Health, Safety and you Flashcards
what are types of pathogens
extracellular , bacteria , fungi , parasites , protozoa - examples = streptoccus , pneumoniae , clostridium tentane , tyrapsoma bruchi- disesses oenumonai , teneantus , sleeping sickness
intracellular bacteria , parasites mycobacterium leprae , plasmodium flaicpraum - leporasy malaria
viruses (intracellular) variola , influenza , Hiv
smallpox flu aids
parasitic worms extracellular acaris schistoma , acaris schisomitasis
what is the relative size of medically important micro-organisms
adult tapeworms , some protozoan are visible with the naked eye 2 micrometers
bacteria and mycoplasma and rickesettsia can be seen with a light microscope
chyalimida bacteria , viruses and prions can be seen with an electron microscope
what is entry into the body by injection know as
Entry into the body by injection is known as the parenteral route of inoculation, and distinguishes this route of entry from all other routes e.g. oral or via a wound
what are the different transmission routes of microorgansisms
Soil – worms/some bacteria - eg Ascaris lumbricoides; Cl. tetani
Animals/insects – e.g. rabies virus; Plasmodium spp. (malaria)
Food/water – e.g. Enterobacteria; hepatitis A virus; vCJD
Faecal-oral – e.g. Enterobacteria; hepatitis A; noroviruses
Aerosol – e.g. B. pertussis (whooping cough); measles & influenza viruses
Direct contact – e.g. sexual; e.g. HIV infection; some herpesviruses
Transplacental – e.g. rubella virus; Zika virus?
Iatrogenic – e.g. blood; hepatitis B and C; HIV
how are diseases transmitted via non human sources
dogs infected with rabies virus
Rabies is a vaccine-preventable viral disease which occurs in more than 150 countries and territories
Dogs are the main source of human rabies deaths, contributing up to 99% of all rabies transmissions to humans
Rabies elimination is feasible through vaccination of dogs and prevention of dog bites
Infection causes tens of thousands of deaths every year, mainly in Asia and Africa
40% of people bitten by suspect rabid animals are children under 15 years of age
Immediate, thorough wound washing with soap and water after contact with a suspect rabid animal is crucial and can save lives’
Insects
The female Anopheles mosquito and the malaria protozoan - Plasmodium falciparum
how are miccorganissm transmitted in healthcare settings
Transmission of micro-organisms in a healthcare setting can be:
- through cross-infection (patient to patient), either directly or indirectly
- from patient to healthcare worker
from healthcare worker to patient
PERCUTANEOUS – injuries through needles and other sharps, human bites and human scratches.
MUCOCUTANEOUS – exposures to the mucous membranes of the eyes and mouth.
what are fomites
Fomites are objects or things e.g. a cup or the surface of a table or a bedsheet.
what are nosomial infections
Nosocomial infections are infections occurring in hospitals.
give examples of contaminated sources that may result in transmission of microorganisms between humans
Mucosal secretions and saliva
Fluids from vesicles or other open lesions
Faeces, vomit and urine
Fomites
Pus
Blood
how do respiratory tract infections spread
respiratory tract infections spread via mucosal secretions
what protective procedures in healthcare settings stop the transmission of microoganisms
Preventing micro-organism transmission and spread in the healthcare setting:
. Handwashing and good general hygienic procedures
- Use of appropriate protective clothing
- Appropriate and effective sterilisation of instruments
- Education and awareness
- Immunisation, where available
what bacteria are problem microorganisms in healthcare settings
bacteria
Staphylococcus aureus/MRSA
Pseudomonas aeruginosa
Streptococcus pyogenes
Clostridioides difficile
Klebsiella sp.
