Epidemiology and Viruses Flashcards
Define ‘epidemic’ and identify the common causes
Identify the 2 ways epidemics are classified
Explain what a propagated outbreak is and provide an example.
Explain what a common source outbreak is and provide an example.
An epidemic is a sudden disease outbreak that affects a large number of people in a particular region, community, or population. Some common causes for epidemics is viruses or bacteria’s growing stronger or if people become more susceptible to diseases.
Classified as common-source or propagated.
Propagated: Happen when a disease is passed from person to person. Such as STD’s or the common cold.
A common-source outbreak occurs when a group of people get sick after being exposed to a virus, bacteria, toxin, or other infectious agent from the same source. Such as food poisoning.
Define ‘epidemiology’
Who was Jon Snow?
Explain his contribution to epidemiology
Describe the disease ‘cholera’ and how it is spread including the source of the disease.
Conclude how the London outbreak may have started and provide evidence.
Is there a cure or a vaccine? What other ways can you prevent getting the disease?
Epidemiology is the study of how often diseases occur in different groups of people and why.
Jon Snow was an epidemiologist who figured out the source of a Cholera outbreak
To find out where cholera was originated he used epidemiology before it was even really invented.
Cholera is a bacteria that spreads through water or food and it comes from human waste.
The London outbreak started by human waste being leaked into sources of water and food which is shown in the neighborhood of SoHo where cholera contaminated the water source.
To purify the water or cure the meat, avoid using water or meat that’s around many infections, keep up basic hygiene.
Explain active immunity
Explain passive immunity
Active immunity means one’s body produces antibodies to fight off the virus or another disease-causing agent. This happens after a specific disease is introduced to the body, whether through previous infection or a vaccine. This immunity usually is permanent and will last a person’s entire life.
Passive immunity means the antibodies were transferred from one person to another, like from mother to baby through the placenta or breastfeeding. Passive immunity usually lasts a few weeks to a few months.
Explain how viruses can change/mutate.
Explain why this then means current antibodies are no longer effective if a mutation has occurred.
Link this to current vaccines and how they aim to provide immunity against common viruses.
Viruses mutate by undergoing subtle genetic changes through mutation and major genetic changes through recombination. Mutation occurs when an error is incorporated in the viral genome.
Once a virus mutates antibodies can no longer recognize the virus as its different/changed and the antibodies need to match it to prevent its attack on the body.
When influenza virus drifts enough, vaccines against old strains of the virus and immunity from previous influenza virus infections no longer work against the new, drifted strains. A person then becomes vulnerable to the newer, mutated flu viruses. Antigenic drift is one of the main reasons why the flu vaccine must be reviewed and updated each year, to keep up with the influenza virus as it changes.
How does vaccines prevent a person getting disease?
A vaccine is a tiny weakened non dangerous fragment of the organism and includes parts of the antigen. It’s enough that our body can learn to build the specific antibody then if the body encounters the real antigen later as part of the real organism, it already knows how to defend it.
