B5 communicable diseases Flashcards
(69 cards)
1
Q
What is the difference between communicable diseases and non-communicable diseases?
A
Communicable diseases are caused by pathogens that can be passed from one person to another
Non-communicable diseases cannot be transmitted from one person to another
2
Q
What are some factors that can affect health?
A
diet
-lack of nutrients, food, ED, obesity
stress
-too much, linked to range of health problems (heart disease, cancer)
life situations
-area, gender, financial status, ethnic group, level of free health care
(communicable diseases- diarrhoea, malaria)
(non communicable diseases- heart disease, cancer)
illness
3
Q
What is a communicable disease?
A
it is an infection that is caused by pathogens such as bacteria and viruses
can be passed from one person to the other (infectious)
(tuberculosis, flu)
4
Q
What is a non-communicable disease?
A
cannot be transmitted from one person to the other
(heart disease, arthritis)
5
Q
What illnesses can viruses lead to?
A
can trigger changes leading to cancers
HPV (human papilloma virus-> cervical cancer)
6
Q
What can defects in the immune system be the result of?
A
-genetic makeup
-poor nutrition
-infection (HIV/AIDS)
7
Q
What can defects in the immune system lead to?
A
higher risk of suffering from communicable diseases
8
Q
What are immune reactions caused by?
A
pathogens
ie reaction to common cold
9
Q
What can immune reactions lead to?
A
trigger allergies to environmental factors
cause skin rashes, hives, asthma
10
Q
How are physical and mental health linked?
A
severe physical ill health can lead to mental illnesses (depression etc)
11
Q
What does malnutrition lead to?
A
health issues
-deficiency diseases
-weakened immune system
-obesity
-cardiovascular diseases
-type 2 diabetes
-cancer
12
Q
What are microorganisms that cause disease called?
A
Pathogens
infect animals and plants, causing disease
13
Q
What are some examples of pathogens?
A
bacteria, viruses, protists, fungi
14
Q
What are communicable diseases caused by?
A
- directly by a pathogen
- by a toxin made from a pathogen
15
Q
How are communicable diseases passed?
A
from one infected individual to another uninfected individual
16
Q
What are some examples of communicable diseases?
A
-common cold, tonsillitis
-tetanus, influenza, HIV/AIDS
17
Q
What is an example of a communicable disease passing between different species?
A
- infected dogs can pass rabies onto people
- tuberculosis can pass from badgers to cows, cows to people
18
Q
What are the most common pathogens in plants?
A
viruses and fungi
19
Q
What are bacteria?
A
single celled living organisms
smaller than animal and plant cells
living (can survive outside a host)
can be treated by antibiotics
20
Q
What are some uses for bacteria?
A
- make food (yogurt, cheese)
- treat sewage
- make medicine
- decomposers in the environment and body
21
Q
What are the most common pathogens in humans?
A
Bacteria and Viruses
22
Q
What is a virus?
A
even smaller than bacteria
non living
cannot be treated by antibiotics
23
Q
How do bacteria cause disease inside the body?
A
-divide rapidly by splitting in 2 (Binary fission)
-may produce toxins that affect the body (cause symptoms)
- sometimes directly damaging the cell
24
Q
How do bacteria divide/reproduce?
A
binary fission
25
How does a virus cause disease inside the body?
- take over the cells in the body
- live and reproduce inside the cell
- damage and destroy cells
26
What are common symptoms of disease?
- high temperature
- headaches
- rashes
caused by the body responding to the pathogens toxins and cell damage
27
How do pathogens spread?
