4.1)Communicable Diseases Flashcards
what is a communicable disease?
disease that can be passed from person to person
what causes communicable diseases?
pathogens
what are the types pathogens?
bacteria
fungi
protists
virus
what is a vector?
something that carries pathogens from organism to organism
how do bacteria cause disease?
reproduce rapidly inside the host cell—>release waste products/toxins that are toxic to host—>disease
where do bacteria live in plants nd why?
vascular tissue (phloem + xylem where nutrients are transported)
able to gain the nutrients from the plant
what kingdom does bacteria belong to?
prokaryotes
what are viruses?
non-living infectious agents
50x smaller than average bacterium
how do viruses cause disease?
invade host cell
takes over hosts genetics to produce more viruses
virus adapts to host + evolves
=
disease
what is bacteriophage nd used for what?
virus that infects nd replicates inside of bacteria
used to identify nd treat diseases
what is fungi?
(pathogen)
multicellular eukaryotes
heterophic (intake food from surroundings)
saprophytic (lives off dead material) & parasitic (lives off host)
how can fungi live of skin of animals?
hyphae of fungi form a mycelium that grow under skin surface = sends ot specialised reproductive hyphae that grow to surface of skin = releases spores
what molecules do fungi release?
cellulase (digestive enzyme) to digest cellulose cell wall of plant = infiltrates vascular system = takes nutrients from phloem nd xylem
what are protists?
unicellular/multicellular
eukaryotes
often need vector to transfer
what are the vectors of protista?
animal (e.g mosquito insect)
OR
pollutes water
what is the malarial parasite nd what does it feed off?
plasmodium
feeds on haemoglobin inside red blood cells
diff between the way that virus nd protists cause disease?
virus = takes over hosts DNA nd uses host to make new virus
protists = DO NOT take over hosts DNA nd jst uses it
animal diseases caused by bacteria?
TB
Bacterial meningitis
plant disease caused by bacterium?
Ring rot
animal diseases caused by virus?
HIV/AIDS
Influenza
plant disease caused by virus?
tobacco mosaic virus (TBV)
plant disease caused by fungi?
Black sigatoka (in banana)
animal diseases caused by fungi?
ringworm (cattle)
athlete’s foot (human)
animal disease caused by protoctista?
malaria
plant disease caused by protoctista?
blight (tomatoes nd potatoes)
what does HIV virus contain nd why?
RNA & Reverse Transcriptase Enzyme (RTE)
RTE coverts RNA—>DNA so that the DNA can be replicated
What are the 2 types of transmission nd which is more common?
Direct - more common
Indirect
What is the means of transmission of:
HIV
Bacterial meningitis
STI’s
Ringworm
Athlete’s foot
&
How to reduce transmission route?
Direct physical contact w someone’s bodily fluids 👥
-wash hands regularly 🖐️
-sterilise equipment ✂︎
-sterilise surfaces 🧽
-use condoms
What is the means of transmission of:
Rabies
Septicemia (blood infection)
&
How to reduce transmission route?
Breaks in skin (e.g Animal bites, wounds/cuts, needle puncture)
-cleaning & covering wounds🩹
what is the means of transmission of:
Dysentery
Cholera
Diarrhoeal diseases
&
How to reduce means of transmission?
(faecal-oral route) Ingesting contaminated food or transferring pathogens to mouth (e.g. eating w unwashed hands after using toilet)
-treating waste/drinking water 💧
-washing food 🫑
-cooking food thoroughly 🥩
what is the means of transmission of:
Anthrax (caused by bacteria found in soil)
Tetanus
&
How to reduce means of transmission?
Transmission by SPORES (resistant stage of pathogen) carried in air(wind), residue on surfaces or in soil
-use mask 😷
-wash skin after contact w soil 🧼
what is the means of transmission of:
Herpes
Athlete’s foot
&
How to reduce means of transmission?
Inanimate objects (e.g. bed sheets, surfaces, socks, cosmetics, brushes)
-wash clothes/bedding regularly 🧺
-clean surfaces 🧼
What is the means of transmission of:
Influenza
Tuberculosis
&
How to reduce means of transmission?
