B5-Communicable Diseases Flashcards
what are pathogens
Pathogens = disease-causing microoganisms
what does communicable diseases mean
Communicable diseases = infectious diseases = these can be passed from one person to another
what does non-communicable diseases mean
Non-communicable diseases = diseases that cannot be transmitted from one person to another
what affects disease and illnesses
Diet = without the right nutrients you can get diseases like starvation, anaemia or rickets (deficiency of vitamin d - sunlight). Too much food can lead to obesity, cancers or Type 2 diabetes
Stress = Too much stress is linked with some cancers, heart disease and mental health problems
Life situations:
Part of the world you live in
Gender
financial status
ethnic group
levels of free healthcare
number of children
local sewage and rubbish disposal
what are the types of pathogens
Types of pathogens: Bacteria, Virus, Fungi (pl of fungus), Protists
how can communicable diseases be caused
Communicable diseases can be caused either directly by the pathogen, OR by toxins made by the pathogen
what is bacteria
Bacteria = unicellular organisms that are much smaller than animal and plant cells
what are viruses
Viruses are even smaller than bacteria, have regular shapes and cause disease in every living organism
how do bacteria divide
Bacteria divide by splitting into two, in a process called binary fusion
how do bacteria affect your body
Bacteria affects your body in one of two ways:
produces toxins that affect your body and make you feel ill
directly damage and destroy your cells
give an example of disease spreading through Air for animals and plants
Air - this includes droplet infection - for human diseases, you expel tiny droplets full of pathogens from your respiratory system when you cough, sneeze or talk - others then breathe these in from the air
what are ways in which disease can spread from one to another
Air, direct contact and water
give an example of disease spreading through direct contact for animals and plants
Direct contact - common in plants, when a tiny piece of infected plant material left in a field infects a new crop. In people, STDs. Some pathogens can enter through sexual contact, cuts, scratches and needle punctures that give access to blood. Animals can act as vectors of plant and animal diseases. Vector = carrier for the disease
give an example of disease spreading through water for animals and plants
Water - fungal spores in splashes of water can spread plant diseases. Humans: eating raw, undercooked or contaminated food
what can cause disease to spread more rapidly
Living in crowded conditions can cause disease to spread rapidly
how do viruses live and reproduce
Viruses take over cells - they live and reproduce in them, damaging and destroying them
what are common symptoms of communicable disease
Common symptoms of communicable diseases are: Fever, headache, rash, cough
what is a group of bacteria called
a group of bacteria is called a colony
what do you need to culture micro-organisms
to culture micoorganisms, you provide a culture medium, warmth and oxygen –> normally you use agar gel - a nutritious culture medium for bacteria
what is important to prevent when culturing bacteria
It is important to prevent contamination when culturing bacteria!!
To avoid this, all equipment, and work surfaces are sterilised
why is bacteria kept at 25degrees Celsius and not 37
Cultures have to be at 25degrees celsius –> you have to make sure the temperature is not near 37degrees so that even you culture some harmful pathogens, they won’t survive in the body
what is growth of bacteria affected by
Growth rate of bacteria is affected by: temperature, pH, available nutrients and O2 levels
what are ways to drastically prevent growth of bacteria
Ways to prevent the growth of bacteria: drastically raise or lower the temperature
what is the difference between disinfectant, antiseptic and antibiotic
- Disinfectant - kills bacteria in the environment around - NOT USED ON THE BODY
- Antiseptic - kills bacteria - safe to use ON the skin but not IN the body
- Antibiotic - kills bacteria INSIDE the body
what factors affect spread of disease
Hygiene prevents the spread of communicable diseases - washing hands, using disinfectant, separating raw meat from ready-to-eat foods, coughing and sneezing into something
Isolating infected people/plants reduces the spread of diseases
By controlling the number of vectors, the spread of disease can be reduced
what are vectors
Vectors = living organisms that carry a pathogen
why dont vaccines work on plants
Vaccines don’t work on plants as plants don’t have an immune system
what are symptoms
Symptoms is the result of the way the body reacts to the viruses damaging and destroying cells as they reproduce
what is the symptoms for measels and how do they spread
Main symptoms for the virus measles: a fever, and a red skin rash
Measles are spread via droplet infection (when someone coughs or sneezes)
what does MMR stand for
MMR vaccine = Measles, Mumps and Rubella
what does HIV stand for
HIV = Human Immunodeficiency Virus –> remember this name by remembering that HIV destroys our white blood cells, making the Human Immunodeficient
what are the symptoms for HIV
At first HIV only creates flu-like symptoms (headache, fever, sore throat), so most people won’t realise they have HIV
when does HIV become AIDS
Sometimes, it can be hidden for years, until your immune system is so weak that it can’t deal with simple infections, cancers and at this point it becomes AIDS ( when there is 200 or less white blood cells you officially have AIDS)
what does AIDS stand for
AIDS = Acquired Immuno Deficiency Syndrome
the time between HIV and AIDS is affected by?
