BIO M7

• Disease: any process or condition that adversely affects the normal functioning of a living thing or parts of a living thing.
• Infectious diseases: caused by (caught from) another organism or infective agent called a pathogen.
• Non-infectious diseases: caused by genetics, environmental influences or cellular malfunction.
• Pathogen: a biological agent that causes disease or illness in a host organism.
• Examples of infectious diseases

  A) bacteria

  B) fungi

  C) macroparasite

  D) protozoan

  E) virus

  F) prion

  G) soft rot

  H) tuberculosis

  I) rust

  J) tinea (athlete's foot)

  K) round worm

  L) round worm

  M) wilt disease

  N) malaria

  O) tobacco mosaic virus

  P) aids

  Q) kuru

  
• Broad classification of pathogens

  A) pathogens

  B) microscopic organisms

  C) macroscopic organisms

  D) non-cellular

  E) cellular

  F) live outside body

  G) live inside body

  H) proteins

  I) protein coat

  J) prokaryote

  K) eukaryote

  L) prions

  M) viruses

  N) bacteria

  O) fungi

  P) protozoans

  Q) ectoparasites

  R) endoparasites

  
• Cellular and Non-cellular Pathogens

  A) cellular

  B) non-cellular

  C) living

  D) non-living

  E) protozoans

  F) fungi

  G) prokaryote

  H) virus

  I) prion

  
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  A) bacteria

  
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  A) fungi

  
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  A) protozoa

  
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  A) virus

  
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  A) Helminths

  
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  A) anthropods

  
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  A) prions

  
• Transmission: the way a pathogen spreads disease from one host to the next.
• Chain of infection

  1. A host that is susceptible to the disease
  2. A pathogen that is capable of causing the disease
  3. A mode of transmission
• Mode of transmission: a way for the pathogen to get from host to host
• Modes of transmission

  A) direct contact

  B) indirect contact

  C) vector transmission

  D) direct

  E) blood

  F) bodily fluids

  G) direct

  H) wounds

  I) hiv/aids

  J) pathogen

  K) host

  L) non-living object

  M) host

  N) influenza

  O) pathogen

  P) organism

  Q) malaria

  
• Epidemics

  When conditions are favourable to the pathogen and its transmission, an epidemic may occur. Any epidemic is an increase in the occurence of a particular disease within the population of a defined area.
• Pandemic: disease spreads to many countries throughout the world.
• Endemic: disease is always present in a particular part of the world.
• Sporadic: disease is present in different places at different times, with no known connection between the outbreaks, i.e. occur at different of irregular intervals.
• Cholera is a diarrheal illness caused by infection of the intestine with the toxigenic bacterium vibrio cholera.

  The cholera bacterium is usually found in water or food sources that have been contaminated by faeces from a person infected with cholera. Found and spread in places with inadequate water treatment, poor sanitation, and inadequate hygiene.
• Epidemic: disease is found in a defined area.
• Adaptations to facilitate adhesion to and invasion of host by pathogens

  In order to colonise an animal, pathogens must overcome many host barriers or defence mechanisms.
• Vectors

  An important adaptation for many animal pathogens is the use of vectors to overcome the skin barrier. the outer layer of skin is impenetrable to most microorganisms unless the skin is broken. pathogens that use biting insects as vectors can penetrate the skin barrier.
• antigenic variation

  some pathogens are able to change their antigens (molecules that can induce the immune response) so that the host does not recognise it upon secondary exposure. antigenic variation gives the pathogen more time to colonise the host.
• Some pathogens have adaptations that let them survive the white blood cells sent to destroy them.
• some bacteria can connect to each other in a sticky extracellular matrix to form a biofilm. biofilms enable the bacteria to increase tolerance to antibiotics and immune resonses, giving more protection.
• spontaeous mutations can occur in bacteria dna, making the bacteria antibiotic resistant. biofilm growth also promotes the transfer of antibiotic resistance between bacterial cells in a process known as horizontal gene transfer. plasmids carrying drug resistance can be transferred between bacteria in this way.

  A) antiobiotic resistant bacterium

  B) antibiotic sensitive bacterium

  C) chromosome

  D) plasmid carrying resistance genes

  E) conjugation

  F) plasmid copy is transferred

  G) both bacteria are antibiotic resistant

  
• Some pathogens have adaptations that cause symptoms within the host to aid in the spread of the disease. Other pathogens can modify the behaviour of the host to assist pathogen transmission.
• Host symptoms (e.g. diarrhoea, coughing and sneezing) help transmit pathogens by contaminating water and food, intermediate surfaces or through direct contact.
• change in host behaviour example

  Toxoplasma gondii causes toxoplasmosis in many mammals, reduces infected rodents fear of cats, making it more likely to be preyed upon by cats, who are the host of the protozoan.
• transmission adaptations of pathogens

  A) prion

  B) virus

  C) bacteria

  D) protozoa

  E) fungi

  F) macroparasite

  G) tumuor necrosis factor

  H) dendritic

  I) lymphoid

  J) proteins

  K) host

  L) enters

  M) endocytosis

  N) pili

  O) fimbria

  P) bacteria

  Q) pili

  R) epithelial cell

  S) microtubules

  T) protozoan

  U) host

  V) fungi

  W) molecules

  X) immunodulatory proteins

  Y) immune

  
• koch's postulates experiment

  A) healthy organism

  B) red blood cell

  C) causative agent absent

  D) diseased organism

  E) suspected agent

  F) causative agent present

  G) injection with cultured agent

  H) causative agent present

  
• koch's postulates

  A) causative agent

  B) absent

  C) healthy

  D) present

  E) diseased

  F) isolated

  G) diseased

  H) grown

  I) pure

  J) culture

  K) cultured agent

  L) same

  M) inoculated

  N) healthy, susceptible

  O) causative

  P) reisolated

  Q) inoculated, diseased

  
• Koch (the father of bacteriology) identified the specific type of bacteria that caused several diseases. Showed experimentally that transferring specific bacteria into a healthy animal caused this animal to develop the disease. In doing this work, koch developed conditions that can be used to determine the specific pathogen that causes a disease known as Koch's postulates.
• Robert Koch developed new equipment and techniques that allowed bacteria to be studied (still used today) in studying the cause and transmission of a disease.
• Disease in agriculture can result in reduced production and shortages driving up prices for customers. Biosecurity is very important to prevent the spread of disease.
• Agriculture is a form of primary industry that involves the cultivation of crops and pastures and the rearing of animals to provide meat, milk, fibres and other products for humans.

  Stringent biosecurity measures are in place to reduce the likelihood of disease transmission from pathogens.