12.2 ANIMAL AND PLANT DISEASES Flashcards
what is ring rot?
- bacterial disease of potatoes, tomatoes, and aubergines
- caused by Gram Positive Bacterium
- damages leaves, tubers and fruit
- if infects a field, cannot be used to grow potatoes again for 2+ years
what is tobacco mosaic virus (TMV)?
- virus that infects tobacco plants and 150 other species of plant
- damages leaves, flowers and fruit
- stunts growth and reduces yields
- can lead to an almost total crop loss
- no cure, but are resistant crop strains available
what is potato blight?
- caused by fungus-like protoctista
- penetrate host cells, destroy leaves, tubers and fruit
- no cure, but resistant strains, careful management and chemical treatments can reduce infection risk
what is black sigatoka?
- banana disease
- caused by fungus
- attacks and destroys leaves
- hyphae penetrate and digest cells, turning leaves black
- fungicide treatment can control spread, but there’s no cure
what is tuberculosis?
- bacterial disease of humans, cows, pigs, badgers and deer
- damages and destroys lung tissue and supresses the immune system
- people infected by HIV/AIDS are more likely to have TB infections developed
- both curable (antibiotics) and preventable (vaccination and improved living standards)
what is bacterial meningitis?
- bacterial infection of the meningitis of the brain (protective membranes on the surface of the brain)
- can spread to the rest of the body causing septicaemia (blood poisoning) and rapid death
- mainly affects very young children, and teenagers
- different symptoms for each age group, both have blotchy red/purple rashes that don’t disappear if a glass is pressed against it
- antibiotics can cure the disease if delivered early
- vaccines can protect against some forms
what is human immunodeficiency virus/ acquired immunodeficiency syndrome?
- AIDS is caused by HIV, which targets T helper cells in the immune system
- it gradually destroys the immune system so infected people are open to other infections
- can infect humans and some non-human primates
- no vaccine and no cure
- anti-retroviral drugs can slow process of the disease
how is HIV spread?
passed from one person to another through bodily fluids, most commonly through:
- unprotected sex
- shared needles
- contaminated blood products
- from mothers to their babies during pregnancy, birth or breast feeding
what is HIV?
- HIV is a retrovirus with RNA as its genetic material
- it contains enzyme reverse transcriptase, which transcribes the RNA to a single strand of DNA in the host cell
- this genetic material interacts with the genetic material of the host cell
what increases infection rate of HIV?
- female genital mutilation
what is influenza (flu)?
- viral infection of ciliated epithelial cells in the gas exchange system
- kills cilia, leaving airways open to secondary infection, such as pneumonia which can be deadly
- can be fatal, especially to young children, elderly and those with chronic illnesses
- affects mammals, including humans
- 3 main strains - A, B and C.
- mutate regularly, change is quite small usually so it can still leave you with immunity however, can also be big, so can be flu epidemics
- vulnerable groups given vaccine
- no cure
what is the most virulent strain of flu?
strain A viruses
- also classified further by proteins on their surfaces, eg. A(H1N1) and A(H3N3)
what is malaria?
- caused by protoctista Plasmodium
- spread by bites of infected Anopheles mosquitoes
- complex life cycle with two hosts - mosquitoes and people
- reproduce inside female mosquito
- female needs to take two blood meals to provide her with protein before she lays her eggs - this is where Plasmodium is passed onto people
- invades red blood cells, liver and brain
- can recur
- no vaccine and limited cures, but preventative measures can be effective
how can malaria spread be controlled?
controlling the vector (mosquitoes):
- destroyed by insecticides
- by removing standing water where they breed
- mosquito nets
- window and door screens
- long sleeved clothing
what is ring worm?
- fungal disease infecting mammals
- causes grey-white, crusty infectious, circular areas of skin
- different fungi infect different species
- not damaging but looks unsightly and may be itchy
- antifungal creams are an effective cure
