3.1 communicable diseases Flashcards
what is a communicable disease?
A disease caused by a pathogen which cane be passed between animals or plants e.g. flu.
What is a pathogen?
A disease-causing microorganism e.g. 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 three ways in which pathogens can be spread
- by air (flu, tuberculosis, common cold)
-by water (fungal spores in water spread plant diseases)
-by direct contact (common in plant diseases and sexually transmitted infections)
what is a vector?
organism that does not cause disease itself but which spreads infection by conveying pathogens from one host to another.
why is it especially important to prevent the spread of viral diseases
scientists have not yet developed cures for many viral diseases
Give four ways in which the spread of pathogens can be reduced
-Hygiene (handwashing, disinfectants, tissues)
-Reducing contact with infected individuals (quarantine)
-removing vectors (pesticides and insecticides, removal of habitats
-vaccination
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- through the inhalation of droplets from cough and sneezes. there is no specific treatment for measles once it occurs
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 e.g. blood, breastmilk.
How can the spread of HIV/AIDS be prevented?
-use of condoms
-screening of blood 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 plant pathogen which causes leaf discolouration when cells are damaged. affected areas cannot photosynthesise, reducing the crop yield. As there is no treatment, farmers grow TMV-resistant crop strains to avoid infections.
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.
what are the symptoms of salmonella food poisoning?
-Fever
-abdominal cramping
-vomiting
-diarrhoea
May be fatal in very young or elderly populations due to the risk of dehydration
How can the spread of salmonella be limited?
-vaccinating animals intended for consumption
-keep raw meat away from cooked meat
-disinfect hands and surfaces after contact with raw meat
-thoroughly cook meat