12.2 Animal and Plant Diseases Flashcards
What are the 4 common plant diseases?
Ring rot
Potato blight
Tobacco Mosaic Virus
Black Sigatoka
What is ring rot?
A bacterial disease of potatoes, tomatoes and aubergines, caused by Gram-positive bacteria.
What damage does ring rot cause?
Ring rot damages leaves, tubers and fruit.
Ring rot can destroy 80% of a field and there’s no cure.
Once ring rot infects a field, how long do you have to wait to grow potatoes again in the same field.
2 years
What is Tobacco Mosaic Virus (TMV)?
A virus that infects tobacco plants and 150 species of plants, including tomatoes and cucumbers.
What damage does TMV cause?
TMV damages leaves, flowers and fruit
TMV stunts plant growth and reduces yield, leading to almost complete crop loss
How can the spread of TMV be prevented?
Resistant strains are available, but once infected, there’s no cure
What is potato blight (+ other blights) caused by?
Fungus-like protoctist oomyecete.
What damage does potato blight cause?
The hyphae penetrate host cells, destroying leaves, tubers and fruit, causing millions of £ of crop damage annually
How can you reduce the risk of potato blight?
Resistant strains are available, but there’s no cure.
Careful management and chemical treatment can reduce the risk of infection
What is black sigatoka?
A banana disease caused by fungus
What damage does black sigatoka cause?
Attacks and destroys leaves.
The hyphae penetrate and digest cells, turning leaves black.
If infection occurs, up to 50% loss can occur
How can the spread of black sigatoka be prevented?
Resistant strains are being developed.
Good husbandry and fungicide treatment can control the spread, but there’s no cure.
What is a fungicide?
A chemical that kills fungi
What are the 4 common animal diseases?
Tuberculosis (TB)
Bacterial Meningitis
HIV/AIDS
Influenza (flu)
What is tuberculosis?
A bacterial disease of humans, pigs, cows, badgers and deers, commonly caused by bacterium tuberculosis
What damage does TB cause?
- Damages and destroys lung tissues
* Surpresses immune system, so the body is more vulnerable to other diseases
How has a rise in HIV allowed TB to spread?
People with HIV are more likely to be infected by TB
How can the spread of TB be controlled?
TB can be cured with antibiotics
TB is preventable by improving living standards and through vaccination
What is bacterial meningitis?
A bacterial infection of the brain’s meninges (the protective layers of the brain’s surface)
How does bacterial meningitis cause damage?
Bacterial meningitis can spread to the rest of the body, causing septicemia(blood poisoning) and rapid death
What age group does bacterial meningitis commonly affect?
Young children.
Teenagers 15-19
What symptom of septicemia means immediate medical treatment is needed?
When a red rash is pressed and doesn’t ‘disappear’
What % of people infected with septicemia die?
10%
What % of people who have recovered from septicemia will have permanent damage?
25%
How can the spread of bacterial meningitis be reduced?
Antibiotics can cure the disease in early stages.
Vaccines protect against some forms of bacterial meningitis
What is HIV/AIDS?
AIDS is a condition, HIV is a virus.
Acquired Immunodeficiency Syndrome (AIDS), caused by HIV (Human immunodeficiency Syndrome), targets T helper cells in the body’s immune system.
How does HIV/AIDS cause damage?
After targeting the host’s immune system, AIDS gradually destroys the immune system, leaving the host more vulnerable to other diseases e.g. TB + pneumonia + some types of cancers
What group of organisms does HIV affect?
Humans and other primates
Describe what HIV is, relating to its structure.
Retrovirus with RNA as its genetic material.
How does HIV work?
- Contains enzyme reverse transcriptase, which transcribes HIV’s RNA to a single strand of DNA to produce a single strand of DNA in the host cell.
- This DNA interacts with genetic material of the host cell.
How is HIV spread?
- Passed from one person to another through bodily fluids, commonly through unprotected sex, shared needles and contaminated blood products.
- HIV can also pass from mother to baby during pregnancy, birth or breastfeeding.
What is available to reduce the spread of HIV?
There is no cure or vaccine, but anti-retroviral drugs slow the progress of the disease.
What traditional practice spreads HIV? Why does this practice spread HIV?
Female genital mutilation - The same equipment used several times can spread infection and women with FGM are more likely to get HIV through intercourse.
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What is influenza (flu)?
A viral infection of the ciliated epithelial cells in the gas exchange system.
What damage does the flu cause?
Kills ciliated epithelial cells, leaving the airways open to secondary infection.
In which people is influenza most likely to be fatal?
Young children, old people and people with chronic illnesses
What causes most of the deaths after a person is infected with influenza?
Secondary bacterial infections e.g. pneumonia, on top of the original viral infection
What organisms does the flue infect?
Mammals, i.e. human and pigs and birds including chickens
What are the 3 main strains of influenza?
A, B and C
Which of the influenza strains are the most severe?
Strain A
How are strain A influenza viruses classified?
By the proteins on their surface, e.g. A(H1N1) and A(H3N3)
How often do flu viruses mutate? How is the extent of this mutation good for us?
Regularly - however, the changes are small, so having flu one year leaves you with immunity for the next
Why do flu pandemics occasionally occur?
Rarely, there is a major change in influenza’s surface antigens. This means there are no antibodies available to quickly eliminate it.
How can the spread of flu be limited?
Vulnerable groups of people are given annual vaccines against changing strains.
There is no cure.
What is malaria caused by?
The protoctista plasmodium.
What is malaria spread by?
Infected female anopheles mosquitoes.
What are the 2 hosts which are a part of plasmodium’s life cycle?
People and mosquitoes
What is the life cycle of plasmodium?
Reproduce inside female mosquito.
Female mosquito requires 2 blood meals before laying eggs - this is when plasmodium is passed on to people.
What does the plasmodium do?
Plasmodium invades erythrocytes, the liver and the brain.
What is the consequence of malaria recurring?
Makes the host weak and more vulnerable to other infections
How can malaria be treated?
No vaccine and limited cure.
How can the spread of malaria be limited?
Through preventative measures - these are very effective.
The key is to control the vector.
Explain what the preventative measures to malaria are.
Anopheles mosquitoes can be eliminated through:
Insecticides
Removing standing water, which they need to reproduce
Mosquito nets, window+door screens and long sleeved clothing prevent mosquitoes biting.
What is ring worm?
A fungal disease
What organisms does ring worm affect?
Mammals i.e. cattle, dogs, humans
Is ring worm the same in all infected organisms?
No - different fungi infect different species
What are the symptoms of ring worm in cattle?
Grey-white, crusty, infectious, circular areas on skin.
Not damaging but may be itchy.
How do you cure ring worm in cattle?
By using antifungal creams
What is athlete’s foot?
A human fungal disease caused by Tinia pedia - human form of ring worm
What does athlete’s do?
Grows on and digests the warm, moist skin between toes
What damage does athlete’s foot do?
Athlete’s foot causes cracking and scaling, which is itchy and sore
How can athlete’s foot be treated?
Through antifungal cream
