4.1.1 a communicable diseases Flashcards
what is the shape and function of cocci?
small and round
less surface area so can survive in dryer environments
what is the shape and function of spirillum?
spiral cells
move in a corkscrew motion so meet less resistance from surrounding water
what is the shape and function of bacilli and vibrio?
greater surface area to volume ratio so can easily take up nutrients from dilute solutions
shaped like tubes with rounded ends
how long does it take for one bacterium to replicate?
20 minutes
how do bacteria reproduce and why?
binary fission
no nucleus so mitosis doesn’t occur
what are the problems of bacteria reproducing so quickly?
food spoils quickly
spread of disease can happen faster
how do bacteria cause disease?
produce toxins which causes symptoms by cell damage eg cell membranes, enzymes or genetic material
what happens during the lytic cycle?
the virus attaches to a specific host cell
genetic material from virus is injected into host cell
viral genes cause the host cell to make new viruses
host cell splits open releasing the new viruses and killing the cell
what is a phage?
virus that infects and replicates within bacteria and archaea
what is the lysogenic cycle?
phage infects a bacterium and inserts its DNA into the bacterial chromosome allowing the phage DNA to be copied and passed on along with the cell’s own DNA
what type of pathogen causes tuberculosis?
Mycobacterium tuberculosis
which is a bacterium
what organisms are affected by tuberculosis?
humans, cows, pigs, badgers, deer
how is tuberculosis spread?
through the air from one person to another
what are the symptoms of tuberculosis?
damages and destroys lung tissue and suppresses the immune system
cough that lasts more than 3 weeks
feeling tired
high temperature
loss of appetite and weight loss
how is tuberculosis prevented and cured?
prevented by improving living standards and vaccinations
cured by antibiotics
what is type of pathogen is bacterial meningitis caused by?
commonly caused by Streptococcus pneumonia which is a bacterium
what organisms are affected by bacterial meningitis?
humans
how is bacterial meningitis spread?
from person to person through the droplets of respiratory or throat secretions
what is bacterial meningitis an infection of?
the meninges of the brain which can spread to the rest of your body causing blood poisoning and rapid death
what are the symptoms of bacterial meningitis?
blotchy red rash that does not disappear when you press a glass to it
how can bacterial meningitis be prevented?
vaccines can prevent some forms
what type of pathogen causes ring rot?
Clavibacter michiganensis which is a bacterium
what organisms are affected by ring rot?
potatoes
tomatoes
aubergines
how is ring rot spread?
contact with infected tubers particularly if tuber is damaged
what are the symptoms of ring rot?
damages leaves, tubers and fruit and can destroy up to 80% of the crop
what is the cure for ring rot?
no cure
what type of pathogen causes AIDS?
Human immunodeficiency virus which targets T helper cells in the immune system of the body
what organisms are affected by AIDS?
humans
chimpanzees
gibbon apes
rabbits
how is AIDS spread?
from body fluids of an infected person including blood, breast milk, semen and vaginal fluids
what does AIDS do to the body?
gradually destroys immune system so affected people are open to other infections like TB, pneumonia and some types of cancer
how is AIDS prevented and cured?
no vaccines and no cure but anti-retrovirol drugs slow down the progress of the disease
what is influenza caused by?
influenza virus
what organisms are affect by the influenza virus?
humans
pigs
chickens
how is influenza spread?
virus is spread through droplets
what does the influenza do to the body?
kills the ciliated epithelial cells leaving the airways open to secondary infection
severe secondary bacterial infections can occur on top of the original viral infection
what type of pathogen causes tobacco mosaic virus?
viral plant pathogen
what organisms does tobacco mosaic virus affect?
tobacco plants and around 150 other species
how is tobacco mosaic virus spread?
infected plants rubbing against healthy plants or contaminated tools or workers hands
what does tobacco mosaic virus do to the plants?
damages leaves, flowers and fruit
stunts growth and reduces yields
can lead to almost total crop loss
what is the cure for tobacco mosaic virus?
no cure but resistant strains are available
what type of pathogen caused malaria?
protoctist plasmodium
what does organisms does malaria affect?
reptiles
birds
mammals
what spreads malaria?
bite of an infected female Anopheles mosquito
what does malaria do to the infected organism?
makes organism weak and vulnerable to other infections
how is malaria cured and prevented?
no vaccine and limited cures
what are the symptoms of malaria?
high temperature
headaches
feeling very tired
muscle pains
what type of pathogen causes potato/tomato blight?
caused by a water mould which is a fungus-like protoctist
what organisms are affected by the potato blight?
potatoes
tomatoes
aubergines
other members of the potato family
how is potato blight spread?
carried by the wind and the rain
what does potato blight do to the organism?
hyphae penetrate host cells and destroys leaves, tubers and fruits
how do we cure and prevent potato blight?
no cure but resistant strains exist and chemical treatments can reduce infection risk
what type of pathogen causes black Sigatoka?
Mycosphaerella fijiensis which is a fungus
what organisms does black Sigatoka affect?
banana
how is black Sigatoka spread?
rain splashes and wind bone spores during wet, humid, windy conditions
what does black Sigatoka do to the organism affected?
hyphae penetrate and digest cells which turn the leaves black
how is black Sigatoka cured and prevented?
no cure but resistant strains are being developed
fungicide treatment and good husbandry can control the spread of the disease
what type of pathogen causes ringworm?
fungi called Trichophyton
what organisms does ringworm affect?
dogs
cattle
cats
sheep
goats
pigs
rodents
rabbits
birds
humans
how is ringworm spread?
contact with objects or surfaces that an infected person or animal has touched or rubbed against
what are the symptoms of ringworm?
causes grey-white, crusty, infectious circular areas of skin
rash my be scaly, dry, swollen or itchy
what is the cure for ringworm?
anti fungal creams
what type of pathogen causes athletes foot?
fungi called Tinia pedia
what organisms are affected by athletes foot?
humans
how is athletes foot spread?
through contact with contaminated surfaces
what are the symptoms of athletes foot?
ringworm that grows on and digests the warm, moist skin between the toes
causes cracking and scaling which is itchy and sore
what is the cure for athletes foot?
anti fungal creams
