Communicable diseases Flashcards
What are communicable diseases?
Communicable diseases are diseases that can be spread from one organism to another. They are caused by pathogens such as bacteria, viruses, fungi, and protists. Examples include tuberculosis, influenza, and malaria.
Give three examples of factors other than disease that can cause poor health?
Diet (for example anaemia from little iron and meat) stress and life situations such as location, finances and access to healthcare.
Give three examples of how health problems interact to make each other worse
- Viruses living inside cells can trigger changes in DNA leading to cancers for example HPV and cervical/oral cancer
-Poor immune systems may not be able to fight off pathogens, may contract a communicable disease easier
-Poor mental health have associations to poor physical health, both may also cause each other.
What is Health and what is it when it is described as good?
-A state of physical and mental well-being. Good health is to be free from disease in addition to being physically and mentally well.
What causes communicable diseases?
Pathogens- usually bacteria, viruses and fungi.
Explain the differences between bacteria and viruses
Bacteria are single celled organisms and are much bigger than viruses. Viruses are particles.
Give two ways in which pathogens cause disease
- Bacteria divide rapidly by splitting in two (binary fission). They produce toxins that make us feel unwell and can damage cells.
-Viruses invade body cells, living and reproducing inside them, ultimately leading to their destruction.
Give 3 examples of how diseases (pathogens) are spread
- Airborne; bacteria, viruses and fungi spores carrying through the air, for example in breath droplets. For example, flu, TB and the cold
- Direct contact, for example syphilis and chlamydia spread by touch of the skin. HIV/AIDs through cuts and bodily fluids.
- By water, for example fungal spores in water spreading disease in plants. Or salmonella in contaminated drinking water.
How do we grow microorganisms in the lab?
microorganisms require a culture medium of nutrient gel. This is done by hot agar gel, cooled and set in a petri dish.
Why do we need to grow uncontaminated cultures of microorganisms?
To make sure there isn’t accidental growth of another organism.
Why are cultures refrigerated below 25 degrees?
It slows the growth of pathogens that could potentially be harmful to others.
What did Ignaz Semmelweis do?
Noticed that when women were dying after childbirth, medical students didn’t wash their hands between autopsy and birthing a baby. Suggested doctors and students wash their hands before procedures, reducing the amount of mothers dying from fever following childbirth.
State 3 discoveries about infections in the 1900s
- Louis Pasteur showed microorganisms caused disease, he developed vaccines against diseases such as anthrax and rabies
- Joseph Lister started to use antiseptic chemicals to destroy pathogens before they caused infection in operating theatres
-As microscopes improved, its possible to see pathogens more clearly. This helped convince people that they were really there.
State 3 methods of controlling hygiene measures to prevent disease
- Handwashing after toileting, before cooking
-Using cleaning disinfectants/antiseptics
-Keeping raw meat away from cooked or ready to eat foods.
Besides hygiene, state 3 other means of controlling the spread of diseases and why they help.
-Isolating infected individuals - less contact between infected and non infected individuals
-Destroying vectors of disease - like rats or mosquitoes for malaria so the disease isn’t carried
-Vaccinations - supports the immune system to be prepared for the introduction of a pathogen into the body
Describe what measles is
- Fever and red skin rash
- Spread by cough droplets
-Measles don’t have treatment so vaccinations are relied on
Describe HIV/AIDs
-Symptoms begin mild and dormant like a cold
-HIV attacks the immune system, but initially lay dormant until reactivation
-Eventually the immune system is so overwhelmed it cannot deal with infections and cancers
- Spread by bodily fluids and blood
- Antiretroviral drugs can stop HIV turning to AIDs for many years
Describe tobacco mosaic virus
TMV was the first virus to be isolated. It is a widespread plant pathogen that affects tomatoes and tobacco plants. It causes mosaic pattern discoloration on the leaves. It stops the plant photosynthesising. Spread by diseased plant matter and insects. Needs field hygiene control measures.
Describe Salmonella
- Bacteria found in raw meat and eggs
- Naturally occur in small amounts in the gut, but if ingested and the population becomes too high them they cause salmonella food poisoning
-Often from undercooked food or contaminated cooking utensils
-Symptoms start within 72 hours as abdominal cramps, vomiting and diarrhoea
-symptoms are a result of the toxins of the bacteria
-The dehydration in causes can be fatal in the elderly and the malnourished
-Food separation in cooking of uncooked meats can stop the spread
Describe Gonorrhoea
- a Sexually transmitted disease spread by sexual contact
- Begins with symptoms that then lie dormant. Early symptoms include thick yellow-green discharge from genitalia and pain on urination
-A large proportion of the infected are asymptomatic
-cured with antibiotics, as it is a bacteria. Condoms also help stop the spread as a physical barrier.
Explain some bacterial diseases in plants.
- Agrobacterium tumefaciens bacteria causes crown galls which are masses of unspecialised cells that can grow at the join between the root and shoots of infected plants.
What is rose black spot?
A fungal disease spread by wind and water. It damages leaves so they drop off, affecting growth as photosynthesis is reduced. Spread is controlled by removing affected leaves and chemical sprays.
What are protists?
Single celled organisms that cause a range of diseases in plants and animals. Often involves a living vector that transfers protist to the host. An example is maleria.
What is malaria?
A disease caused by parasitic protists spread by the bite of female mosquitos. It damages blood and liver cells, causes fever and shaking and can be fatal. Early drug treatment are effective. Spread is controlled by using mosquito nets and insecticides to stop mosquito breeding.
