3.1 Communicable Diseases Flashcards
Completed | T3 Infection and Response | Physiscsandmathstutor
What is a communicable disease?
An infectious disease that spreads through the transfer of pathogens between animals or plants e.g. flu.
What is a non-communicable disease?
A disease that cannot be transmitted from person to person e.g. cancer.
What are pathogens?
Microorganisms that cause infectious disease.
What are the types of pathogens?
Viruses, Bacteria, Fungi, Protists.
How do bacteria cause disease?
Once inside the body, they reproduce rapidly (binary fission), produce chemicals called toxins, and toxins damage tissues and make us feel ill.
How do viruses cause disease?
They invade host cells and reproduce within it, causing cell damage. Once the virus leaves the cell, it may burst and die.
What are the ways in which pathogens can be spread? (3)
- In the air - flu, tuberculosis and the common cold are spread by [water] droplet infections.
- In water - fungal spores in water spread plant diseases.
- By direct contact - common in plant diseases and sexually transmitted infections.
What are the ways in which the spread of pathogens can be reduced? (4)
- Hygiene - hand-washing, disinfectants, tissues.
- Reducing contact with infected individuals - quarantine.
- Removing vectors - use of pesticides and insecticides, removal of habitats.
- Vaccination.
Why is it especially important to prevent the spread of viral diseases?
Scientists have not yet developed cures for many viral diseases, which cannot be killed using antibiotics.
What is measles?
Measles is a serious viral disease that can cause blindness and brain damage.
What are the symptoms of measles?
The first symptom is often a fever followed by a red skin rash after around 3 days.
How is measles spread?
By air - through the inhalation of droplets from coughs and sneezes.
How are measles prevented?
Vaccination of young children.
What is HIV / AIDS?
- HIV: a virus which attacks and damages the immune system until it can no longer function properly.
- AIDS: the condition resulting from a long-term HIV infection.
How is HIV spread?
- Direct sexual contact.
- Exchange of bodily fluids eg. blood, breastmilk.
How can the spread of HIV/AIDS be prevented? (5)
- Use of condoms
- Screening of blood for transfusions
- Not sharing needles
- Bottle-feeding by HIV-positive mothers
- Lifelong use of antiretroviral drugs to prevent the
development of AIDS
What is salmonella?
A disease caused by ingesting a type of bacteria found in raw meat, poultry and eggs, which causes food poisoning. It may be fatal in very young or elderly individuals due the risk of dehydration.
What are the symptoms of salmonella food poisoning? (4)
- Fever
- Abdominal cramping
- Vomiting
- Diarrhoea
How can the spread of salmonella be limited? (4)
- Vaccinating animals intended for consumption.
- Keep raw meat away from cooked meat.
- Disinfect hands and surfaces after contact with
raw meat. - Thoroughly cook meat.
What is gonorrhoea?
A sexually transmitted disease (STD) caused by unprotected sex with an infected individual.
What are the symptoms of gonorrhoea?
Early symptoms include yellow/green discharge from genitals and painful urination, although it may be symptomless.
How can gonorrhoea be treated?
Antibiotics (no longer penicillin as many strains are resistant).
How can the spread of gonorrhoea be limited?
- Using a condom.
- Getting tested before unprotected sex to kill the bacteria.
What is malaria?
Malaria is a disease caused by protist pathogens which may be fatal in some cases.
What are the symptoms of malaria?
Repeated bouts of fevers and shaking.
How is malaria spread?
Protists (the disease is carried from host to host by mosquitoes, and the protists enter the human bloodstream when they feed).
How can the spread of malaria be reduced? (4)
- Prevent mosquito breeding by removing stagnant
water - Using insecticides
- Using mosquito nets to avoid bites
- Antimalarial drugs
What are insecticides?
Pesticides used to kill insects.
What is tobacco mosaic virus (TMV)?
A plant pathogen affecting many species of plants e.g. tomatoes causing a ‘mosaic’ pattern of discolouration on leaves when cells are damaged, which cannot photosynthesise.