3 points
The time between when HIV becomes AIDS is affected by:
1. nutrition
2. overall health of the person
3. access to anti-retroviral drugs
what are anti-retroviral drugs
Antiretroviral drugs = slows down the progression of HIV
how is HIV spread
3 points
HIV is spread by:
1. through sexual contact
2. blood on needles and transfusion
3. from mother to baby during birth or in breastmilk
how will the use of anti-retroviral drugs impact the patient
The regular use of antiretroviral drugs will significantly extend their time before the disease progresses to AIDS
What does TMV stand for
TMV = Tobacco Mosaic Virus
what are results of the TMV virus
Makes a distinct ‘mosaic’ pattern when destroying cells –> affects growth –> affected areas cannot photosynthesise
what do anti-biotics do
Antibiotics kill bacteria, stop them growing, and cure bacterial diseases
what does pathogen mean
Pathogen = disease causing microorganism
where can salmonella be found
Found in raw meat, poultry, eggs and egg products like mayonnaise
what are the common causes of salmonella
A common cause is eating undercooked food, or unhygienically prepared food (for example, using the same knife, or the same chopping board for both raw meet AND ready to eat food like vegetables, OR storing raw meat beside ready to eat food
what are salmonella symptoms
Symptoms = vomiting and diarrhoea, and abdominal cramps
what is a bacterial STD
Bacterial STD: Gonorrhoea
what are symptoms of Gonorrhoea
Symptoms: a thick yellow-green discharge from your the penis/vagina, and pain on urination
what can happen if it is left untreated
Untreated, it can cause long term pelvic pain, infertility and ectopic pregnancy (this is when the fertilised egg is outside the uterus (womb=uterus))
what would happen to a baby that is born to a mum with Gonorrhoea
A baby born to a mum with gonorrhoea will likely have eye infection or be blind
what are preventions of Gonorrhoea
Prevention:
Condoms and reducing the number of sexual partners will reduce the chances of getting gonorrhoea
Agrobacterium tumefaciens - This bacteria passes down a specific section of their DNA by infecting the plant cell
what type of disease is athletes foot
Athlete’s foot is a minor fungal skin disease
where are fungal diseases more common in
Fungal diseases are more common in plants
what does rose black spot affect and what does it cause
ROSE black spot is a fungal disease of ROSE leaves
Causes purple or black spots on the leaves - this is a nuisance for garden/commercial flowers
how does rose black spot affect plants
Rose black spot weakens the plant, as the affected areas can’t photosynthesise, so the plants can’t flower well –> this is is a problem because the purpose of people growing roses is for the flower
how can you prevent rose black spots
Prevent it by removing/burning affected leaves and use chemical fungicides
what does -icide mean
-icide = a chemical that kills something
what do most diseases caused by protists involve
Most diseases caused by protists usually involve vectors
what are vectors
Vectors are living organisms that carry/transport the pathogen/protist without being infected themself
what is malaria caused by
Malaria is caused by protist pathogens, which are parasites (parasites meaning live and feed on other living organisms)
how do malaria reproduce?
The malaria protist reproduces sexually in mosquitoes and asexually in humans (mosquitos are closer in size to protists, as they are smaller, so protists reproduce sexually in mosquitoes)
what is the vectors of malaria
Mosquitoes are the vectors of the disease
how do protists affect the body?
