topic 5 causes of disease Flashcards
health
state of mental, physical and social wellbeing
disease
disorder of the body that negatively affects an individual’s health
communicable disease
person to person
pathogen
disease causing organism
symptom
change experienced by an organism that indicates disease
why does having an illness make an individual more likely to contract another disease?
-weaken an individual’s immune system making them increasingly susceptible to other infections.
describe cholera
-Caused by Vibrio cholerae bacterium
-Spread by drinking water or washing in water that has
been contaminated with infectious faeces
-Symptoms: diarrhoea, vomiting
How can the incidents of cholera be reduced?
- access to clean water
- improved sanitation (sewage disposal etc.)
describe TB
- Mycobacterium tuberculosis bacterium
- airborne bacteria spread by droplet infection
- Symptoms: lung damage, chesty cough, wheezing
how can the transmission of TB be reduced?
- improved hygiene (washing hands, sneezing into tissues etc.)
- infected individuals should avoid crowded areas
- increased ventilation in the individual’s home
describe Chalara ash dieback
- caused by a fungus that infects ash trees
- airborne spores which are carried by the wind
- causes dark lesions on bark and blackened leaves which wilt and eventually die
how can the transmission of chalara ash dieback disease be reduced?
- control the movement of ash trees
- kill infected plants
- replant with a different species
describe malaria
- spread by mosquito vectors which pick up the plasmodium protist when feeding on the blood of an infected organism and transmit malaria to other organisms during feeding
- flu-like symptoms, damage to red blood cells, liver damage
how can the incidence of malaria be reduced?
- mosquito nets
- insect repellant
- cover arms and legs
describe stomach ulcers
- transmitted orally by eating infected foods or drinking infected water
- symptoms: stomach pain, vomiting, nausea
how can the transmission of helicobacter pylori be reduced?
- access to clean water
- improved hygiene
- improved sanitation (sewage disposal etc.
describe ebola
- caused by Ebola virus
- spread by direct contact with infected body fluids e.g. blood, semen, saliva, mucus, vomit
- symptoms: fever, diarrhoea, vomiting, internal bleeding
how can the transmission of ebola be reduced?
- improved hygiene
- isolating infected individuals
- sterilisation of outbreak areas
describe simply how viruses cause disease
- enter host cells and replicate inside of them
- the host cells rupture, releasing new viruses.
how do viruses differ from other microorganisms e.g. bacteria, fungi?
- viruses are not living organisms
- do not reproduce
- can only replicate inside a host cell
by what two pathways do viruses replicate inside living cells?
- lytic pathway
- lysogenic pathway
describe the lytic pathway
- Virus binds to specific receptors on host cell
- Virus injects its DNA into host cell and replicates its DNA using host cell machinery
- New viral structures are produced and assembled
- Host cell ruptures, releasing new viruses
describe the lysogenic pathway
- Virus binds to specific receptors on host cell
- Viral DNA injected into host cell and becomes integrated into host cell genome
- Viral DNA replicates each time the host cell divides. However, the cell remains normal.
- Trigger causes the activation of viral DNA. It enters lytic pathway.
describe HIV
- caused by human immunodeficiency virus
- spread by direct contact with infected body fluids
- destroys white blood cells making the individual immunodeficient and increasingly susceptible to other diseases.
- leads to AIDS.
