communicable disease Flashcards
name for the 4 types of pathogens
bacteria, viruses, fungi and Protoctista
give some information on bacteria
they are classified based on shape and/or cell wall
no membrane bound organelles
prokaryotes
produces toxins that poison/damage host cells. can break down the cell membrane, inactivate enzymes or interact with genetic information and prevent cell division.
give some information on viruses
0.02-0.3um
non living agent
DNA or RNA surrounded by a protein.
reproduce rapidly and take of the biochemistry of the host cell.
good at developing adaptations to treatments
can attack bacteria forming bacteriophages
ULTIMATE PARASITE
take over the cell metabolism and genetic information. then reproduces rapidly. cell bursts open and spread to other cells to cause infection.
give some information on Protoctista
eukaryotes
single or multi cellular
disease causing Protoctista use animals as a host and require a vector to transfer them
digest and use cell component to reproduce.
give some information on
eukaryotes
multicellular
can PHS and digest food extracellularly
saprophytes - feed on dead matter
when they reproduce the make millions of spores which can spread far and rapidly.
digest living cells, destroying them. can also release toxins.
explain a type of staining that enable you to identify the type of cell wall in a prokaryote
Gram staining
gram positive - purple/blue under the microscope. ie MRSA
gram negative - red under the microscope ie e.coli
this is useful because it indicates which antibiotics will be most effective when reacting with the pathogen based on the cell wall.
what is a communicable disease
caused by pathogens and can be passed on from one organism to another causing disease.
give an example of a bacteria disease in plants
ring rot
gram positive bacteria
affects potatoes and tomato’s
effects the entire field so it cannot be used to grow crops for at least 2 years after the infection.
give an example of a viral disease in plants
TMV (Tobacco mosaic virus)
affects tomatoes and peppers
stunts growth and reduces yield
no cure but resistant crop stains are available
give an example of a Protoctista disease in plants
potato blight
cell body penetrates the host cell, destroying leaves.
no cure but resistant strains and careful management of chemical treatments can reduce infection
give an example of a fungal disease in plants
black sigatoka
bananas
cell body penetrates and digests leaves and cells causing them to turn black.
resistant strains are being developed.
no cure but fungicide treatment can reduce the spread.
give an example of a bacteria disease in animals (2)
tuberculosis TB
humans, cows, badgers and pigs
damages and destroys lung tissue supressing the immune system so less able to fight off infection.
curable by antibiotics and preventable by improved living conditions
meningitis
attacks the protective membranes in the brain
can spread to other parts of the body causing blood poisoning
effects mostly young children and teenagers
glass test - red, purple rash that will not disappear when pressure is applied.
vaccines and antibiotics if caught early enough are used as treatments
give two examples of viral diseases
HIV AIDS targets T helper cells in the immune system so people are open to other infections
it is a retrovirus with RNA which transcribes into a single strand of DNA invading the host cell genetic material.
passed from person to person through bodily fluids ie sex, exchange of needles, some unsterile medical practices, mother to baby during breast feeding.
no vaccine and no cure but anti retroviral drugs can slow down the progress of the disease.
influenza effects the ciliated epithelial cells in gas exchange system. it kills them leaving the airways open to secondary infection. can be fatal in young, old and vulnerable people. having the flu one year will leave you with immunity for the next due to the small changes of the antigens on the plasma membrane. occasionally there will be big changes on the surface of the virus which will lead to an epidemic/pandemic as there are no antibodies available.
Zootonic influenza is caught from animals.
give one protocitista disease
malaria - spreads through the bite of a female mosquito (Anopheles) when feeding on humans for blood caused by the pathogen Plasmodium it can invade RBC, liver and the brain. the disease makes people weak and vulnerable to other infections
no vaccine and limited cures but preventative measures can be effective.
using mosquito nets, insecticides, removing standing water, long sleeve clothes and keeping doors and windows shut.
how do you identify pathogens
- pathogens are cultured in the lab and identified with a microscope
-monoclonal antibodies can be used to identity - DNA sequencing technology means pathogens can be identified down to a single mutation.
how do you identify pathogens
- pathogens are cultured in the lab and identified with a microscope
-monoclonal antibodies can be used to identity - DNA sequencing technology means pathogens can be identified down to a single mutation.
give three direct ways that pathogens can be spread in animals
direct contant ie kissing, touching, transmitting faeces on hands
inoculation (break of the skin) ie sex, animal bite or puncture wounds (through sharing needles)
ingestions ie contaminated food or drink
give 3 examples of how pathogens can be indirectly transmitted
fomites inanimate objects sich as bedding and socks ie athletes foot
give 3 examples of how pathogens can be indirectly transmitted
fomites inanimate objects sich as bedding and socks ie athletes foot
droplet saliva and droplets are expelled from your mouth as you talk.
vectors transferred pathogen to a host
water can also be a vector
give 2 fungal diseases
ring worm and athletes foot
how are pathogens transmitted between plants
direct contact with unhealthy plant
soil contamination left behind by infected crops can often effect the next crop.
vectors ie the wind, water splashes, animals and humans