communicable diseases & prevention

• What type of pathogen is responsible for Tuberculosis, Bacterial meningitis and Ring rot?

  Bacteria
• What type of pathogen is responsible for HIV/AIDS, Influenza, and Tobacco mosaic virus?

  Virus
• What type of pathogen is responsible for Black Sigatoka, Ringworm, and Athlete‘s foot?

  Fungus
• What type of pathogen is responsible for Potato/tomato late blight and Malaria?

  Protoctist
• How is potato/tomato late blight spread?

  when spores are carried between plants, first in the air then in water

  (indirect transmission)
• How is malaria spread?

  via mosquitoes which are insects that feed on blood

  the mosquitoes act as vectors- they don’t cause malaria themselves, they just spread the protoctista that cause it
• How does overcrowding living conditions increase the transmission of many communicable diseases?

  Close contact increases the spread of pathogens for example, TB is spread directly via droplet infection, it’s also spread indirectly as the bacteria can remain in the air for long periods of time and infect new people, the risk of TB infection is increased when lots of people live crowded together in a small space
• Examples of climate affecting the spread of communicable diseases?

  Potato/tomato late blight is especially common during wet summers as the spores need water to spread.

  Malaria is most common in tropical countries, which are humid and hot. This is because these are ideal condition for mosquitoes to breed.
• Example of social factors increasing the transmission of communicable disease?

  The risk of HIV infection is increased in places where there is limited access to good healthcare as people are less likely to be diagnosed and treated for HIV, and the most effective anti-HIV drugs are less likely to be available, so the virus is more likely to be passed on to others.

  Limited access to education -> less people informed about how HIV is transmitted and how it can be avoided, e.g by using a condom
• Suggest two reasons for the rapid spread of the fungus in the elm population?

  mobile vector

  fungal spores carried by the wind

  overcrowding of trees / small distance between trees
• Identify one similarity in the way malaria is transmitted compared with the way Dutch elm disease is spread?

  vector (ALLOW carried by insects)
• Suggest two ways to minimise the spread of an outbreak of plague?

  stay keep indoors

  increase ventilation

  wear masks

  immediate quarantine for people with symptoms
• How are communicable pathogens transmitted directly?

  1 inhalation (droplet infection)

  2 skin to skin contact

  3 exchange of bodily fluids

  4 penetrate skin actively using enzymes or passively through wounds
• How are communicable pathogens transmitted indirectly?

  1 consumption of contaminated food and drink

  2 via a vector e.g mosquitoes transmit plasmodium parasite

  3 spores
• How do living conditions affect transmission of disease?

  1 overcrowding increases direct transmission

  2 climate determines which organisms can survive e.g malaria is more prevalent in tropical countries, where the vector (mosquitoes) can breed

  3 social factors influence how quickly people are treated, which affects direct transmission (increases or decreases)
• What are ways to minimise the spread of an outbreak of plague?

  stay indoors/ increase ventilation

  wear masks

  strict quarantine for people with symptoms
• why is asepsis important- practical?

  reduces contamination/ microorganisms
• How is the malarial parasite able to bypass the body's primary defences?

  mosquito mouthparts pierce skin

  the pathogen is injected directly into the blood