Causes of infectious disease

Question 1

What is an infectious disease?

Answer 1

A condition that adversely affects the normal functioning of an organism or parts of an organism

Question 2

Difference between infectious and non infectious disease?

Answer 2

• Infectious diseases are caused by pathogens and can be transmitted from one organism to another
• non infectious that are not caused by pathogens and are not contagious

Question 3

What are pathogens?

Answer 3

Any organism that is capable of causing disease in its host

Question 4

What are the types of pathogens?

Answer 4

Bacteria, viruses, fungi, protozoans, prions

Question 5

What is virulence?

Answer 5

the degree of pathogenicity or the degree of which a pathogen can cause disease in its host

Question 6

What is the difference between sign vs symptom?

Answer 6

• Sign= objectively measurable factors such as increased body temperature, rash, hypertension
• symptom: factors reported by a patient such as pain, fatique, nausea

Question 7

What is pathogenicity?

Answer 7

The ability of a pathogen to cause disease in a host.

Question 8

What is bacteria

Answer 8

Unicellular, prokaryotic organisms which do not contain membrane bound organelles

Question 9

How do bacteria cause disease?

Answer 9

producing toxins or chemicals that harm the host’s bodies or by direclting invading host tissues and causing damage

Question 10

How is bacterial diseases treated?

Answer 10

Chemical treatment with antibiotics, surgical removal of dead issue, wound cleansing

Question 11

What is fungi

Answer 11

• Eukaryotic organisms with a cell wall comprised of chitlin
• can be unicellular or multicellar
• not capable of producing own nutrients- heterotrophic
• most fungi live on dead plant and animal material- role as decomposer

Question 12

What is an example of a unicellular fungi and a multicellular fungi

Answer 12

yeasts- unicellular
moulds- multicellular

Question 13

What is protozoa

Answer 13

• unicellular eukaryotic organisms
• no cell wall
• binary fission
• Live in the human gastrointestinal tract and pools and sewages

Question 14

Common diseases caused by protozoa

Answer 14

• malaria
• amoebic dysentery

Question 15

Macroorganisms (macroparasites)

Answer 15

• multicellular eukaryotic organisms
• visible to naked eye
• classifed into two groups; endoparasites and ectoparasites
• some cause disease directly
• others act as vectors

Question 16

List from the smallest to largest pathogens

Answer 16

Prions, viruses, bacteria, protozoa, fungi macroparasites

Question 17

List some examples of diseases caused by bacteria

Answer 17

• Tuberculosis
• Pneumonia
• tetanus
• dysentery

Question 18

Common diseases caused by fungi

Answer 18

• Thrush
• Ringworm

Question 19

Examples of macroparasites

Answer 19

Endoparasites: tapeworms
Ectoparasites: ticks, fleas,mites

Question 20

What is a virus

Answer 20

• A microscopic pathogen that consist of RNA or DNA that is enclosed by a protective protein coat

Question 21

What is a capsid

Answer 21

The protective protein coat that surrounds the genetic material of a virus.

Question 22

Antivirals

Answer 22

Medications or substances used for the treatment of viral infections by inhibiting the replication of viruses

Question 23

Retroviruses

Answer 23

Viruses that contain RNA as their genetic material

Question 24

What are the living Characteristics of Viruses

Answer 24

Viruses possess genetic material (DNA or RNA) that allows them to pass on genetic information

Question 25

Non-living Characteristics of Viruses

Answer 25

iruses are not composed of cells and can be crystallized. They rely on a host cell for reproduction and metabolism.

Question 26

Size of Viruses

Answer 26

Viruses are smaller than 500 nm in size, making them visible only under an electron microscope.

Question 27

What is the infectious part of a virus?

Answer 27

the genetic material (DNA or RNA) enclosed within the capsid.
It carries the genetic info for the virus to replicate and infect host cells.

Question 28

What are the steps for virus replication?

Answer 28

1. The virus attaches to the surface of a host cell.
2. The virus enters the host cell and releases its genetic material. (nucleic acids)
3. The viral genetic material takes control of the host cell’s machinery and begins to replicate viral genetic materia
4. New viruses are synthesised from proteins
5. The host cell is destroyed or ruptured to release the newly formed virisues
6. Newly released virions infect other host cells and process repeats

Question 29

What are diseases caused by viruses

Answer 29

• measles
• influenza
• AIDs (HIV)
• herpes
• chicken pox

Question 30

What are pathogenic prions

Answer 30

• smallest type of pathogen
• Abnormal type of protein that can cause disease in mammals
• contains no genetic material

Question 31

Which body systems are mostly affected by pathogenic prions?

Answer 31

The nervous system, including the brain, nerves, and spinal cord.

Question 32

How do pathogenic prions cause disease?

Answer 32

When an abnormal prion comes into contact with a normal prion, it can trigger it to fold abnormally and clump in the brain

Question 33

What happens to brain tissue affected by pathogenic prions?

Answer 33

Brain tissue becomes filled with holes, giving it a sponge-like appearance.

Question 34

How are diseases caused by pathogenic prions referred to?

Answer 34

They are called transmissible spongiform encephalopathies.

Question 35

Where are normal prions found in organisms?

Answer 35

Brain and spinal cord

Question 36

Examples of diseases caused by prions

Answer 36

• mad cow disease
• CJD

Question 37

What are some ways in which pathogenic prions can be transmitted?

Answer 37

• Ingesting tissue containing prions,
• using contaminated surgical equipment
• inheriting a mutated gene for infected prions
• receiving contaminated growth hormone injections
• infected corneal implants from donors.