Through the air
-droplet infection, human expel tiny droplets with pathogens from breathing system when coughing, sneezing or talking. Others breathe in the droplets
-flu, influenza, common cold
Direct contact
- common in plants
-infected leaf left in field can infect entire new crop
-humans, STI (syphilis, chlamydia), direct contact of skin
-HIV/AIDS, hepatitis enter through direct sexual contact, bodily fluids (cuts, scratches, needle punctures)
-animals can be a vector of plant and animal diseases (carrying pathogen between infected and uninfected individuals)
By water
-plants. fungal spores carried in splashes of water
-humans, eating raw, uncooked, contaminated food. Drinking water containing sewage
(salmonella, cholera)
- enters through digestive system
Lifestyle factors
- crowded living conditions, no sewage system etc
28
What is a vector?
a carrier of a pathogen between infected and uninfected individuals, can be between different species
can carry plant and animal pathogens
(ie mosquito)
29
What is a culture medium?
a liquid or gel containing nutrients
30
What are conditions microorganisms need to grow?
- warmth
- oxygen
- culture medium (carbohydrate, minerals, nitrogen source, chemicals)
31
How can cultures become contaminated?
skin, air. soil, water around
32
What is a mutation?
a change in the DNA
in pathogens it can create a new and dangerous pathogen
33
Why is the maximum temperature for culture incubation in schools 25 degrees C?
- 37 degrees is human body temperature
- high risk of growing dangerous pathogens
- low temp, reduce risk of growing harmful bacteria
34
Why are industries allowed to incubate cultures at 37 degrees C?
- enables microorganisms to grow quicker
- can be used for use faster
35
What is the growth rate of bacteria affected by?
- temperature
- available nutrients
- oxygen levels
- pH
36
How can you prevent the growth of bacteria?
-raise or lower the temperature
- chemicals to stop them growing/killing them (disinfectant for environment around, antiseptic for human skin, antibiotics inside the body)
37
Ignaz Semmelwies + what did he discover?
He was a doctor mid 1850's
-Many women were died from childbed fever a few days after birth, no cause
-he noticed medical students didn't wash their hands between dissecting corpses to delivering babies. He thought they could be carrying disease from the bodies to the patients
- he insisted medical students wash their hands before delivering babies
38
Louis Pasteur + Joseph Lister -> what did they discover?
Mid to late 19th century
Louis Pasteur: showed microorganisms caused disease, developed vaccines (anthrax, rabies)
Joseph Lister: used antiseptic chemicals in operating theatres to destroy pathogens before causing any infection
39
How can hygiene prevent the spread of communicable diseases?
- hand washing (after toilet, before cooking, after animal contact etc)
- using disinfectant (kitchen surfaces, toilets, reduce number of pathogens)
- keeping raw meat away from food eaten uncooked (prevent pathogen spread)
- coughing/sneezing into handkerchief, tissue, hands (then wash hands)
- maintaining hygiene of people and agricultural machinery (prevent spread of plant disease)
40
How can isolating infected individuals prevent the spread of communicable diseases?
-less amounts of healthy people come into contact with them
-less likely pathogens pass on
- same for plants
- only works for small, movable plants
41
How can destroying or controlling vectors prevent the spread of communicable diseases?
spread of diseases can be prevented or reduced
- houseflies carry human disease
- mosquitos carry a range of disease (malaria, dengue fever)
42
How do vaccination work to prevent the spread of communicable diseases?
- doctors introduce a small amount of dead or inactive form of a specific pathogen to the body
- prepares the immune system for the live pathogen. If there becomes contact with live pathogen, body won't be ill
- success protecting large numbers of humans and animals
- cannot protect plants, no immune system
43
What is Measles and how is it spread?
- fever, red rash
- spreads through droplet infection
- can cause blindness, brain damage, death
- no treatment, if infected then person must isolate
-rare in the UK
44
What is HIV/AIDS?
- HIV leads to AIDS
- HIV: mild, flu like illness, attacks immune cells. remains inside immune system until system is so badly damaged it can't deal with other infections, or cancers.
- Then it has become AIDS
onset of AIDS depends on
- level of nutrition
- overall health
- access to antiretroviral drugs
45
How is HIV spread?
- direct sexual contact, exchange of bodily fluids (ie blood, drug users share needle, unscreened blood used for transfusion)
- passed from mother to child from breast milk
no cure, spread can be prevented
-use condoms
- not sharing needles
- screening blood
- HIV positive mothers bottle feeding children
46
What is TMV?
