infective organs Flashcards

1
Q

what is a pathogen?

A

its anything that causes diseases

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2
Q

what does a pathogen cause?

A

cliniical symptoms
it also causes pathogenic effects
- these can vary with organism
- it can affect different parts of the body- may not be related to the site of entry of the pathogen
- can vary in severity
- can be restricted to certian populations due to their genetic material
- can be accute or chronic
- study of different organisms to understand them- useful for food, medical reasons and commercial interest

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3
Q

what are the characteristics of a virus?

A
  • theyre small

- theyre made up of genetic material

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4
Q

what is the structure of a virus?

A

core- 1 or 2 molecules of DNA/ RNA
capsid- RNA/DNA enclosed in a protein coat
envelope- some have an outer layer which can have lipids, carbohydrates and proteins in it
virion- a virus particle, 10-400nm

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5
Q

what is the life cycle of a virus?

A
  • an extracellular virion enters the host cell and begins its ‘intracellular phase’
  • specific cell target ‘virus factory’ relases virions
  • retroviruses make host cells create their DNA from RNA viral template
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6
Q

what does the host have to control to stop a virus infecting itself?

A
  • the virus particles (virions)
  • the virus infected cells
  • viral toxins
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7
Q

what is measles?

A

its a viral infection caused by the measles virus
the virus is an envloped single-stranded RNA virus of the genus morbillivirus
its also very contagous and responsible for 6 million deaths in the 1960s

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8
Q

what is coronavirus?

A

its a viral infection caused by (SARS)-CoV-2

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9
Q

what is the structure of (SARS)-CoV-2?

A

it has positive-sense single-stranded RNA virus
it also has an envelope and glycoproteins on its surface
e.g. spike protein is 50-200nm

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10
Q

what is transmission of (SARS)-CoV-2 caused by?

A
  • its mainly caused by respiritory droplets, direct human contact and fecal-oral route may also occur
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11
Q

what does (SARS)-CoV-2 affect?

A
  • it affects the respiritory tract, initial symptoms of common cold, fever, dry cough, nasal congestion, sore throat, diarrhoea, severe pneumonia, difficulty breathing and can be fatal
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12
Q

what are bacteria?

A

theyre microspopic organisms that can be free-living or parasitic

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13
Q

what are the three main shapes of bacteria?

A
  • rod
  • spherical
  • spiral
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14
Q

what is more complex: viruses or bacteria?

A

bacteria

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15
Q

what are some of the structures bacteria have?

A
  • cell wall
  • a capsule around the cell wall
  • outside structures i.e flagellum and/or pilli
  • BUT the structure depends on the species
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16
Q

what is salmonella?

A

its a bacteria which is gram-negative and intracellular

theres over 2500 types (serovars)

17
Q

how is salmonella transmitted?

A

by faecal-oral route and 94% of cases are from contaminated food

18
Q

what are the symptoms of salmonella?

A

diarreal disease

19
Q

what is TB and how is it transmitted?

A

its a bacterial pathogen which initially infects the lungs by droplet infection then spreads to other parts of the body
its an intra-macrophage pathogen

20
Q

why is TB such a concern?

A

as its multi-drug resistant (MDR TB) and is a significant threat to global health

21
Q

is there a vaccine against TB?

A

yes, theres the BCG vaccine which people are vaccinated with a weakened strength of TB bacteria

22
Q

what are the symptoms of TB?

A
  • fever, night sweats and weight loss
23
Q

what are fungi?

A

theyre larger pathogens which you can see with the naked eye but their spores are microscopic
the spores germinate to produce a pycelium- hyphae grow out in the medium used for growth

24
Q

how are fungi spores dispersed?

A

by the wind or animals

25
Q

what is candidiasis and who is at risk of it and what are the symptoms of it?

A

its an infection caused by the fungus Candida Albicans
its an opportunistic infection which occurs because the patient is immunosuppressed
its a part of the normal flora found on mucosal surfaces like mouth and genitals
patients with HIV, cancer, diabetes and transplants are at risk
- the clinician symptoms depend on the site of infection

26
Q

what are the different forms candidiasis can take?

A
  • oropharyngeal
  • oesophageal
  • systemic
  • nappy rash
27
Q

what must the immune response control in candidiasis?

A
  • budding yeast cells
    psudo hyphae
  • hyphae
28
Q

what must the immune response control in candidiasis?

A
  • budding yeast cells
  • psudo hyphae
  • hyphae
29
Q

what is systemic candidiasis?

A

its a fungal infection with 30-50% mortality when left untreated
in 10% of cases, it causes macronodular skin lesions
10-28% of cases have candidal endophthalmitis (inflammation in the eye)
septic shock (hypotension, tachichardia, tachpynea) may also occur
disseminated candidiasis - 40-60% blood cultures may be negative

30
Q

what are parasitic infections?

A

its an infection caused when the immune system cant control the parasite
theyre multi/unicellular infections which can be intra/extracellular
they occur in different locations

31
Q

what examples of parasitic infections?

A

malaria - trophozites 1-2 microns

helminths- tape worm 15m long

32
Q

how do intracellular parasite and intracellular parasite?

A

intracellular- kill

33
Q

how are intracellular parasites and intracellular parasites killed?
[what examples do you know?]

A

intracellular- killed by activating the infected cell [leishmania parasite inside macrophages] or by eliminating the infected cell [use cytotoxic T lymphocyte e.g. toxoplasma]

extracellular - too big for cells to kill the whole organism so need to damage the parasite[ gut parasite- expelled by the accumulation of fluid in the gut and production of diarrhoea, tissue parasite- damage and break down]
both ways require co-operation between a range of immune cells and other mechanisms]

34
Q

what are gastrointestinal nematodes?

can you name any different types?

A

theyre also known as round worms, and are a parasite

there are many different types: ascaris, tichuis, hook worms: nector and anacylostoma, enterobius, toxocara

35
Q

what are the symptoms caused by round worms?

A
  • diarrhoea
  • blood in faeces
  • passing the worm in faeces
  • mild > severe stomach pain
  • nausea
  • vomiting
  • weight loss
36
Q

what is the life cycle of ascaris?

A
  • the host is infected by 2nd stage larva in eggs
  • the eggs hatch in the gut
  • the larva migrate though the tissues into the lungs
  • it passes up the trachea and is then swallowed
37
Q

what do hook worms cause?

A

theyre a parasite that infect 576-740 million people
they cause physical and intellectual development changes in children
- they affect the economic development of communities