Host Microbe Interaction Flashcards
Clinical Infection
Infections with signs and symptoms
Sub-clinical Infection
Infection with pathogen but no symptoms
Iatrogenic Infection
From a medical practitioner / intervention (hospital)
How are respiratory infections transmitted?
- Droplets (cough-sneeze)
- Saliva
- Soil-dust
- water aerosols
Zoonoses is a term used for what kind of disease?
Diseases transmitted by vectors (insects and animals)
Endemic
Disease present in a community (region) all the time,
usually only clinical in a few
Epidemic
Wide spread disease within a community (region),
affecting many people but only occasionally present
Pandemic
Wide spread epidemic, not confined to a single
community or region (more than one continent)
Sporadic
Widely scattered disease, occurring singly,
irregularly, infrequently
Epidemiology
The study of the spread, frequency, distribution of
disease
Explain the difference between Morbidity and Mortality
Mortality: Number of deaths caused by infective agent
Morbidity: Number made ill by infective agent
Explain the difference between Incidence and Prevalence
Incidence: Number of new cases over specific period
Prevalence: Number of cases (infected or diseased) at a given time (old and new cases)
In epidemiological terms how would you classify the disease “AIDS”
AIDS is a pandemic; wide spread epidemic
What factors influence the spread of disease in a community?
- Virulence of the pathogen
- Pathogen transmission mode
- Population susceptibility and immunity
List four ways of preventing the spread of disease in a community
- Immunisation
- Prevent contamination of water supplies
- Isolate diseased persons
- Educate the public
Which disease of the following disease type would most likely spread quickly through the Perth community and why? Gastroenteritis, STI, Respiratory disease
STI; HPV 53 was the most prevalent in a WA study, can be spread quickly and easily
What are the two branches of the immune system?
Innate: Non specific defences which do not require
previous exposure to foreign agent
Adaptive: Response based on specific recognition of invader (foreign agent), consists of antibody mediated and cell mediated responses
How does skin protect against bacteria?
- Contains normal flora to provide competition for pathogenic microbes that want to grow on the skin
What white blood cells (WBC) types are phagocytic?
Neutrophils, monocytes and eosinophils
What type of white blood cell (WBC) is mainly involved in the adaptive immune system?
Lymphocyte
What antibody types are involved in the primary and secondary immune response?
Primary: IgM
Secondary: IgG
What type of lymphocyte is involved in cell mediated immunity?
T-lymphocyte
List the ways antibodies fight infection.
- Neutralise viruses and toxins
- Trigger phagocytosis
- Aggultination
List the antibody isotypes
- IgG
- IgA
- IgM
- IgE
- IgD
What are the 4 cardinal signs of inflammation and how do they come about?
- Redness (increased blood flow)
- Heat (increased blood flow)
- Swelling (lymphatic fluid)
- Pain (inflammatory substances released cause pain)
Describe the difference between humoral and cell mediated immune responses.
Humoral: uses antibodies as main form of immune response
Cell-mediated: uses cytotoxic T-cells and natural killer cells as main form of immune response
List and describe the types of T cells
- Cytotoxic T cells
- Natural killer cells
What is the MHC and what is its purpose?
- Major Histocompatibility Complex
- purpose is to bind peptide fragments from pathogens and display them on the cell surface in order to recognised by the appropriate T–cell for destruction
Describe the difference between passive and active vaccination
Passive:
- Rely on injected antibodies into the body against a particular antigen
- Often happens after an infection
- The recipient does not produce an immune response of their own
- Short term
Active:
- Rely on administering an antigen into the body so the body can produce its own antibodies
- Prophylaxis (prevents future infection)
- Recipient produces their own immune response and remembers antigen for secondary responses
- Long term
How do autoimmune diseases occur?
- When the immune system attacks itself
- Example is type 1 diabetes mellitus
- Destruction of the β-cells of islets of langerhans in pancreas
- β-cells responsible for insulin production
- Cytotoxic T cells followed by auto-antibodies
- Anti-Islet cell antibodies (ICA)
