Origins of disease Flashcards
How has disease evolved?
Over time and space
Why have diseases appeared?
- urbanisation
- wars
- migrations
- discovery of the americas
- introduction of domestication of plants and animals
What is disease the center of?
Man, animals and the environment
Up until when was homosexuality seen as a disease?
1974
Preliminary definition of diseases
Diseases are ways of functioning of an individual body that are maladaptive with respect to the environmental context
What is illness?
The persons subjective experience of their symptoms
What is sickness?
Social and cultural conceptions of this condition
Another definition of disease
Diseases are functions that molecules and cells perform individually and through physiological supplements are the result of natural selection
What are external factors of disease?
As a consequence of smoking you get lung cancer
What are internal factors of disease?
Due to a genetic disease i.e. presence of BRAC1 you get breast cancer
What causes do diseases have?
Remote or evolutionary causes
They do not have only one or more proximate causes
What prevails over the well-being of the organism?
fitness
How does natural selection work?
- withing a species there are slight differences among individuals
- some individuals have characteristics which make them better able to survive than others
- these individuals are likely to live longer, breed and produce more offspring
- if the characteristic that helped the parent survive is passed on to the offspring, there will be more individuals with this character
- After several generations individuals with the favourable characteristic will be most common
What can natural selection cause?
Noticeable evolutionary changes in a species
How do mutations in the environment arise?
They are chance-driven
What does the frequency and distribution of each disease depend on?
On endogenous factors such as infectivity, virulence, vector and on the frequency and distribution of all the other diseases within the same population
What is one health?
Relies on the idea that health, animal welfare and respect for the environment are interconnected
human health and animal health are interdependent and both depend on the environment
What are example of one health?
misuse of antibiotics creates drug resistant infectious agents that endanger human health
climate change
What is the hygiene hypothesis for allergic diseases?
Children growing up in rural areas, around animals and in larger families seem to develop asthma, autoimmune and allergic diseases less often than do other children. This is due to the decreased exposure to viruses etc.
What was the origin of randomised contolled trial?
Sir James Lind in 1753 would allocate different food substances to see which one would help cure the symptoms of scurvy
What is pellagra?
Disease caused by a lack of vitamin B3
What is cretinism?
Congenital iodine deficiency syndrome
What is ergotism or Saint Anthony’s fire?
Ingestion of the alkaloids produced by a fungus that infects rye
What is the epidemic preparedness index (EPI)?
Has been created to prepare ourselves for new pandemics. 1.5 million viruses have been researched.
What correlation did David Barker notice?
The poorest regions of England and Wales were the ones with the highest rates of heart disease
What did Barker conjecture?
When there is inadequate food supply, the fetus diverts nutrients to its most important organ, the brain, while skimping on other parts of its debt: a debt that comes due decades later in the form of a weakened heart.
What does the thrift gene hypothesis state regarding early-life metabolic adaptations?
Early-life metabolic adaptations help in the survival of the organisms by selecting an appropriate trajectory f growth in response to environmental factors
What is common in the evolution of resistance to disease?
Trade-offs
What is the malaria hypothesis?
Disorders had become common in these certain areas because natural selection increased the prevalence of these traits to protect individuals from malaria
When did smallpox emerge?
3000/4000 years ago in East Africa
What are the 2 types of viruses that can smallpox?
Variola minor: more common and more severe
Variola major
When was the phenomenon of natural immunisations first described?
In Thucydides’ writing
When was the Antonine plague?
Rome 165-180 AD: smallpox
How does the Antonine plague show the power diseases have over politics?
Because it killed the last Roman Emperor, Marcus Antoninus
When was the Justinian plague?
541-750 ca
Describe briefly the Justinian plague?
killed 50-60% of the population
caused by the bacteria Yserina pestis
epidemic velocity suggests human-human transmission was pneumonic
When was the bubonic plague?
1330s-1879
Describe briefly the Bubonic plague
killed 50 million people
cross-species transmission
What is the Cross-species Transmission?
Transmission from one species to the next
One health approach of the bubonic plague
the epidemic subsided when the Norwegian rate out-competes and therefore ecologically displaces the previous rat in Europe
Where would most plague outbreaks happen?
In the periphery of trade routes and ports
What was the result of globalisation?
The time for epidemics to form decreased
What disease was brought to South America and which disease in return affected Europeans?
To south america: smallpox
from south america: syphilis
What was the first practice of immunisation?
Blowing in the nostrils of heatlhy people powder crusts extracted from individuals with milder forms of smallpox in the 17th and 18th century
What is mithridatism?
The possibility to acquire immunity to poisons through gradual exposure to them
What was the first form of vaccination?
smallpox
When was the smallpox vaccination introduced?
in 1796 by Edward Jenner
When was the origin of vaccine inoculation released?
1801
Why was using cows a success for the variolation of smallpox?
- cowpox had preferable side effects compared to small pox
- cows could be put in a serial culture to produce large amounts of vaccinal matter
- easily transported into villages
What was the first bacterium to be proven the cause of disease?
Bacillus anthracis: the cause of anthrax by Robert Koch
What were Koch’s postulates?
- The microorganism must be isolated from a diseased organism and grown in pure culture and identified
- The cultured microorganism should cause disease when introduced in a healthy organism when injected
- THe microorganism must be reisolated from the inoculated, diseased experimental host and identified as being identical to the original specific causative agent
Method of vaccination
isolation of pathogen
cultivate them
attenuate them: through feat, filters or chemical agents
inject them
immunise
Describe the anthrax experiment
Pasteur: 1881
5th may 1881: 60 sheep, 25 were inoculated with a weak does of anthrax, 50 were given the deadly disease, 10 were left for comparison
2nd June 1881: the 25 sheep that were innoculated survived and the rest died
Who is the father of modern antisepsis?
Joseph Lister
What were the methods suggested by Pasteur to get rid of microorganisms?
- FIlter them out
- Heat them up
- Expose them to chemical solutions
What method did Jospeh Lister use to sterilse human wounds?
Carbolic acid: lead to the rise of sterile surgery and germ theory
