CHAP 8 INFECTIOUS DISEASE IN HUMANS Flashcards
what is a disease?
a condition that causes the body to function less effectively
what are signs of a disease?
can be observed or measured
[ rashes, fever, coughing & vomiting ]
what are symptoms of a disease?
can be described or felt by the patient
[ nausea, headache & fatigue ]
what are pathogens?
pathogens are disease causing organisms such as virus & bacteria
what are some examples of infectious disease?
• HIV
• influenza
• covid 19
• pneumococcal disease
what causes non-infectious diseases?
• air pollution
• malnutrition
• lifestyle choices
• inherited diseases - type 2 diabetes
what are examples of non-infectious disease?
• sickle anaemia
• coronary heart disease - caused by excessive consumption of polyunsaturated fats and trans fats
• atherosclerosis- caused by excessive cigarette smoking
• liver cirrhosis- caused by excessive alcohol consumption
how many ways can infectious disease spread?
3
in what ways does infectious disease spread?
• through tiny droplets in the air
• through direct contact
• by contaminated food & water
how does tiny droplets in the air spread infectious disease?
cough/sneeze->numerous tiny respiratory droplets are expelled->droplets might contain pathogens->anyone within close range (1m) may breathe in these droplets->be infected
how does infectious disease spread by DIRECT CONTACT?
• sexually transmitted disease (STIs) & human immunodeficiency virus (HIV) - can be transmitted when exchanging of bodily fluids during sexual intercourse
• hepatitis B & syphilis can be transmitted through breastfeeding ( mother & baby )
• can be spread through blood - when BLOOD of infected comes in contact with the MUCOUS MEMBRANES ( eg. membrane lining the eye,nose and mouth ) OR BLOOD STREAM of uninfected
how to prevent the spread of water-borne & food-borne diseases? [4]
- practice hygienic food preparation & storage
- practice good personal hygiene
- ensure proper sewage treatment
- maintain clean water supply
what is an INFLUENZA & what causes it?
a disease that attacks the respiratory system
influenza virus
how is INFLUENZA TRANSMITTED & what are some methods to prevent transmission? [3]
- through droplets in air / someone touches eye, mouth or nose after touching an object that is contaminated by virus
a) get influenza vaccination
b) cover nose & mouth when cough/ sneeze with tissue & properly dispose used tissue
c) avoid close contact with sick people
what is PNEUMOCOCCAL DISEASE & what causes it?
- a disease that attacks different parts of the body such as spinal cords , brain, lungs & blood
- pneumococcal bacteria -> streptococcus pneumoniae
what are signs & symptoms of pneumococcal disease?
fever , cough , rapid breathing , headache , vomiting & chest pain
what are methods to reduce PNEUMOCOCCAL DISEASE transmissions?
a) pneumococcal vaccine
b) take antibiotics prescribed by doctors
what are vaccines?
- an agent that resembles pathogens & prevents infectious disease by stimulating WBC to quickly produce antibodies when pathogens invade
how does vaccines work?
vaccine ( contains agent that reassembles a pathogen) -> enters the body-> WBC binds to agent -> WBC stimulated to divide -> WBC produce antibodies -> antibodies destroy the pathogen in vaccine
antibodies are _______
specific - binds to certain virus / antigen
what are antibiotics used for?
-drugs used to treat bacterial infections -> made by microorganisms & used to kill/ inhibit the growth of bacteria
why are antibiotics used to kill bacteria? [4]
a) weakening the bacteria cell wall -> allowing water to enter the cell by osmosis -> cause cell to swell -> burst
b) inhibit some enzymes -> inhibit growth of bacteria
c) preventing ribosomes from making proteins & enzymes -> killing bacteria
d) breaking up cell membrane
why are antibiotics INEFFECTIVE against viruses? [3]
viruses do not have:
- cell wall
- cell membrane
- ribosomes
how can a person recover from a viral infection? [2]
- requires rest -> body will recover with time
- antivirals -> medications that help body fight off disease causing viruses.
how does misuse of antibiotics cause ANTIBIOTIC RESISTANCE?
a population of bacteria -> some bacteria are more sensitive and some less sensitive to antibiotics -> initial doses of antibiotics -> bacterial cells that are more sensitive killed -> bacteria less sensitive not easily killed & may survive
a) IF prescribed course of antibiotics completed -> higher chance that all bacterial cells are killed
b) IF prescribed course of antibiotics NOT completed -> less sensitive bacterial cells that survived will multiply & increase in numbers -> overtime generations of bacterial cells -> increasingly less sensitive to antibiotics -> population of cells becomes resistant to antibiotic -> antibiotic unable to kill bacteria-> other types of antibiotics required to treat bacterial infections.
how can antibiotic resistance be REDUCED ? [3]
- not misuse / overuse antibiotics
- complete full course of antibiotics prescribed by doctor-> all bacteria killed
- using antibiotics ONLY when necessary