- widespread plant pathogen affecting over 150 species of plants (ie tomatoes, tobacco plants)
- causing distinct mosaic patterns on leaves, virus destroys plant cells
- affects the growth of the plant, affected areas don't photosynthesise, reducing crop yield
47
How is TMV spread?
- by contact between diseased plants and healthy plants
- insects can act as vectors
- virus can remain infection in soil for about 50 years
- no treatment, farmers now grow TMV restraint-strains, also good field hygiene and good pest control prevents spread.
48
What are Salmonella?
- bacteria that live in the guts of many different animals.
- found in raw meat, poultry, eggs and egg products (mayonnaise)
- can cause salmonella food poisoning if ingested
- causes of infection: eating undercooked food, eating food prepped in unhygienic conditions
49
Salmonella + symptoms?
symptoms develop within 8-72 hours
- abdominal cramps, vomiting, diarrhoea
- caused by secreted toxins
- can be fatal in young children and elderly
- more serious in countries with malnutrition
50
What are ways of preventing Salmonella?
- poultry are vaccinated against Salmonella in the UK
- keep raw chicken away from food eaten raw/uncooked
- avoid washing raw chicken
- wash hands and surfaces thoroughly
- cook chicken thoroughly
51
What is Gonorrhoea?
-STD
- spread by unprotected sexual contact with infected person
- early stages have symptoms, then becomes symptomless
- early symptoms: thick yellow/green discharge from the vagina or penis, pain on urination
- untreated, can cause long term pelvic pain, infertility, ectopic pregnancies
- bacterial, can be treated with antibiotics, however their are antibiotic resistant strains
- all sexual partners of infected individual should be treated to prevent further spread
- prevent spread by using barrier method (condom), reduce number of sexual partners
52
What are examples of bacterial diseases in plants?
-rose black spot
-usually found in tropical and sub tropical regions
Agrobacterium tumefaciens- causes crown galls (mass of unspecialised cells between the root and the shoot of growing plants)
-insert plasmids into plant cells, cause mass to grow
-scientists can make use of this: manipulate bacteria so they carry desirable genes to infect plant cells with.
53
What are fungal diseases + examples?
Athletes foot- fungal skin condition
- fungal diseases can be fatal when attack the lungs or brains or ill people
- can develop damaged heart valves
- antifungal drugs, but hard to treat deep tissue infections
Plants
- common, huge crop areas are lost yearly
- stem rusts, rotting diseases
54
What is Rose black spot?
fungal disease of rose leaves
- causes purple/black spots on leaves
- bad for gardens or commercial flower growers
- leaves often turn yellow, drop early, reduces photosynthesising area, plant doesn't flower well
- spores carried by wind, spread by rain drops splashing from leaf to leaf.
- stay dormant over winter on stems and dead leaves
- can prevent by burning or removing dead leaves, chemical fungicides
- specially bred roses resistant to black spot, disease still can't be prevented or cured
55
What are protists?
a type of single celled organisms
- cause range of diseases, relatively rare pathogens
- carried diseases often serious and damaging
-usually involve a vector (mosquitos etc) to transfer to host (ie malaria)
56
What is Malaria?
- disease caused by protist pathogens, parasites (live and feed on other living organisms)
- lifecycle-> time in human body and time in female mosquito body
- reproduce sexually in mosquito but asexually in human body
- mosquito feeds 2 meals of human blood before laying eggs, protist passed into bloodstream
- protist travels human body through bloodstream
- protists burst out of blood cells: causes human body a fever and shaking
- can be fatal or weakening
57
How can Malaria be treated?
- combination of drugs (not always available in countries with malaria problems)
- Protists can become resistant
- using insecticide-impregnated mosquito nets (prevent mosquitos biting humans
- use insecticide to kill mosquitos in home, office etc
- remove standing water, spray water with insecticide to kill larvae (remove breeding ground)
- antimalarial drugs (travellers), kills parasites if in blood.
58
What are the skin defences to pathogens?
