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Year 9 disease
Transcript of Year 9 disease
A disease is a condition that prevents or stops the body, or any of its parts, from working well.
Diseases are generally grouped into two types:
What are the causes of infectious disease?
Infectious diseases are generally caused by microbes known as
that invade the body and stop it working properly.
When an infection occurs
kicks in and defends the body against diseases. However, the immune system is not almighty and may require time to be effective. Then the
of the disease will appear on the host.
Infectious diseases are those that can be spread or transferred from one organism to another. The common cold, influenza and chickenpox are all common infectious diseases.
The animal or plant that the pathogen has invaded is called the
Chicken pox virus (pathogen)
Many infections are not THAT direct!
Anopheles mosquito (vector)
Malaria is a deadly disease passed onto humans by mosquitoes.
Some diseases require an organism, known as a
, to pass onto another organism (host) to infect the host. A common disease vector for humans is the mosquito.
s - a physical or mental feature that is regarded as indicating a condition of disease
Symptoms of malaria: Fever
Nausea and vomiting
This type of disease cannot be 'caught' because there is no pathogen 'germ' involved.
There is a huge variety of non-infectious diseases. They can be due to not eating a healthy diet, or being exposed to dangerous radiations or chemicals. Some are caused by malfunctions within your body organs or cells.
Meet the pathogens
is a living organism which has invaded your body and is attacking your cells and organs, or is living within you and producing toxic chemicals which make you sick. An
means that it is
(meaning the disease can be passed on from one living thing to another). You catch an infectious disease when you are
by a pathogen.
Pathogens are generally grouped into 4 types:
Bacteria are all unicellular, and have very small cells in a variety of shapes. Some bacteria are pathogens. They can breed quickly in your body and either damage your cells directly, or release toxins to harm your cells. Bacterial infections can be treated with antibiotics.
Viruses are the smallest of all, and are not quite living things. Each virus is a tiny ball of protein with some genetic substances inside. Viruses function by "taking" over living cells and forcing cells to kill themselves to make new viruses.
Protozoa are unicellular and have animal like cells. Compared to bacteria, not many diseases are caused by protozoan pathogens. Mostly occur in tropical areas.
While most fungi are harmless decomposers in the soil (e.g.: mushrooms), there are a few that cause diseases. Fungi mostly affect the skin, hair and nails.
E.g. Flu, Measles and Mumps
E.g. Trichophyton rubrum that causes Athlete's foot
Parasites are animals or plants which must live on or in another plant or animal to survive (go on living).
A pandemic is the case where an infectious disease has spread through human populations across a large region; for instance multiple continents, or even worldwide. Throughout history, the disease smallpox was considered a pandemic. Recently, H1N1 (swine flu) that occurred in 2009 was also considered a pandemic.
-In groups of 3 or 4 ( people sitting next to you),
a pathogen that can infect a host and give it a disease.
Include:-Give the pathogen a name and say what it is (bacteria or etc)
-Choose a host (can be an animal or plant)
-Invent a disease (again, give it a name) and describe how it affects the host as well as the symptoms it will show
-A vector/vectors in which the pathogen can spread. Describe the vector spreading process
-Diagram of what the pathogen would look like