Chapter 12 Communicable Diseases Flashcards
What is a disease
What is a communicable disease (2)
Pathogen
Vector
Disease = a condition that impairs normal function
Communicable disease is a disease caused by pathogens , which can be spread by ONE PERSON TO ANOTHER
Pathogens = organisms that cause disease
Vectors are other organisms that carry pathogens from one organisms to another , not being the pathogen themselves
What two ways and how can bacterium be classified ?
1) by shape
- rod shaped = bacilli, spherical , comma shaped , spiralled etc
2) by their CELL WALLS
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Explain how cell walls are different in bacterium and show which positive which negative
Why is it useful to know what wall
- if thick wall (peptidoglycan) , when you stain with Crystal violet , it all absorbs , and so alcohol won’t rinse it off, and so safranin dye counter stain remains masked. = gram positive
- if thin peptidoglycan then won’t absorb that much crystal violet, easily washed by alcohol and saddening red appears = red = negative !
2) different wall cells affect how bacteria react to antibiotics, so if you know you can prepare right type
How bacteria make bad
How often duplicate?
Duplicate every 20 mins and release so many toxins that damage cells like enzymes , cell membranes and disrupts metabolism this way etc
Viruses
How do they operate and make you feel sick
Why they such a good pathogen
Viruses invade living cells, where genetic material they take over biochemistry of the host cell and makes more viruses using their resources. Under stress they will cause cell to burst = make you feel sick
Reproduce insane and adapt and all are pathogenic
What are bacteriophages and what used for
Viruses can even attack bacteria and take over them, these are called bacteriophages.
- people use bacteriophages to IDENTIFY and then treat diseases (as they find the bacteria)
What are protoctista
How make sick
Single celled eukaryotic
- they cause harm by not taking over genetic material but digesting and using cell contents to replicate like malaria
DONT TAKE OVER CELL UNLIKE VIRUS
Fungi
Who do they target and How make sick
Where in organism do they target
How do they wipe out huge areas?
Target plants leaves
- some parasitic : damage by secreting enzymes to digest cell and absorb nutrients - this makes sick
- some release toxins
2) when reproduce produce millions of tiny spores produced , spread huge distances and cause infection
- remember they are saprophytic : digest food by releasing enzymes extracellularly
- attack leaves of plants making them not photosynthesis and die
How do fung
What three diseases caused by bacteria and to what organisms
Tuberculosis = anti mask : human and cow
Bacterial menginitis = human
Ring rot = potatoes and tomatoes
What three disease caused by viruses and what organisms
HIV/ AIDS- humans
Influenza - aniamls like human
Tobacco mosaic virus = plants
What three disease caused by fungi and what organisms
Black Sigatoka = banana plants
Ringworm = cattle
Atheletes foot = humans
Finally two disease caused by proticista and what organisms
Malaria = human
Potato/ tomato late blight = potatoes / tomatoes
What ring rot
What does it do
Any cure?
Bacterial disease
Damages leaves tubers and fruit
Field It cannot be used to grow for 2 years if hit
What is tobacco mosaic virus
What does it do
Any cure/ other solutions
Infects tobacco plants but 150 other species
Damages leaves, flowers in mosaic pattern
No cure = use resistant crops
What is potato blight , tomato blight late blight
What it do
What cure?
Protoctist
Hyphae penetrated cells to destroy leaves etc
No cure but resistant strains
Black Sigatoka
What it do / look like
Cure
Fungus attacks banana
Hyphae penetrate and digest cells making it black
Potential fungicide and resistant strains no cure
Type What does tuberculosis do Link to hiv Cure? Other animals?
Bacteria,
Destroys lung tissue and suppresses immune system , so harder to fight disease
Increase of hiv cause increase here
Treatable by antibiotics (cuz bacteria) and preventable with vaccines
It can affect other animals too like cow
Bacterial meningitis
Type (bruh)
What does it do
Cure?
Bacteria
- attacks meninges of brain that then spreads to rest of body causing blood septicamiea (poisoning )
- antibiotics cure if early and vaccines but very deadly
HIV/ AIDS Type What it do How (brief) Cure
- virus
- AIDS is caused by HIV, targets T helper cells and gradually destroys immune system making people more susceptible to other infections like TB and pneumonia.
- as it is a virus it takes over cell
- no cure but anti - retro viral drugs slow progress and allows more years
Influenza
Type
What it do
Cure + why is flu always here?
