6.2 non-bacterial pathogens


Viruses as pathogens

-viral infections are often specific to specific tissues

-each type of virus can only bind to specific antigens on host cells as they only have the specific receptors


  • is a respiratory infection
  • its modes of infection are thorugh droplet infection, contact with contaminated animal droppings and touching surfaces that have been contaminated with the virus
  • it can be a zoonotic infection ie can cross species barriers from animals to humans
  • it infects ciliated epithelial cells of the respiratory system
  • the viral RNA reproduces in the host cells then kills the cell by lsysis, releasing new viruses
  • the death of the epithelial cells leaves the airway open to infection
  • most deaths form flu are form secondary bacterial infections
  • the very young, the very old and those with prior health conditions are the most susceptible to the flu
  • ech eyar, the flu virus chanegs slightly, meaning it is difficutl to mke a vaccine against it as the markers on the cell surface change
  • pathogenic effects include fever, shivering, sweating, painful joints, nausea, headaches, sore throats, feelign unwell etc
  • normally clears after 5-7 days although peopel can feel ill up to 12 weeks afters
  • there is no cure
  • it is an rna virus so is prone to mutation

Fungi as pathogens

-have chitin cell walls

-grow long hyphae

-reproduce through spores

-Stem rust fungus=

  • it is a parasitic fungus and feed off the tissue of the living host
  • the disease is transmitted with spores from infected plants are blown by the wind and carried to new plants or from infected soil left after harvest
  • the spores land on the stem, hyphae penetrate the stomata of the plant cell once the spore has germinated
  • the…


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