Chapter 10-Infectious diseases

Question 1

What is an infectious disease

Answer 1

a disease caused by a pathogen and are passed down from an infected to an uninfected person.

Question 2

what is the causative agent of cholera and what type of organism

Answer 2

Vibrio cholerae- bacterium

Question 3

How does the cholera bacterium affect the body

Answer 3

-It acts on the wall of the small intestine where it releases chloride ions
-it reduces the water potential in the gut and leads to severe diarrhoea, dehydration and weakness

Question 4

How can cholera be transmitted

Answer 4

-Through contaminated water
-contaminated food
-not washing hands after visiting the loo
-flies from infected faeces

Question 5

How can we prevent cholera

Answer 5

> > provide adequate sewage infrastructure
provide clean piped water that has been chlorinated
vaccination programmes for countries that have this disease as epidemic

Question 6

treatments to cholera

Answer 6

• Oral rehydration treatment
• antibiotics
• monitoring programmes

Question 7

what is the causative agent for malaria

Answer 7

-Plasmodium:- protoctist
>falciparum
>ovale
>malariae
>vivax

Question 8

Symptoms of malaria:

Answer 8

1-fever
2-shivering
3-anemia
4-headache
5-muscle pain

Question 9

State 3 ways malaria can be transmitted

Answer 9

-insect vector- the female Anopheles mosquitos
-unsterile needles re-used for blood transfusion
-Through the placenta from the mom to child

Question 10

List 3 ways of controlling breeding sites of mosquitos

Answer 10

-Using oil over the surface of water bodies
-Draining marshes
-stocking those sites with fish that eat these mosquito larvae

Question 11

state 3 factors may lead to improvements in controls to malaria

Answer 11

-modern techniques in gene sequencing and drug design
-development of vaccines targeted against the stages of the parasites cycle
-generous donations

Question 12

What is the causative agent of TB and how is it medically diagnosed

Answer 12

Mycobacterium TB
Mycobacterium Bovis
microscopical examination of sputum

Question 13

what are the symptoms of TB

Answer 13

-fever
-weight loss
-coughing blood
-coughing for weeks

Question 14

How can TB be transmitted and spread

Answer 14

-droplets containing the pathogen in the air can be inhaled
-spread of TB in overcrowded areas
-spread of the mycobacterium Bovis from cattle can be spread through contaminated milk and meat

Question 15

where is the site of TB in the body

Answer 15

primary- lungs
secondary-lymph nodes, bones and gut.

Question 16

How can we prevent and control TB

Answer 16

-use of contact tracing
-The BCG vaccine
-pasteurising of milk
-frequent testing of cattle

Question 17

How can TB be treated

Answer 17

-Through isolation and treatments with antibiotics

Question 18

What is the causative agent for HIV/AIDS

Answer 18

-Human immunodeficiency virus

Question 19

List 5 different ways HIV can be transmitted

Answer 19

-Sexual intercourse
-re using of needles
-blood donation
-through placenta
-through breast milk

Question 20

How does HIV affect the body

Answer 20

HIV reduces the number of T-helper cells which results into the body immune system being vulnerable

Question 21

Where is the site of action for the HIV virus

Answer 21

-Brain cells
-T-helper lymphocytes

Question 22

Give 2 reasons why it is difficult to treat HIV

Answer 22

-They have a long latent stage
-They can change their surface proteins and hard to recognise it

Question 23

How can we PREVENT transmission of HIV

Answer 23

-Education people on the dangers
-use of protective wear during sexual intercourse
-encouraging less sharing of needles
-treating pregnant women with drugs
-Blood donations can be screened for HIV and heat treated

Question 24

State 4 ways to CONTROL HIV

Answer 24

-Contact tracing
-screening blood tests
-Encourage high risk groups (LGBTQ+)
-protective sex

Question 25

What do Antibiotics target in bacteria

Answer 25

-Synthesis of bacterial cell wall -Their enzyme action -Their DNA synthesis -Their proteins synthesis -Activity of their proteins

Question 26

why do antibiotics affect bacteria and not viruses

Answer 26

-viruses do not have any cell walls and so cannot be targeted by antibiotics

Question 27

Give the steps on how penicillin affects bacteria

Answer 27

1-When a new bacterial cell is in the process of growing, it releases the enzyme autolysin that creates holes in their cell wall 2-Cross links are formed by peptidoglycan molecules and they end up stretching and growing further 3-Penicillin stops these cross links by inhibiting the enzyme 4-as bacteria live in watery environments their cells absorb water and the cell wall bursts. This means that penicillin only works on a growing bacteria and not when they are fully developed.

Question 28

How do viruses spread around the body

Answer 28

-They use host-cell mechanism for transcription and translation and antibiotics do not bind to the protein of the host cell

Question 29

why isn't penicillin effective in ALL bacteria

Answer 29

-Some bacteria (TB) have thick cell walls -some secrete enzymes that break down the penicillin

Question 30

How does antibiotic resistant bacteria form?

Answer 30

-Due to variation, mutations can occur. -The mutation could cause a change to the nucleotide sequence that could create protein that are unaffected by the antibiotic -As the normal bacteria die, the mutated ones reproduce because of less competition. -Their genes shall pass onto the next future generation

Question 31

Overtime the resistant bacteria become well suited to the environment and their population increases this Is known as:

Answer 31

Evolution by natural selection

Question 32

Give the name of the enzyme that breaks down penicillin

Answer 32

Beta- lactamase

Question 33

Vertical transmission VS Horizontal transmission

Answer 33

Vertical-here the resistant mutation is passed on via binary fusion during replication (asexual) Horizontal- Here the resistant gene is passed on through conjugation whereby bacteria exchange DNA with each other. Plasmids contain the resistant gene and it is shared among others.

Question 34

What are the consequences of antibiotic resistance

Answer 34

- Can create several issues for doctors - Non-pathogenic bacteria could contain the gene and this could pass onto the pathogenic bacteria via horizontal transmission - new antibiotics have to be constantly created

Question 35

what factors have lead to the increase of incidence of resistant bacteria:

Answer 35

- Overuse of antibiotics - wrong prescriptions - large scale use of antibiotics even when animals are not sick - Not completing the full course of antibiotics

Question 36

State 5 ways to reduce the incidence of resistant bacteria

Answer 36

- Making tighter controls on countries with no doctors prescription - Having the patient finish their full course - not using the antibiotics with un-serious infections - the use of narrow spectrum antibiotics ( not widespread antibiotics) - Having more control on antibiotics used in agriculture.

Question 37

List 2 ways that an already resistant bacteria patient can reduce transmission

Answer 37

1-keeping good hygiene e.g washing hands 2-Isolating them.