Chapter 10-Infectious diseases Flashcards
What is an infectious disease
a disease caused by a pathogen and are passed down from an infected to an uninfected person.
what is the causative agent of cholera and what type of organism
Vibrio cholerae- bacterium
How does the cholera bacterium affect the body
-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
How can cholera be transmitted
-Through contaminated water
-contaminated food
-not washing hands after visiting the loo
-flies from infected faeces
How can we prevent cholera
> > provide adequate sewage infrastructure
provide clean piped water that has been chlorinated
vaccination programmes for countries that have this disease as epidemic
treatments to cholera
- Oral rehydration treatment
- antibiotics
- monitoring programmes
what is the causative agent for malaria
-Plasmodium:- protoctist
>falciparum
>ovale
>malariae
>vivax
Symptoms of malaria:
1-fever
2-shivering
3-anemia
4-headache
5-muscle pain
State 3 ways malaria can be transmitted
-insect vector- the female Anopheles mosquitos
-unsterile needles re-used for blood transfusion
-Through the placenta from the mom to child
List 3 ways of controlling breeding sites of mosquitos
-Using oil over the surface of water bodies
-Draining marshes
-stocking those sites with fish that eat these mosquito larvae
state 3 factors may lead to improvements in controls to malaria
-modern techniques in gene sequencing and drug design
-development of vaccines targeted against the stages of the parasites cycle
-generous donations
What is the causative agent of TB and how is it medically diagnosed
Mycobacterium TB
Mycobacterium Bovis
microscopical examination of sputum
what are the symptoms of TB
-fever
-weight loss
-coughing blood
-coughing for weeks
How can TB be transmitted and spread
-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
where is the site of TB in the body
primary- lungs
secondary-lymph nodes, bones and gut.
How can we prevent and control TB
-use of contact tracing
-The BCG vaccine
-pasteurising of milk
-frequent testing of cattle
How can TB be treated
-Through isolation and treatments with antibiotics
What is the causative agent for HIV/AIDS
-Human immunodeficiency virus
List 5 different ways HIV can be transmitted
-Sexual intercourse
-re using of needles
-blood donation
-through placenta
-through breast milk
How does HIV affect the body
HIV reduces the number of T-helper cells which results into the body immune system being vulnerable
Where is the site of action for the HIV virus
-Brain cells
-T-helper lymphocytes
Give 2 reasons why it is difficult to treat HIV
-They have a long latent stage
-They can change their surface proteins and hard to recognise it
How can we PREVENT transmission of HIV
-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
State 4 ways to CONTROL HIV
-Contact tracing
-screening blood tests
-Encourage high risk groups (LGBTQ+)
-protective sex
What do Antibiotics target in bacteria
-Synthesis of bacterial cell wall
-Their enzyme action
-Their DNA synthesis
-Their proteins synthesis
-Activity of their proteins
why do antibiotics affect bacteria and not viruses
-viruses do not have any cell walls and so cannot be targeted by antibiotics
Give the steps on how penicillin affects bacteria
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.
How do viruses spread around the body
-They use host-cell mechanism for transcription and translation and antibiotics do not bind to the protein of the host cell
why isn’t penicillin effective in ALL bacteria
-Some bacteria (TB) have thick cell walls
-some secrete enzymes that break down the penicillin
How does antibiotic resistant bacteria form?
-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
Overtime the resistant bacteria become well suited to the environment and their population increases this Is known as:
Evolution by natural selection
Give the name of the enzyme that breaks down penicillin
Beta- lactamase
Vertical transmission VS Horizontal transmission
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.
What are the consequences of antibiotic resistance
- 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
what factors have lead to the increase of incidence of resistant bacteria:
- Overuse of antibiotics
- wrong prescriptions
- large scale use of antibiotics even when animals are not sick
- Not completing the full course of antibiotics
State 5 ways to reduce the incidence of resistant bacteria
- 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.
List 2 ways that an already resistant bacteria patient can reduce transmission
1-keeping good hygiene e.g washing hands
2-Isolating them.