- barrier. prevents bacteria and viruses reaching tissue beneath. Cuts break barrier, restored by body by platelets to clot the cut and scab. Forms a seal over the cut, stops pathogens entering
- antimicrobial secretions to destroy pathogenic bacteria
- healthy skin is covered with microorganisms, help keep healthy, act as an extra barrier to pathogens
59
What are respiratory and digestive system defences to pathogens?
- nose hairs, produce mucus. Hair + mucus trap air particles that may contain pathogens or irritate the lungs. (working in pollution, snot becomes black, proves defence works)
-Trachea and Bronchi also secrete mucus, trap air pathogens. Cilia line them, they beat to waft mucus up to back of throat to be swallowed
- stomach produces acid, destroys microorganisms in swallowed mucus, also any other ingested.
60
What are immune system defences against pathogens?
- second line of defence: white blood cells
WBC
-Ingest microorganisms: ingest, digest and destroy pathogens so they can't make you ill
-Produce antibodies: target particular bacteria/viruses + destroy them. Unique antibody to each pathogen. If made once, can be quickly made again if repeatedly infected, stopping getting ill twice.
-Producing antitoxins: counteract the toxins produced by the pathogens
61
What are examples of plant pathogens?
Aphids
- sharp mouthparts, penetrate phloem vessels so they can feed on sugar rich phloem sap
- attack in huge numbers, depriving plant cells of photosynthesis products
- vector (transfer virus, bacteria and fungi on their mouthparts)
Worms and insect larvae
- live in the soil
- feed in or on plant roots
- cannot absorb water or mineral ions effectively (damaged)
- plant fails to grow/thrive
62
How can aphids be destroyed?
-chemical pesticides
- biological pest control (enclosed space ie greenhouse)
- release aphid eating insect (ie ladybug + their larvae) to control population, doesn't impact crop success
-
63
How does mineral deficiency lead to non communicable diseases in plants?
- Plants take magnesium ions form soil to make chlorophyll needed for photosynthesis.
- If level of ions in soil is low, plant cannot make enough chlorophyll
- Leaves become yellow, growth slows due to lack of photosynthesis
CALLED CHLOROSIS
- level of ions can be replaced with soil fertilisers, but if not replaced then plant will eventually die
64
What are symptoms of plant disease?
- stunted growth (mineral deficiency)
- spots on leaves (black rose spot)
- areas of decay or rotting (black rose spot, potato blights)
- growths (crown galls caused by bacterial infection)
- malformed stems and leaves (due to aphid infestation etc)
- discolouration (chlorosis, tmv)
- presence of visible pests (aphids, caterpillars etc)
65
How can disease in garden plants be identified?
by comparing symptoms in living plant with disease description in gardening manual/online
66
How can disease be identified in crop plants or forest trees?
- experts visit area to observe natural environment
- test samples of diseased material in lab, to identify pathogen (DNA analysis etc)
67
What are physical barriers in plants against pathogens?
- cellulose wall strengthens plant cells, also resist invasion of microorganisms (aphids break barrier, give pathogens way into cells)
- Tough waxy cuticle on leaf surface, acts as barrier to pathogen entryway. Only access at stomata
- Bark on trees, layer of dead cells on outside of stems, hard for pathogens to penetrate. When cells are shed, pathogens fall too
- Leaf fall, deciduous trees lose leaves in autumn, any leaf infection fall off tree with leaves.
68
What are chemical barriers in plants against pathogens?
- produce antibacterial chemicals, protecting pathogen invasion
- plant uses as antibiotics (mint, witch hazel= mild antiseptics in cosmetics)
69
How do plants defend themselves against herbivores?
- poison deters herbivores (foxgloves, deadly nightshade)
- thorns make it unpleasant, painful to eat the plant (brambles, cacti), may not deter insects
- hairy stems and leaves deter eating, laying eggs. Can combine with poison (nettles)
-drooping or curling when touched (frightening animals)
- Mimicry, plants droop to mimic unhealthy plants. Can mimic butterfly eggs to avoid others laying on them