Pathogen carried in water droplets through air (e.g talking, coughing, sneezing)
-cover mouth when sneezing/coughing
-dispose of tissues correctly🧻
What is the means of transmission of:
Bubonic plague
Malaria
Rabies
Diarrhoeal diseases
&
How to reduce means of transmission?
Vectors (e.g. rat fleas, mosquito, raccoons, dogs, water) that transmit the pathogen from one organism to another
-wash animal🦝🛁
-insect repellant🦗
-ensure water is clean💧
What causes someone to be infected w malaria?
Plasmodium parasite transmitted by female Anopheles mosquito vector🦟🦟🦟🦟🦟🦟🦟🦟🦟🦟🦟🦟🦟🦟🦟🦟🦟🦟 🦟🦟🦟 🦟🦟🦟 🩸
What are the ways to control spread of malaria?
-reduce stagnant water 🏊(mosquitos favour stagnant water & reproduce here)
-malarial tablets (6 weeks before going to 🦟 environment)
-mosquito nets
-insect repellant🦗
Describe cycle of transmission of malaria
Female Anopheles 🦟 sucks blood w Plasmodium gamete
↓
Plasmodium gamete migrate to salivary glands of 🦟
↓
🦟 bites uninfected person 👤
↓
plasmodium parasite moves to liver of person
↓
plasmodium parasite moves to blood🩸
=
👤person is infected
what are some factors affecting pathogen transmissions in animals?
OVERCROWDING (close proximity = easy spread)
POOR VENTILATION (no dispersion of airbourne particles that carry pathogens)
POOR HEALTH (weak immune system unable to fight pathogens)
MIGRATION FROM INFECTED AREAS (higher risk of transmission)
CULTURE/INFRASTRUCTURE (traditional medicinal practices/way food is cooked may increase risk of transmission)
POOR WASTE DISPOSAL (build up of pathogens creating unsanitary conditions)
SOCIOECONOMIC FACTORS (lack of trained health workers/insufficient public warning during outbreak of disease=less prepared=increase outbreak/rate of transmissions)
what are examples of direct transmission of plant pathogens?
direct contact of healthy plant w infected plant
RINGROT
TOBACCO MOSAIC VIRUS
TOMATO/POTATO BLIGHT
BLACK SIGATOKA
what are the means of indirect transmission in plants?
SOIL CONTAMINATION (pathogens in soil enetr via roots when roots damaged by replanting, burrowing animals, uprooting)
SPORES (carried in wind)
LEAVES (leaves carrying pathogens are shed and carried to soil where it can grow/infect another plant)
FRUITS/SEEDS (pathogens enter fruit/seed which are distributed within the plant=infect offspring)
VECTORS (animals, humans, water, wind)
what are other factors that affect pathogen transmission in plants?
PLANTING VARIETIES OF CROPS THAT R SUSPECTIBLE TO DISEASE
OVERCROWDING
POOR MINERAL NUTRITION
DAMP, WARM CONDITIONS
CLIMATE CHANGE
what are the means of reducing plant transmissions?
1)leave room between plants so pathogens can’t spread easily
2)clear fields thoroughly to remove all traces of plants from the soil
3)rotate crops so spores/bacteria will dies as they don’t have access to host plant
4)strict hygiene practices to prevent bacteria coming into contact w plants
5)control insects - that could act as vectors that transport pathogens
why do people suffer from food poisoning when travelling to tropical regions?
-pathogens thrive in damper/warmer conditions
-there are diff pathogens that we don’t have immunity to
-diff countries cook food in diff ways
why do diseases such as malaria nd dutch elm disease not ham the vector that is involved in transmitting the pathogen?
the specific cell surface receptors are absent in the vector
why do some large trees die years after a major storm?
strong winds may cause uprooting which exposes roots and allows pathogen-infected soil to penetrate nd infect the tree
why can’t pathogens living in the soil infect plants unless the roots are damaged/exposed?
outer tissues of roots act as physical barriers nd some pathogens mau not have the enzymes to penetrate nd break through the cell wall