B3 - Infection and response Flashcards
what are pathogens?
microorganisms that enter the body and cause disease
what is a communicable disease?
an infectious disease that can be easily spread
how do bacteria make you feel ill?
by producing toxins that damage your cells and tissues
which is bigger - bacteria or viruses?
bacteria are about 100 times bigger
what is a vector
an organism that carries and spreads a disease without getting ill itself
name two bacterial diseases
salmonella and gonorrhoea
what are some symptoms of salmonella?
fever, stomach cramps, vomiting and diarrhoea
what are the symptoms of salmonella caused by?
the toxins that the bacteria produce
how can you get salmonella food poisoning?
by eating food that’s been contaminated with salmonella bacteria
how is gonorrhoea passed on?
it is a sexually transmitted disease (STD) so it is passed on by sexual contact
what are some symptoms of gonorrhoea?
pain while urinating, a thick yellow or green discharge from the vagina or penis
what was gonorrhoea originally treated with, and why is this no long as effective?
it used to be treated with penicillin, but this has become trickier now because strains of the bacteria have become resistant to it
how can the spread of gonorrhoea be prevented?
people can be treated with antibiotics and should use barrier methods of contraception, such as condoms
what are 4 things we can do to reduce or prevent the spread of a disease?
- being hygienic
- destroying vectors
- isolating infected individuals
- vaccination
how does being hygienic help to reduce the spread of a disease?
using simple hygiene measures can prevent the spread of a disease. For example, doing things like washing your hands thoroughly before preparing food or after you’ve sneezed can stop you infecting another person
how can isolating infected individuals help to reduce the spread of a disease?
if you isolate someone who has a communicable disease, it prevents them from passing it on to anyone else
how can vaccination help to prevent the spread of a disease
vaccinating people and animals against communicable diseases means that they can’t develop the infection and then pass it on to someone else.
how do vaccinations work?
vaccinations involve injecting small amounts of dead or inactive pathogens. These carry antigens, which cause your body to produce antibodies to attack them - even though the pathogen is harmless (since it’s dead or inactive). If live pathogens of the same type appear after that, the white blood cells can rapidly mass-produce antibodies to kill off the pathogen
what does the MMR vaccine contain?
weakened versions of the viruses that cause measles, mumps and rubella
what are the pros of vaccination?
- vaccines have helped control lots of communicable diseases that were once common in the UK. Smallpox no longer occurs at all, and polio infections have fallen by 99%
- epidemics can be prevented if a large percentage of the populations is vaccinated. That way, even the people who aren’t vaccinated are unlikely to catch the disease because there are fewer people able to pass it on. But if a significant number of people aren’t vaccinated, the disease can spread quickly through them and lots of people will be ill at the same time
what are the cons of vaccination?
- vaccines don’t always work - sometimes they don’t give you immunity
- you can sometimes have a bad reaction to a vaccine, but this is very rare
how do we slow down the rate of development of strains of bacteria that are resistant to antibiotics?
to slow down the rate of development of resistant strains, it’s important for doctors to avoid over-prescribing antibiotics, and that you finish the whole course of antibiotics and don’t just stop once you feel better
where was aspirin developed from?
a chemical found in willow
what is digitalis used to treat?
heart conditions
what was digitalis developed from?
a chemical found in foxgloves
what happens in the first stage of drug testing?
- in preclinical testing, drugs are tested on human cells and tissues in the lab
- however, you can’t use human cells and tissues to test drugs that affect whole or multiple body systems
what happens in the second stage of drug testing
- they test the drug on live animals. This is to test efficacy, toxicity, and to find the best dosage
- the law in britain states that any new drug must be tested on two different life mammals. Some people thinl it’s cruel to test on animals, but others believe this is the safest way to make sure a drug isn’t dangerous before it’s given to humans
what happens in the third stage of drug testing?
- the drug is tested on human volunteers in a clinical trial
- first, it’s tested on healthy volunteers to make sure that it doesn’t have any harmful side affects when the body is working normally
- if the results are good, the drug is tested on people suffering from the illness. The optimum dose is found
- the drug is tested against a placebo in a blind, or often double-blind trial
- the results of drug testing and drug trials aren’t published until they’ve been through peer review. this helps to prevent false claims
what are double-blind trials?
trials where neither the patient nor the doctor knows whether the patient is receiving a real drug or a placebo
