HLTH111

• Communicable disease


  An illness caused by a specific infectious agent (such as bacteria, viruses, parasites or fungi) or its toxic product that results from transmission of that agent or its products from an infected person, animal, or reservoir to a susceptible host, either directly or indirectly through an intermediate plant or animal host, vector or inanimate environment
• Non-communicable disease


  A medical diagnosis involving a long course in the development of symptoms with a progressively deteriorating path
• Epidemiological triangle


  • Two models to describe communicable disease
• Top five outbreaks in history


  • Plague: Europe (14th century)
  • Spanish Flu (1918)
  • HIV/AIDS (1981 – present)
  • Plague: Egypt – Rome (541)
  • Smallpox: Iraq – Rome (165-180)

  
• Smallpox killed 300 million people worldwide in the 20th century but has since been eradicated from the human population
• Modes of transmission of communicable disease


  • Contact transmission
  • Vehicle transmission
  • Vector transmission
• Types of contact transmission


  • Direct contact
  • Indirect contact
  • Droplet transmission
• Examples of contact transmission


  • Physical contact such as handshaking, kissing, sexual intercourse
  • Drinking glasses, toothbrushes, toys, punctures
  • Sneezing
• Examples of agents transmitted by contact


  • Genital warts, herpes, rabies, chlamydia, HIV, head lice, MRSA, chickenpox
  • Measles, hepatitis B and C
  • Whooping cough, strep throat, TB, influenza
• Types of vehicle transmission

  • Airborne
  • Waterborne
  • Foodborne
• Examples of vehicle transmission


  • Dust, droplet
  • Swimming Pools
  • Poultry, Seafood, Meat
• Examples of agents transmitted by vehicle


  • Influenza, measles
  • Cholera
  • Hepatitis A
• Types of vector transmission


  • Mechanical
  • Biological
• Examples of vector transmission


  • Flies, cockroaches
  • Lice, mites, mosquitoes
• Examples of agents transmitted by vector


  • E. coli diarrhoea, salmonellosis, cholera
  • Malaria, yellow fever, Lyme disease
• Cholera is a communicable disease
• Sporadic disease


  Occurs occasionally and at irregular intervals
• Endemic disease


  Exists permanently in a particular region or population
• Epidemic


  Sudden increase in frequency above expected number, affects many people at the some time, spread through one or several communities
• Pandemic


  Increase in disease occurrence within large population over wide region (usually worldwide)
• Tuberculosis, Malaria, HIV/AIDS, Diarrhoeal disease, Measles, Cholera, Influenza, and Polio are communicable diseases
• Strategies to control communicable diseases


  • Removing the agents
  • Controlling the reservoir
  • Physically preventing transmission from the reservoir
  • Isolating or quarantining the infected host
  • Preventing infection in a new host
• Communicable disease prevention methods


  • Societal/environmental structures
  • Vaccination
  • Vector control
  • Personal protection
• Vaccination


  To make large proportions of populations actively immune to bacterial or viral diseases such that that host is able to generate an active antibody immune response to combat an infectious agent
• Vaccine


  A suspension of live or killed micro-organisms or antigenic portion of those agents presented to a potential host to induce immunity to prevent the specific disease cause by that organism
• Emerging and re-emerging infectious diseases occur randomly when risk factors align, are often associated with contact at the animal/human interface, spread internationally by humans/animals/insects/food, have a negative impact on economies, put health workers at great risk, and involve complex relationships across sectors
• Communicable disease


  An illness caused by a specific infectious agent (such as bacteria, viruses, parasites or fungi) or its toxic product that results from transmission of that agent or its products from an infected person, animal, or reservoir to a susceptible host, either directly or indirectly through an intermediate plant or animal host, vector or inanimate environment
• Non-communicable disease


  A medical diagnosis involving a long course in the development of symptoms with a progressively deteriorating path
• Two models to describe communicable disease


  • Epidemiological triangle
  • Chain of infection
• Top five outbreaks in history


  • Plague: Europe (14th century)
  • Spanish Flu (1918)
  • HIV/AIDS (1981 – present)
  • Plague: Egypt – Rome (541)
  • Smallpox: Iraq – Rome (165-180)
• What disease killed 300 million people worldwide in the 20th century but has since been eradicated from the human population?
• Modes of transmission of communicable disease


  • Contact transmission
  • Vehicle transmission
  • Vector transmission
• Types of contact transmission


  • Direct contact
  • Indirect contact
  • Droplet transmission
• Examples of contact transmission


  • Physical contact such as handshaking, kissing, sexual intercourse
  • Drinking glasses, toothbrushes, toys, punctures
  • Droplets from sneezing
• Examples of agents transmitted by contact transmission


  • Genital warts, herpes, rabies, chlamydia, HIV, head lice, MRSA, chickenpox
  • Measles, hepatitis B and C
  • Whooping cough, strep throat, TB, influenza
• Types of vehicle transmission

  • Airborne
  • Waterborne
  • Foodborne
• Examples of vehicle transmission


  • Dust, droplet
  • Swimming Pools
  • Poultry, Seafood, Meat
• Examples of agents transmitted by vehicle transmission


  • Influenza, measles
  • Cholera
  • Hepatitis A
• Types of vector transmission


  • Mechanical
  • Biological
• Examples of vector transmission

  • Flies, cockroaches
  • Lice, mites, mosquitoes