Communicable Diseases Revision Notes
Organisms That Cause Disease
Pathogens
-pathogen is a microorganism that causes disease
-include: bacteria, fungi, viruses and protoctista
-live in is a host which has favourable conditions for the pathogen to survive
-they take nutrients form the host, causing damage to the host in the process
Bacteria
-reproduce rapidly (some every 20 minutes)
-release waste products/toxins damaging cells
-toxins break down the cell membrane, damage inactive enzymes or interfere with genetic material
-plants – live in vascular tissues
Fungi
-animal – live in skin and fungi hyphae grow under the skin and release spores (soreness)
-plants – live in vascular tissue releasing enzymes that digest the tissue, causing decay
Viruses
-invade cells and take over genetic machinery and organelles of cell
-uses the cell to make copies of the virus and the host cell bursts releasing new copies of virus, attacking healthy cells
Protoctista
-enter host cell and feed on contents as they grow causing them to break open
-malaria is caused by a protoctista
Examples of Diseases
Disease in Animals
Name of Disease Characteristics of Disease Organism That Causes Disease
Tuberculosis Affects many parts of the body, killing the cells and Bacteria
tissues; lungs most affected
Bacterial Infection of the meninges – the membranes that Bacteria
Meningitis surround the brain and spinal cord; membranes
become swollen and may cause damage to the brain
and nerves
Ring Rot (in plants) Ring of decay in the vascular tissue of a potato tuber Bacteria
or tomato, with leaf wilting
HIV/AIDS Attacks cells in the immune system and compromises Virus
the immune response
Influenza Attacks respiratory system and causes muscle pains Virus
and headaches
Ringworm (cattle) Growth of fungus in skin with spores cases erupting Fungus
through skin to cause a rash
Athlete’s Foot Growth under skin of feet, particular between toes Fungus
(humans)
Malaria Parasite in the blood that causes headache and fever Protoctista
and may progress to coma and death
Disease in Plants
Name of Disease Characteristics of Disease Organism That Causes Disease
Tobacco Mosaic Causes mottling and discolouration of leaves Virus
Virus
Black Sigatoka Causes leaf spots on banana plants reducing yield Fungus
(bananas)
Blight (tomatoes Affects leaves and potato tubers Protoctista
and potatoes)
Organisms That Cause Disease
Pathogens
-pathogen is a microorganism that causes disease
-include: bacteria, fungi, viruses and protoctista
-live in is a host which has favourable conditions for the pathogen to survive
-they take nutrients form the host, causing damage to the host in the process
Bacteria
-reproduce rapidly (some every 20 minutes)
-release waste products/toxins damaging cells
-toxins break down the cell membrane, damage inactive enzymes or interfere with genetic material
-plants – live in vascular tissues
Fungi
-animal – live in skin and fungi hyphae grow under the skin and release spores (soreness)
-plants – live in vascular tissue releasing enzymes that digest the tissue, causing decay
Viruses
-invade cells and take over genetic machinery and organelles of cell
-uses the cell to make copies of the virus and the host cell bursts releasing new copies of virus, attacking healthy cells
Protoctista
-enter host cell and feed on contents as they grow causing them to break open
-malaria is caused by a protoctista
Examples of Diseases
Disease in Animals
Name of Disease Characteristics of Disease Organism That Causes Disease
Tuberculosis Affects many parts of the body, killing the cells and Bacteria
tissues; lungs most affected
Bacterial Infection of the meninges – the membranes that Bacteria
Meningitis surround the brain and spinal cord; membranes
become swollen and may cause damage to the brain
and nerves
Ring Rot (in plants) Ring of decay in the vascular tissue of a potato tuber Bacteria
or tomato, with leaf wilting
HIV/AIDS Attacks cells in the immune system and compromises Virus
the immune response
Influenza Attacks respiratory system and causes muscle pains Virus
and headaches
Ringworm (cattle) Growth of fungus in skin with spores cases erupting Fungus
through skin to cause a rash
Athlete’s Foot Growth under skin of feet, particular between toes Fungus
(humans)
Malaria Parasite in the blood that causes headache and fever Protoctista
and may progress to coma and death
Disease in Plants
Name of Disease Characteristics of Disease Organism That Causes Disease
Tobacco Mosaic Causes mottling and discolouration of leaves Virus
Virus
Black Sigatoka Causes leaf spots on banana plants reducing yield Fungus
(bananas)
Blight (tomatoes Affects leaves and potato tubers Protoctista
and potatoes)
