what is a communicable disease?
-diseases that can be spread
what did Louis pasteur show in the mid to late 19th century?
that microorganisms cause disease.
-he developed vaccines against diseases such as rabies
the trachea and bronchi as a defence line your body has against the entry of pathogens
- your trachea and bronchi also secrete mucus that traps pathogens from the air.
- cilia move to push the mucus up to the back of your throat where it is swallowed
how are pathogen spread?
- Direct contact
- Air(droplet infection)
- Water
internal defences(the immune system)
-your white blood cells help to defend you against pathogens by ingesting them and by making antibodies and antitoxins
fungal diseases in humans and plants
- there are few fungal diseases that affect people(athletes foot)
- fungal diseases are most common in plants and can be devastating
the skin as a defence line your body has against the entry of pathogens
- your skin covers your body and acts as a barrier
- it produces antimicrobial secretions to destroy pathogenic bacteria
in plants what are the most common pathogens?
viruses and fungi
What is health?
A state of physical and mental well-being
gonorrhoea(bacterial disease)
-sexually tansmitted disease(STD)
symptoms include discharge from the penis and vagina and the pain on urination
-treatment involves antibiotics, although many strains are now resistant
-use of condoms prevents spread
Joseph Lister started use antiseptic chemicals to destroy pathogens before they caused infection in operating theatres
Joseph Lister started use antiseptic chemicals to destroy pathogens before they caused infection in operating theatres
What are communicable diseases caused by?
Microorganisms called pathogens which include bacteria, viruses, fungi, and protests
diseases caused by protists
- they are relatively rare pathogens but the diseases they cause are often serious and damagin to those infected
- isually involve a vector
bacterial disease in plants
- there are relatively few bacterial diseases of plants
- agrobacterium tumefaciens causes crown galls-a mass of unspecialised cells that often grow at the joint between the root and the shoot in infected plants
different types of diseases may and often do interact(one problem can make another worse)
different types of diseases may and often do interact(one problem can make another worse)
the stomach as a defence line your body has against the entry of pathogens
-the stomach produces acid and this destroys the microorganisms in the mucus you swallow and you take in through your mouth
the nose as a defence line your body has against the entry of pathogens
-your nose hairs and mucus trap particles in the air that may contain pathogens or irritate your lungs
hiv/aids(viral disease)
- initially causes flu-like illness
- virus then attacks the body’s immune cells
- body’s immune system becomes so badly damaged it can no longer deal with other infections or cancers
- spread by sexual contact or by the exchange of body fluids(blood)
tobacco mosaic virus(viral disease)
- spread by contact and vectors
- damages leaves and reduces photosynthesis
- no treatment
- spread is prevented by field hygiene and pest control
salmonella food poisoning(bacterial disease)
- spread through food and poor hygiene
- symptoms include fever, abdominal cramps, diarrhoea and vomiting caused by the toxins produced by the bacteria
malaria(protist disease)
- caused by parasitic protists
- spread by the bite of female mosquitoes
- damages blood and liver cells
- causes fevers and shaking, and can be fatal
- some drugs are effective if given early but protists are becoming resistant
- spread is reduced by preventing vectors from breeding and using mosquito nets to prevent people from being bitten
What factors can affect health?
- Diet
- Stress
- Life situations(Gender, ethnic group, where you live)
rose black spot(fungal disease)
- spread in the environment by wind and water
- damages leaves so they drop off, affecting growth so photosynthesis is reduced
- spread is controlled by removing affected leaves and chemical sprays(not very effective)
how can you help prevent the spread of communicable diseases?
- Simple hygiene measures(hand washing, disinfectants on kitchen work surfaces)
- isolation of infected individuals
- destroying or controlling vectors(mosquitoes for malaria)
- vaccination( so immune system is prepared if u become ill)