Virus
- kills the dilated epithelial cells , which means more chance of infection (no mucus etc)
- kills people due to leaving them susceptible to secondary diseases as a result of reduced protection like pneumonia
No cure , always mutates so immunity only lasts a year, and vaccines need to change all the time .
Malaria
Type
What it do + how
Cure
Protoctist / vector mosquito
- invades red blood cells, liver brain
How = reproduce in mosquitos, then mosquitos bite you and it goes here
- no cure but preventative measures like hygiene can save, remove the mosquito essentially
Ring worm
Type
What it do
Cure
- fungal disease affecting mammals cattle dog human
- grey white, crusty infectious circular areas of skin , not DAMAGING but looks unsightly
- anti fungal creams effective cure so YSS
Athlete foot
Type
What it do / look
Cure
- fungal
- digests warm moist skin between toes, causing cracking and scaling which becomes sore
- spread by formites etc
Cure = yes= anti fungal creams
What are three ways (list) direct transmission of communicable diseases between animals and three indirect
Direct
- direct contact
- inoculation
- ingestion
Indirect
- fomites
- vectors
- droplet infection by inhalation
What 3 ways of Direct contact (disease?)
- kissing or any constant with bodily fluids , includes sexually
- direct skin to skim constant (fungal)
- microorganisms from faeces on hand (diarrhoea )
What is inoculation and three ways (diseases if can)
This is entering external
- through a break in the skin so like intercourse (hiv/aids)
- from an ANIMAL bite (rabies)
- through contaminated needles (septicaemia)
What about Ingestion
- another direct contact happens by eating contaminated food or drink or transferring from food to hand = salmonella, diarrhoea
What are fomites and how indirect
Inanimate objects like towels, cloths, bedding socks etc transfer pathogens ( athelete foot happens like this)
How do vectors do indirect transmission
Water?
- transfers indirectly as it goes from one host to another, like mosquitoes and malaria
- WATER can also be a vector in the case of diarrhoea
Finally how droplet infection easy
Minute bits of droplet when person cough or sneeze can have pathogens that if inhaled by another species can become sick, like influenza, tb
Can diseases be transferred from animal to human?
How in both cases
Yes, in case of H1N1 bird flu etc, prevent this by minimising contact etc
People can also act as vectors for animals, in the case of foot and mouth disease
How do different factors affect the transmission of diseases in animals (3 big ways s,p,c)
Social
- overcrowded and bad living / working conditions increase like TB
- poor healthcare , education etc (more spread and bad hygiene)
- poor disposal waste and hygiene in general
- cultural techniques lead to bad hygeine
Personal
- poor immune system, due to aids or needing immunosuppressive drugs or just bad
- poor diet etc
Climate change
- introduce new vectors and promote current to live over wider area, spreading disease
List direct and indirect transmission for plant
Direct
- simple direct contact, touching other plant if infected = TMV, potato blight, black Sigatoka (fungal again is touch)
Indirect
- soil contamination
- vectors
How does direct transmission lead to disease in plant
If an infected plant , such as with black Sigatoka or potato blight or TMv, makes contact with another plant, it could spread. Also, sap etc can carry
How does soil contamination lead to indirect transmission
Why might you need new soil? Even if plant composts!
Infected plants leave pathogens or reproductive spores of fungi in the soil grown
- if another plant grows here they will become infected
- this typically the bacteria ones like ring rot, but fungal too and TMV
Sometimes you need complete new soil as they can survive composting process too
What types of pathogens are usually spread between mediums
Typically bacterial (ring rot) spread in soil with fungal , fungal (black + Potato) spread by touch and tmv spread everywhere
How do vectors indirectly transmit in plants
1) the WIND acts as one
- carrying fungal spores, but bacteria and viruses too
2) WATER
- spores swim on water on leaves to get around to others , raindrops carry pathogens and spores splash from one plant to next
3) ANIMALS
- insects , birds can carry pathogen from one plant to other , and APHIDS can directly inocculate
4) HUMANS
- transmitted by human hands clothed fomites and farming practices with machines etc
What are factors that affect transmission in plants
- poor farming techniques (not rotating, planting plants susceptible to disease, over crowding, )
- poor mineral nutrition, monoculture etc decreases resistance of plant
- damp warm conditions
CLIMATE CHANGES : increased rainfall and wind promote easier spread of pathogens and spores , allows animal vectors in more places, drier conditions actually reduce
How could a farmer reduced spread of disease (3-4)
- leave plenty room between plants
- clear fields , leave no plant in soil after harvest
- ROTATE CROPS, so least chance host is available for pathogens
- follow strict hyegeine in machinery and handling
Control insect vectors
