The Public
Course Introduction
Public Health
• Prevention and management of diseases and other health conditions through
surveillance and the promotion of healthy behaviours, communities and
environments
• Many diseases preventable through single non-medical methods
• Public health communications, vaccination, antibiotic stewardship, needle exchange
system, promotion of safer sex. Examples of public health measures which increase
life expectancy
Epidemiological Transition
1. Age of pestilence and famine- Mortality is high and fluctuating, life expectancy is low
and variable
2. Age of receding pandemics- Mortality progressively declines, with the rate of decline,
life expectancy increases. Population growth is sustained and begins to be exponential
3. Age of degenerative and man-made diseases- Mortality continues to decline and
eventually approaches stability at a relatively low level
Symbiosis
• Any of several living arrangements between numbers of 2 different species, including
mutualism, commensalism and parasitism. Both positive and negative associations are
therefore included, and the members are called symbionts
Pathogenicity
• Ability of a microorganism to multiply and grow within an infected host, at the
expense of the host and without conferring benefits upon the host
• Pathogenic- Capable of causing disease
Commensalism
• Relationship between individuals of 2 species in which one species obtains food or
benefits from the other without harming or benefitting the latter
Epidemiology
• Deals with the incidence, distribution and possible control of diseases and other
factors relating to health.
• Horizontal Transmission- Infected air, food, water, vectors
• Vertical Transmission- Ovum, sperm, placenta, milk contact, vagina
• Incubation period- Building numbers
• Latent period- No symptoms
• Communicability- Infections
,The Public
Types of transmission
• Respiratory or salivary spread- Not readily controllable
• Faecal-oral- Controllable by public health of measures
• Venereal- Difficult to control as social factors are involved
• Vector
• Vertebrate reservoir
• Vector-vertebrate reservoir
,The Public
Introduction to Vaccination
Innate Defences
• Lysozyme in tears and ither secretions dissolves in cell walls
• Normal flora competes with pathogens
• Skin produces antimicrobial fatty acids and its flora inhibit pathogen colonisation
• Rapid pH change between stomach and intestines inhibits microbial growth
• Flushing of UT prevents colonisation
• Removal of particles by rapid passage of air over cilia in nasopharynx
• Mucus, cilia lining trachea suspend and move microorganisms out of the body
• Blood proteins inhibit microbial growth
Innate Immunity (Non-specific immunity)
• The noninducible ability to recognise and destroy an individual pathogen or its
products
• Doesn’t require previous exposure to a pathogen or its products
• Involves recognition of common pathogen-associated molecular patterns (PAMP) on
pathogens
• Mediated by phagocytes
Adaptive Immunity
• Acquired ability to recognise and destroy a particular pathogen or its products
• Dependent on previous exposure to the pathogen or its products
• Directed toward an individual molecular component of the pathogen (antigens)
Antibodies
• Several different classes of antibodies exist and are distinguished from one another
by their amino acid sequence
• Each antibody class has a specific function:
o IgM and IgG found in blood
o IgA found in secretions from mucus membranes
o IgE is involved in parasitic immunity and allergies
, The Public
o IgD is found on surface of B cells
• Provide targets for interaction with proteins of the complement system. Resulting in
destruction of antigens through lysis or opsonisation
• Antibodies can bind to pathogens and toxins and inactivate them
Prevention of infectious disease
• Natural immunity and artificial immunity (vaccination)
B-cells are then stored in lymph nodes after the
person has been immunised so they can be
released rapidly
Artificial Immunity and Immunisation
• Artificial induction of immunity to individual infectious diseases is a major weapon in
the treatment and prevention of diseases
o Artificial active immunity:
▪ Exposure to a controlled dose of harmless antigen to induce formation
of antibodies
o Artificial passive immunity:
▪ Injection of an antiserum derived from an immune individual
o Immunisation:
▪ Process of generating an artificial active immune response by exposure
to an antigen or antigen mixture (vaccine)
• Immunisation with live cells or virus is usually more effective than that with dead or
inactive material
• Most agents used for immunisation are either attenuated or inactivated pathogens
or inactivated forms of microbial products such as toxins
