bio chap 8 - infectious diseases in humans Flashcards
What is a disease?
A condition that forces the body to function less effectively
What is a sign of a disease? Name examples
Observed or measured
Rashes, fever, vomiting coughing
What is a symptom of a disease?
Described or felt by the patient
Headaches, fatigue, nausea
What are the characteristics of an infectious disease? Name some examples
Spread from one person to another
Caused by pathogens
Influenza, HIV, pneumococcal disease
What are the characteristics of non-infectious diseases? Name some examples
Cannot be spread from one person to another
Not caused by pathogens but rather inherited or caused by factors such as air pollution malnutrition or lifestyle choices
Sickle cell anaemia, type 2 diabetes, liver cirrhosis and coronary heart disease
How are infectious diseases spread by droplets in the air?
When a person coughs or sneezes, numerous tiny droplets that may contain pathogens are expelled
Anyone within a close range may breathe in these droplets and maybe infected
Why is wearing a mask advised when there is a disease outbreak?
Reduces likelihood and severity of transmission and amount of pathogens released by a person into the air
How are infectious diseases spread by direct contact?
Exchanging bodily fluids during sexual intercourse
Blood from an infected person comes into contact with mucous membrane and the bloodstream through a break in the skin
Give an example of infectious diseases spread by direct contact
STIs such as HIV hepatitis b and syphilis can be transmitted from mother to baby while breast feeding
How are infectious diseases spread by contamination of food and water?
Food and water can be contaminated by pathogens when are not properly stored or handled
What are the methods to prevent food and water bourne diseases?
Practising hygienic food preparation and storage, personal hygiene, maintaining a clean water supply and ensuring proper sewage treatment
What are the characteristics of the influenza virus?
Caused by the influenza virus
Attacks respiratory system
Recovery within 2 weeks
May lead to complications such as pneumonia
How is the influenza virus transmitted?
Through air droplets
When a person touches a surface contaminated with the virus, then touches their mouth, nose or eyes
what are the symptoms of influenza
high fever, headache, stuffy nose, cough, sore throat, muscle aches
what are the 6 ways to reduce transmission of the influenza virus?
annual influenza vaccination
avoid coming into contact with people who have the flu and vice versa
if you are sick, cover your mouth and nose with tissue when you cough or sneeze and dispose it properly… or wear a face mask
wash your hands with soap and water or rub with disinfectant or hand sanitisers
avoid touching eyes nose and mouth
take antiviral drugs prescribed by a doctor to treat the illness
what are the characteristics of pneumococcal disease?
caused by pneumococcus bacteria
attacks different parts of the body
leads to serious infections of the lungs, blood and spinal cord
how is pneumococcal disease transmitted?
by respiratory droplets?
what are the signs and symptoms of pneumococcal disease?
fever cough headache chest pain vomiting rapid breathing
what are the 3 methods to reduce transmission of pneumococcus bacteria?
pneumococcal vaccination
daily preventive actions similar to influenza
- avoid cmg into close contact w ppl who have the disease
- if you are sick cover your mouth and nose with tissue or wear a mask and dispose it properly
- wash your hands with soap and water/ rub w disinfectant or hand sanitisers
- avoid touching eyes, nose and mouth
take antibiotics as prescribed by the doctor to treat the disease
what are vaccines?
contains an agent that resembles a pathogen and prevents infectious diseases by stimulating WBC to quickly produce antibodies when the pathogen invades
taken orally or through an injection
how do vaccines work?
antigens trigger the production of antibodies
when an antigen enters the body it stimulates the WBC to quickly destroy them
WBC binds to agent
WBC is stimulated to divide
WBC produce antibodies
antibodies destroy the agent in the vaccine
some of these WBC will remain in the bloodstream
- in the future if live pathogens enter the bloodstream, WBC will recognise them and quickly produced antibodies to destroy the pathogens bfr infecting our cells
what are antibiotics?
drugs to treat bacterial infections made by microorganisms and are used to kill/inhibit bacterial growth
how do antibodies work?
weakens the bacterial cell wall allowing water to enter the bacterial cell by osmosis, causing it to swell and burst
inhibits some enzymes which inhibits bacterial growth
prevents ribosomes from making proteins and enzymes, killing bacteria
breaking up bacterial cell membranes
why are antibiotics ineffective against viruses
viruses do not have cell walls, cell membranes or ribosomes
what are superbugs?
bacteria resistant to medicines such as antibiotics
what are the possible outcomes of taking a course of antibiotics
in a population of bacterial cells, some are more sensitive to the antibiotics while others are less sensitive
when antibiotic is taken, the bacterial cells that are more sensitive are killed
the bacterial cells that are less sensitive are not easily killed and may survive
if the prescribed course of antibiotics id not completed - less sensitive bacterial cells that survive will multiply and increase
if the prescribed course of antibiotics are completed
there is a higher chance that all bacterial cells are killed
how does antibiotic resistance occur?
overtime the subsequent generations of bacterial cells will be less sensitive to the antibiotics and may eventually become resistant
the antibiotic will not be able to kill the the resistant bacterial cells
other types of antibiotics will be required to treat the bacterial infection
what are the 3 ways to reduce antibiotic resistance?
not misusing or overusing antibiotics
completing the full course of antibiotics prescribed by doctors so that all bacteria are killed
using antibiotics only when necessary