Bordetella pertussis
what viruses are problem micoorgansism in healthcare settings
HIV (blood-borne)
Hepatitis B and C (blood-borne)
Herpes simplex virus (HSV) type 1 (from infected lesion fluids)
Noroviruses (from infected faeces or vomit)
Adenoviruses (from infected body fluids)
Ebola viruses (from all infected body fluids)
Coronavirus (respiratory)
what viruses are problem micoorgansism in healthcare settings
HIV (blood-borne)
Hepatitis B and C (blood-borne)
Herpes simplex virus (HSV) type 1 (from infected lesion fluids)
Noroviruses (from infected faeces or vomit)
Adenoviruses (from infected body fluids)
Ebola viruses (from all infected body fluids)
Coronavirus (respiratory)
what is dangerous about mrsa
About 30% of people carriers without symptoms
In healthcare settings, S. aureus infections can be serious or fatal (bacteraemia or sepsis, pneumonia, endocarditis, bone infections)
what is clostridiodes difficile
Causes diarrhoea and colitis
Most infections happen after a course of antibiotics
Symptoms: severe diarrhoea including loose, water stools, frequent bowel movements for several days/fever/stomach tenderness or pain/nausea
what is kelbsiella sp
Gram-negative bacteria
Cause pneumonia, bloodstream infections, wound or surgical site infections, and meningitis
Normally found in the human intestines (not causing disease)/faeces
Patients at risk – on ventilators or catheters/on long course of antibiotics
Healthy individuals are usually not at risk
what is Pseudomonas aeruginosa
Pseudomonas aeruginosa is a gram-negative, rod-shaped bacterium commonly found in soil, water, and vegetation. It is an opportunistic pathogen that can cause infections in humans, particularly in people with weakened immune systems,
Seriousinfections usually to people in the hospital and/or with weakened immune systems
Infections of the blood, pneumonia, and infections following surgery can lead to severe illness and death in these people
Healthy individuals can also develop mild illnesses - ear infections, especially in children and skin rashes after exposure to contaminated swimming pools
Eye infections have occasionally been reported in persons using extended-wear contact lenses
Can be spread on the hands of healthcare workers or by equipment that gets contaminated and is not properly cleaned
what is group a strep
Acute infections may take the form of pharyngitis, scarlet fever (rash), impetigo, cellulitis, or erysipelas
Invasive infections can result in necrotizing fasciitis, myositis and streptococcal toxic shock syndrome
Highly contagious/spreads through airborne droplets when someone with the infection coughs or sneezes, or through shared food or drinks
what is (Bordetella pertussis) – Saliva
Pertussis is a highly contagious disease of the respiratory tract
Many children who contract pertussis have coughing spells that last four to eight weeks
The disease is most dangerous in infants and spreads easily from person to person, mainly through droplets produced by coughing or sneezing.
The first symptoms generally appear 7–10 days after infection, and include mild fever, runny nose, and cough, which in typical cases gradually develops into a paroxysmal cough followed by whooping (hence the common name of whooping cough).
In the youngest infants, the paroxysms may be followed by periods of apnoea.
Pneumonia is a relatively common complication; seizures and encephalopathy occur more rarely. Untreated patients may be contagious for three weeks or more following onset of the cough. Pertussis can be prevented by immunization.
how is hiv 1 spread
Spread from contaminated needles, blood or blood-products, the main problem for hospitals
Virus has been isolated from human blood, semen, vaginal secretions, saliva, tears and breast milk. Commonest routes of transmission are via blood, semen and vaginal secretions
Contact with saliva is not a route of infection, and there is no evidence for transmission by an airborne route or via food, water, fomites or insects
Skin or mucous membranes must be broken for HIV-1 to infect
what are the risks for the transmission of hiv 1
Blood transfusions and Factor VIII – 3-5% of all infections
Rate of transmission from infected blood by transfusion – 90%
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Intravenous drug abuse – 5-10% of all infections
Rate of transmission from needle stick – 0.5% per episode
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Sexual intercourse – 80% of all infections
Rate of transmission following vaginal intercourse – 0.1% per episode
Rate of transmission following anal intercourse – 1.0% per episode
(Risk of transmission is higher to the passive {receptive} partner)
(Concurrent STD enhances the above risks by 10-fold)
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Perinatal infection – 10% of all infections
Rate of transmission from mother to infant – 12% - 40%
(via transplacental, intrapartum, blood, genital secretions, breast milk)
what virus causes aids
hiv
hiv enters host cell
viral rna
rna dna hybrid
viral proteins
what are the stages of hiv 1 replication
Attachment to host cell receptor
Viral core with ssRNA and reverse transcriptase (RT) enzyme released into the host cell cytoplasm
RT enzyme converts viral ssRNA into viral dsDNA
Viral dsDNA enters host cell nucleus and is incorporated into the host cell genome through activity of viral integrase enzyme
Integrated viral dsDNA (termed ‘provirus’) remains latent in host cell genome until cell is activated by a foreign protein