Course Introduction
Public Health
• Prevention and management of diseases and other health conditions through
surveillance and the promotion of healthy behaviours, communities and
environments
• Many diseases preventable through single non-medical methods
• Public health communications, vaccination, antibiotic stewardship, needle exchange
system, promotion of safer sex. Examples of public health measures which increase
life expectancy
Epidemiological Transition
1. Age of pestilence and famine- Mortality is high and fluctuating, life expectancy is low
and variable
2. Age of receding pandemics- Mortality progressively declines, with the rate of decline,
life expectancy increases. Population growth is sustained and begins to be exponential
3. Age of degenerative and man-made diseases- Mortality continues to decline and
eventually approaches stability at a relatively low level
Symbiosis
• Any of several living arrangements between numbers of 2 different species, including
mutualism, commensalism and parasitism. Both positive and negative associations are
therefore included, and the members are called symbionts
Pathogenicity
• Ability of a microorganism to multiply and grow within an infected host, at the
expense of the host and without conferring benefits upon the host
• Pathogenic- Capable of causing disease
Commensalism
• Relationship between individuals of 2 species in which one species obtains food or
benefits from the other without harming or benefitting the latter
Epidemiology
• Deals with the incidence, distribution and possible control of diseases and other
factors relating to health.
• Horizontal Transmission- Infected air, food, water, vectors
• Vertical Transmission- Ovum, sperm, placenta, milk contact, vagina
• Incubation period- Building numbers
• Latent period- No symptoms
• Communicability- Infections
,The Public
Types of transmission
• Respiratory or salivary spread- Not readily controllable
• Faecal-oral- Controllable by public health of measures
• Venereal- Difficult to control as social factors are involved
• Vector
• Vertebrate reservoir
• Vector-vertebrate reservoir
,The Public
Introduction to Vaccination
Innate Defences
• Lysozyme in tears and ither secretions dissolves in cell walls
• Normal flora competes with pathogens
• Skin produces antimicrobial fatty acids and its flora inhibit pathogen colonisation
• Rapid pH change between stomach and intestines inhibits microbial growth
• Flushing of UT prevents colonisation
• Removal of particles by rapid passage of air over cilia in nasopharynx
• Mucus, cilia lining trachea suspend and move microorganisms out of the body
• Blood proteins inhibit microbial growth
Innate Immunity (Non-specific immunity)
• The noninducible ability to recognise and destroy an individual pathogen or its
products
• Doesn’t require previous exposure to a pathogen or its products
• Involves recognition of common pathogen-associated molecular patterns (PAMP) on
pathogens
• Mediated by phagocytes
Adaptive Immunity
• Acquired ability to recognise and destroy a particular pathogen or its products
• Dependent on previous exposure to the pathogen or its products
• Directed toward an individual molecular component of the pathogen (antigens)
Antibodies
• Several different classes of antibodies exist and are distinguished from one another
by their amino acid sequence
• Each antibody class has a specific function:
o IgM and IgG found in blood
o IgA found in secretions from mucus membranes
o IgE is involved in parasitic immunity and allergies
, The Public
o IgD is found on surface of B cells
• Provide targets for interaction with proteins of the complement system. Resulting in
destruction of antigens through lysis or opsonisation
• Antibodies can bind to pathogens and toxins and inactivate them
Prevention of infectious disease
• Natural immunity and artificial immunity (vaccination)
B-cells are then stored in lymph nodes after the
person has been immunised so they can be
released rapidly
Artificial Immunity and Immunisation
• Artificial induction of immunity to individual infectious diseases is a major weapon in
the treatment and prevention of diseases
o Artificial active immunity:
▪ Exposure to a controlled dose of harmless antigen to induce formation
of antibodies
o Artificial passive immunity:
▪ Injection of an antiserum derived from an immune individual
o Immunisation:
▪ Process of generating an artificial active immune response by exposure
to an antigen or antigen mixture (vaccine)
• Immunisation with live cells or virus is usually more effective than that with dead or
inactive material
• Most agents used for immunisation are either attenuated or inactivated pathogens
or inactivated forms of microbial products such as toxins
