Communicable diseases

pathogens

microorganisms that cause communicable disease

What are the four main types of pathogens?

• bacteria

• viruses

• protists

• fungi

bacteria

• very small cells (1/100th the size of body cells) which reproduce rapidly inside body

  • can make you feel ill by producing toxins that damage cells and tissue

viruses

• not cells and are 1/100th size of bacteria

  • live inside cells and replicate themselves using cell’s machinery to produce many copies of themselves

    • these cells burst releasing the new viruses + this damage makes you feel ill

protists

• eukaryotes + mostly single-celled

  • some are parasites that live on or inside other organisms and cause them damage

  • often transferred to the organism by vector

fungi

• some single celled while others have body made of thread-like structures called hyphae

  • they can grow + penetrate human skin and surface of plants

  • can produce spores which spread

Three ways pathogens can spread

• water

• air

• direct contact

What type of pathogen is measles caused by, and what is its symptoms and prevention?

• virus

• red skin rash, signs of fever, coughing, sneezing

• vaccinated against measles when young

What type of pathogen is HIV caused by, and what is its symptoms and prevention?

• virus

• flu-like symptoms initially

• antiretroviral drugs to stop virus from replicating, reduce sexual contact

What type of pathogen is tobacco mosaic virus caused by, and what is its symptoms and prevention?

• virus

• mosaic pattern on leaves of plants, leaves become discoloured

• destroy plant and anything that has come in contact with it

What type of pathogen is rose black spot caused by, and what is its symptoms and prevention?

• fungus

• black/purple spots to develop on leaves, leaves turn yellow and drop

• using fungicides, stripping plant of affected leaves

What type of pathogen is malaria caused by, and what is its symptoms and prevention?

• protist

• fever

• stopping mosquitoes from breeding, mosquito nets, spraying insect repellent

What type of pathogen is salmonella food poisoning caused by, and what is its symptoms and prevention?

• bacteria

• stomach cramps, fever, vomiting, diarrhoea

• most poultry given vaccination against salmonella in U.K

What type of pathogen is gonorrhoea caused by, and what is its symptoms and prevention?

• bacteria

• pain when urinating, thick yellow/green discharge from vagina or penis

• originally treated with antibiotic - pencillin - but strains of bacteria became resistant, can be treated with antibiotics or barrier methods of contraception