Communicable diseases Flashcards
What is a communicable disease?
A disease caused by a pathogen which can be passed between animals or plants such as the flu.
What is a pathogen?
A disease-causing microorganism such as bacteria.
How do bacteria cause disease?
Once inside the body, they divide rapidly by binary fission. They kill cells and produce harmful toxins.
How do viruses cause disease?
They invade and reproduce inside living body cells, leading to cell damage.
Give 3 ways in which pathogens can be spread
- By air: flu, tuberculosis and the common cold are spread by droplet infection.
- By water: fungal spores in water spread plant diseases.
- By direct contact: common in plant diseases and sexually transmitted infections.
Give 4 ways in which the spread of pathogens can be reduced
- Hygiene: handwashing, disinfectants, tissues.
- Reducing contact with infecting individuals: quarantine.
- Removing vectors: use of pesticides and insecticides, removal of habitats.
- Vaccination.
Why is it especially important to prevent the spread of viral disease?
Scientists may have not yet developed cures for many viral diseases.
What is measles?
Measles is a serious viral disease that can cause blindness and brain damage. The main symptoms are a fever and a red skin rash.
How is measles spread?
By air - though the inhalation of droplets from coughs and sneezes.
What is HIV/AIDS?
HIV is a virus which attacks and damages the immune system until it can no longer function properly. AIDS is the condition resulting from a long-term HIV infection. There is no cure or vaccine for HIV/AIDS.
How is HIV spread?
Direct sexual contact and the exchange of bodily fluids such as blood and breastmilk.
How can the spread of HIV/AIDS be prevented?
- Use of condoms.
- Screening of blood for transfusions.
- Not sharing needles.
- Bottle-feeding by HIV-positive mothers.
- Use of antiretroviral drugs to prevent the development of AIDS.
What is tobacco mosaic virus?
A viral plant disease which causes leaf discolouration when cells are damaged. Affected areas cannot photosynthesise, reducing the crop yield. As there is no treatment, farmer grow TMW-resistant crop strains to avoid infection.
How is tobacco mosaic virus spread?
Contact between infected and healthy plants. Insects may act as vectors which transfer the virus between different plants.
What is salmonella?
A type of bacteria found in raw meat, poultry and eggs. If they enter the body via food poisoning, they can affect natural gut bacteria.