Objective 1 and 2 Flashcards
define epidemiology
the study of the factors and mechanisms that influence the frequency and distribution of disease
what is the importance of epidemiology? (4)
- Identify - the cause and risk factors
- Measure - the impact on the community
- develop and evaluate - interventions
- inform - public policy (prevention and health promotion)
What are the 4 methods of transmission of pathogenic micro-organisms?
- Contact infection
- Air-borne
- water and food borne
- trauma mediated
what are the 3 types of contact infection (direct person to person)?
- congenital
- sexual
- other
what is congenital infection?
being born with the infection
what are 3 ways congenital infection can occur?
- transmitted across the placenta
- acquired from mother during birth
- passed from mother to child, directly from one generation to the next
what are 3 examples of viral congenital infection?
- rubella
- HIV
- cytomegalovirus
what is an example of a bacterial congenital infection>
treponema pallidum - syphilis
neisseria gonorrhoeae - acquired during delivery
what is an example of a protozoa congenital infection?
Toxoplasma gondii - toxoplasmosis
how does sexual contact infection occur?
organisms are transferred from one person to another bu direct mucous membrane contact or in shared body fluids
what are 7 examples of STI’s?
- herpes
- gonorrhoea
- syphilis
- HIV
- hepatitis B
- trichomoniasis
- chlamydia
what are the 3 other forms of contact infection?
- non sexual direct contact
- auto-infection
- fomites
what are examples of non-sexual direct contact?
handshaking
hugging
important in nursing when carrying organisms from one pt to another
what is auto-infection?
infection due to contact with oneself
what are 3 examples of auto-infection?
- e.coli from large intestine causing UTI
- inunction where surface organisms are driven deeper into the skin due to pressure or friction
- staphylococcal infections of hair follicles (boils)
What are fomites?
infections acquired through contact with inanimate objects contaminated by another person
what are 3 examples of fomites?
- athletes foot
- cold sores (contracted from sharing cups etc)
- inadequately cleaned or sterilized instruments or appliances
How are airborne infections spread?
transmitted by the deposition of pathogens on the mucous membranes of the nose, pharynx, trachea and bronchial tree during inhalation
what are 3 examples of bacterial air borne infections?
- diphtheria (Corynebacterium diphtheriae)
- tuberculosis (Mycobacterium tuberculosis)
- whooping cough (Bordetella pertussis)
what are 3 examples of viral airborne infections?
- measles
- influenza
- common cold
what are airborne droplets?
- the aerosol from coughing or sneezing
- droplets are mainly saliva from front of mouth
- contain very few pathogens
- not mian vehicle of transmission
what are air-borne dried particles?
- derived from nasal mucus or sputum (actual site of infection)
- pathogens are alive in dried deposits and protected by dry mucus
- small size so can remain suspended in air currents for a long times making them more infectious over distance
what are 4 examples of water and food borne infections?
- Dysentery (Shigella dysenteriae)
- Cholera (Vibrio cholerae)
- Typhoid (Salmonella typhi)
- Poliomyelitis (virus)
what are prevention methods for water and food borne infections?
- Proper water treatment (filtration, chlorination, routine monitoring)
- correct sewage treatment and disposal
- Proper food hygiene in food production processing and preparation
what are trauma mediated infections?
- occurs when integrity of body surface (i.e. skiin barrier) is lost
- can occur by implantation or injection
what is implantation trauma?
accidental trauma or deliberate surgical procedures that expose underlying tissue to potential pathogens
what are examples of infections caused by implantation trauma?
- haemolytic streptococci
- staphylococcus aureus
- pseudomonas aeruginosa
- clostridium perfringes and clostridium teatani (spore forming)
what is injection trauma?
penetration of the skin and the introduction fo micro-organisms to tissues wiuthout disruption to outer layers of body
what are the 2 categories of injection?
- natural
- artificial
what is natural injection?
occurs as part of the normal disease transmission process adopted by micro-organisms that use blood-sucking insects as vectors of the disease
what are examples of natural injection infection?
malaria (Plasmodium spp), bubonic plague (Yersinia pestis), Dengue fever, yellow fever
- Animal bites that puncture rather than rip
what is artificial injection?
transmission of disease from one perosn to another via needles, syringes, blood or blood clots
what are 3 examples of artificial injection infections>
- hep B and C
- HIV
- malaria
