Host Microbe Interactions: principles of disease Flashcards
What term is coined for living things living together?
Symbiosis
What flora do not cause disease under normal circumstances?
Normal flora
What flora Colonise for a brief time – does not last, normal flora
competes – may cause disease
Transient flora
What flora causes disease?
Pathogenic flora
What relationship occurs when there is mutual benefit?
Mutualism
What relationship does the Lactobacillus acidophilus and the adult vagina have?
Mutualism
What relationship does Staphylococcus epidermidis and the human skin have?
Commensalism
– Under normal circumstances does not cause harm
What relationship do pathogenic microbes have to its host?
Parasitism
What relationship Occurs when Host becomes predisposed to infection by otherwise harmless microbe? Such as in Candida albicans and the vagina?
Opportunism
What contributes to the manifestation of disease?
Factors of both the microbe, host and environment
Four things a microbe must do to cause disease (to be a pathogen):
• 1. Gain entry to a host – environment
• 2. Attach and multiply – microbial pathogenesis
• 3. Evade Host defences
– host susceptibility / immunity - tomorrow
• 4. Cause damage to tissues – microbial pathogenesis
What is the Period in which microbe attempts to evade host defenses and establish infection
Incubation period
Incubation period of chicken pox
2-3 weeks
Incubation period of pertussis (whopping cough)
7-10days
Incubation period of Covid 19
5-7 days
Summary of incubation periods
Chicken pox 2-3 weeks • Measles 8 – 14 days • Mumps 12 – 25 days •TB 4–12 weeks • Pertussis 7 – 10 days • Food poisoning 12 – 36 hrs • HIV/AIDS 3 weeks - years • Covid-19 5-7 days
What phase of disease is the Period of microbe multiplication
– Mild, non-specific symptoms
– Host defense may overcome infection at this point
Prodromal phase
What phase of disease depicted by Cell damage occurs
– Producing recognisable signs and symptoms
Acute or invasive phase
2 possible outcomes of disease development
Fulminating
Decline and convalescence
What phase of disease development is depicted by when Acute phase develops rapidly, Symptoms appear suddenly, Feature of a very virulent pathogen and has a Fatal outcome
Fulminanting
What phase is described by When host defense overcomes pathogen and Symptoms subside
Decline and convalescence
How does infectious disease become established?
- Gain entry to a host
- Attach and multiply
- Evade Host defences
- Cause damage to tissues
Give 3 reservoir of infection
Humans
Animals
Soil and water
What infection can you get from animals
Zoonoses
What’s the reservoir of infection for melioidosis and legionnaires disease?
Soil and water
5 Modes of transmission of infectious disease
Physical contact Air borne Water borne Food borne Vector
Mode of transmission for sexually transmitted disease
Direct - physical contact
Mode of transmission for flu
Indirect physical contact
Mode of transmission for tuberculosis
Air borne
Mode of transmission for daintree ulcer
Air borne
Mode of transmission for Giardia intestinalis cysts and Cryptosporidium parvuum
Water borne
Mode of transmission for Vibrio spp and Aeromonas spp GIT
WAter borne
Mode of transmission for Toxoplasma gondii – rare kangaroo
Food borne
Mode of transmission salmonella
Food borne
Mode of transmission hepatitis A
Food borne
Mode of transmission malaria
Vector
How do we do infection control
Break transmission cycle
Change host behaviour
Eliminate vectors
What are the portal of entry and exit of pathogens?
Skin Respiratory tract Gastrointestinal tract Urogenital tract Transplacental - mother to baby
5 Infections that have skin as a portal of entry and exit
melioidosis, HIV Hep B needle stick Dermal migrans human hook worm
2 infections using respiratory tract as entry and exit
Streptococcus pnemoniae
Pseudomonas aeruginosa
Portal of entry and exit of Shigella dysenteriae
Gastrointestinal
Give 2 pathogens that use gastrointestinal as entry and exit
Helminthes attach firmly
Protozoa protective cyst
Portal of entry and exit for syphilis and gonorrhoea
Urogenital
Portal of entry and exit for Escherichia coli
Urogenital - UTI
Portal of entry and exit for toxoplasmosis
Transplacental
Give 3 diseases using transplacental route for infections
Rubella
Toxoplasmosis
Cytomegalovirus- CMV