Protists are passed into the human bloodstream by the mosquito –> affect the liver and red blood cells (they kill red blood cells by bursting out of them)
what are symptoms of malaria
Causes recurrent episodes of fever and shaking (this happens when the protists burst out of the red blood cells)
define primary defence system
Primary defence = the things that stop pathogens from entering your blood/body
what does the skin act as
Your skin is a barrier between pathogens and the tissues behind it
how is infection prevented from coming into a cut
A damage/cut - it creates an opening in the skin –> platelets form a clot –> creates a scab –> forms a seal over the cut, sealing the barrier - stops you bleeding to death AND it stops pathogens getting direct entry into your body
what does skin produce to destroy pathogens?
Skin produces antimicrobial secretions to destroy pathogenic bacteria
how does skin fight pathogens
Healthy skin is covered with microorganisms –> helps keep you healthy and acts as an extra barrier for pathogens
how are pathogens stopped when breathing in
Your nose is full of hairs and produces mucus
These hairs and mucus trap particles in the air that might have pathogen or can irritate your lungs
Trachea and the bronchi also create mucus to trap pathogens in air
what are the two pipes in your throat and what are in these tubes that help fight pathogens
There are two pipes in your throat
Trachea = wind pipe
Oesophagus = food pipe
These tubes are lined with cilia –> tiny hair-like structures –> beat to waft mucus up to the back of the throat
how does the stomach fight pathogens
Stomach produces strong hydrochloric acid –> this strong acid destroys any microorganisms in the mucus as well as any microorganisms in the food and drink that you swallow
what is the secondary defence
Secondary defence: White Blood cells
what are the 2 types of white blood cells
Two types of white blood cells are phagocytes and lymphocytes
what do phago-cytes do
Phagocytes - (phago=eating) - they engulf the pathogens, ingest, digest and destroy them
what do lymphocytes do?
Lymphocytes:
1. Produce antibodies - these target particular bacteria or viruses, destroying them. A unique antibody is needed for each specific pathogen (which each has its own unique antigen on the pathogen’s surface). The antibodies produced are complementary to the antigens on these pathogens. Once an antibody is made, the next time the pathogen enters the body, the correct antibody can be made really quickly, to destroy the pathogens quickly before they can do enough harm to produce symptoms
2. Produce antitoxins - some produce antitoxins which neutralise the toxins released from pathogens
why does mucus look green
Dead WBCs, dead bacteria and dead viruses are removed in the mucus, making it look green
how can insect/pests destroy plants
Insect pests can destroy a plant directly, or indirectly using vectors
what do aphids feed from
Aphids feed on the sugary liquid running in the phloem, using their long, sharp mouthparts
what do aphids also act as?
Aphids also act as vectors transferring bacteria, viruses, fungi
how can aphids be destroyed
The aphids can be destroyed using chemical pesticide, or (in enclosed species) biological pest control –> release aphid-eating insects (for example ladybirds). You can also destroy the aphid larvae (eggs), controlling the population
how do nematode and insect larvae affect the plant (underground)
Tiny nematode worms and insect larvae that live in the soil feed on plants roots –> damages them - plants can’t absorb water and mineral ions
how does nitrate deficiency affect the plant
With nitrate deficiency, the plant has stunted growth –> nitrogen and glucose react to make amino acids (which form proteins, which is used for growth) - (think of it like this- to grow your muscles, you need to eat protein, same way for the plant to grow, it needs protein, which it makes from nitrates)
what are some barriers in cell wall
The cellulose wall strengthens the plant cells and act as a barrier against pathogens –> aphids create an opening in this
Waxy cuticle is another barrier –> stomata is the only way into the leaf for pathogens
how does bark on trees and dead cell protect plants
Bark on trees and dead cells on stems of plants protect –> when they fall, the pathogens fall with them
why do plants produce anti-bacterial chemicals
Plants produce antibacterial chemicals –> prevents invading pathogens and bacterial diseases –> pines have antibacterial properties
what are defences against herbivores
3 points
Defences against herbivores:
1. Poisons –> animals quickly learn to avoid plants that make them feel unwell
2. Thorns –> makes it painful for bigger organisms, but it doesn’t deter insects
3. Hairy stems/leaves - deters herbivores from feeding, and deters insets from laying their eggs on them ( for example nettles)
what is mimicry in plant defence
Mimicry = some plants droop to mimic unhealthy plants + prevents bigger herbivores from eating them. Some mimic butterfly eggs –> prevents butterflies to lay their eggs to avoid competition with caterpillars
