B5 - Communicable Diseases Flashcards
Communicable disease
Caused by pathogens such as bacteria and viruses
that can be passed from person to person
Bacteria
Single-celled living organisms
Split in two and produces toxins
Reproduce rapidly
Virus
Very, very small and have a regular shape
Take over the cells of your body to reproduce, causing damage and destroying cells
Reproduce rapidly
Natural barriers to pathogens
Chemical in tears
HCl acid in stomach
The skin on our body
White blood cells
Ingest pathogens (phagocytosis)
Produce antibodies
Produce antitoxins
Preventing spread of pathogens
Isolate those infected
Destroying vectors that carry the disease
Vaccinations
Herd immunity
When enough people are immune to a disease so the infection can’t spread from one person to another
Process of malaria
An infected mosquito bites a human
The mosquitos salivary glands enter the humans blood stream
Via the bloodstream malarial parasites enter liver cells and reproduce asexually
The parasite cells produced in the liver can enter the red blood cells causing them to rupture, starting the symptoms of malaria
Some parasites develop into male and female reproductive cells
The red blood cells with both male and female reproductive cells are transferred to another mosquito when it feeds on the infected human
Preventions of malaria
Travellers take anti-malarial drugs
Mosquito nets around beds when sleeping
Remove stagnant water and spray water with insecticides
Tobacco mosaic virus
‘Mosaic’ pattern of discolouration on the leaves
Rose black spot
Purple / black spots on the leaves
Magnesium deficiency
This causes less chlorophyll to be made, resulting in yellow leaves (chlorosis)
Nitrate deficiency
Stunted growth
