STI
multiply drug resistant pathogens what are they and what is the issue?
Multiply drug resistant organisms are increasingly common. These infectious agents often acquire resistance genes as a result of selective pressure – that is through exposure of suboptimal levels of antimicrobial agents.
Antimicrobial-resistant organisms create treatment challenges because the choice of available therapeutic agent is reduced, meaning the treating physician has less flexibility in off-setting contraindications or side-effects associated with the patient as a susceptible host.
food borne infections are associated with what and transmitted how?
Foodborne infections are frequently associated with poor sanitation and/or food-handling. Infectious agents associated with foodborne infections are transmitted via the fecal-oral route.
