Lecture 4: Malaria and Plague Flashcards
Flu is the most dangerous type of organism why?
we can have a flu that affects birds but it can mutate and humans can get it
what is vaccine acquired polio?
get vaccine and acquired polio from it
What is Jared Diamonds hypothesis?
hypothesis based on geo and food
- if ppl grew food other ppl could become engineers etc. allows pop. to advance
- led to segregation of pop
why was the initial smallpox vaccine so effective?
cowpox virus that was injected into body
- when we get vaccinated our immune system responds to whole organism
- naturally infected is better than vaccinated
Where did malaria originate from?
Believed to have originated among African primates
How is malaria transmitted?
Genus Plasmodium, transmitted via female mosquito (anopheles)
P. Vivax
infects young erythrocytes
P. Malariae
infects mature erythrocytes
P. Falciparum
infects both types of erythrocytes (most common in sub-Saharan Africa)
P. Knowlesi
infects both types (most common in Southeast Asia
Are erythrocytes acellular?
NO
- no nucleus or organelles
List the symptoms of malaria
Infection gives you a characteristic fever cycle.
◦ 2-3 days you have increased temperature 40 C - 42 C; not optimal temp regulated by hypothalamus
◦ The fever cycle occurs with a burst of Plasmodium from erythrocytes
◦ This is due to inflammation from the clean up of broken cells
Malaria and Immunity
- Innate immunity holds down the parasite count
- Acquired immunity produces antibodies but only after the person has survived
several attacks
◦ Only works on the strain causing the infection
Who is immune to malaria and HOW?
Natural selection (genetic evolution) in malarious regions has gradually supplemented acquired immunities by evolving innate resistances
- This is known as Sickle Cell Anemia
- we have evolved to create erythrocytes which couldn’t be infected by malaria
Individuals whose origins are in Africa (sub saharan african) may have acquired a genetic trait which protects them from…?
***Plasmodium vivax *
1/4 of the population has this genetic trait.
Explain the Plasmodium Vivax transmission?
If two people mate and pass on the sickle cell trait, the resulting offispring will have S.C.Anemia
sickle cell anemia
trait which causes the erythrocytes to turn sickle in shape
- prevents plasmodium from entering
How fatal is malaria?
- About 1.5 million to 3 million people die every year (85% of these occur in Africa),
accounting for about 4-5% of all fatalities in the world - One child dies of malaria somewhere in Africa every 20 sec, and there is one malarial
death every 12 sec, somewhere in the world. - Malaria kills in 1 year what AIDS killed in 15 years. In 15 years, if 5 million have
died of AIDS, 50 million have died of malaria.
Why does HIV get so much funding and malaria does not?
malaria doesnt affect western society only Asian and African which ppl dont care abt
- Estimated worldwide expenditure per malaria fatality: $ 65, as compared to $ 3274 for HIV/AIDS and $ 789 for asthma. That is to say, one HIV/AIDS death is equal to about 50 malaria deaths.
Malaria ranks third among the major infectious diseases in causing deaths after
pneumococcal acute respiratory infections and tuberculosis. It is expected that by the turn of the century, would be the number one infectious killer disease in the world.
* Every year - 30,000 visitors to endemic areas develop malaria and 1% of them may die
* Estimated worldwide expenditure on malaria research: US $ 58 million, one thousandth of the US $ 56 billion spent globally on health research annually
Describe where malaria vector species are prevelant in the world
As observed malaria strains are prevalent across the world, however methods of treatment and prevention are not globally applicable. What might work in Europe and Asia might not work in sub-Saharan Africa.
vaccine equity
impossible to vaccinate everyone b/c impossible to transport vaccine that require -80 degrees celcius temp for ex
Where are malaria death rates the highest?
As observed majority of malaria related deaths are prevalent in African countries.
What is the general rule of thumb with diseases?
◦ Those who live in close proximity to a particular pathogen for long enough, develop an ability to live with the disease.
we see this with malaria; virus wants to live with you not kill you if it kills host it cannot survive either
- homeostatic relationship: pop. to large virus comes and decreases pop
Why does it not make sesne when on the news we hear “new varaiant is more deadly” ?
we have not seen a virus that has increased in pathogenictity in a pop.
What are the diseases that are difficult to live with?
Plague, small pox, mumps, Ebola
- b/c virus evolves with pop if they weree to kill everyone virus can’t live anymore
When did new plagues hit socities?
New plagues first hit humankind around 3000 BC. when cities over 50,000 were sprung up in Mesopotamia, Egypt, and Indus Valley
What happened in 500 BC?
is when pathogens had an impact on the growth of civilization in Asia and Europe.
- Generally these diseases would pass from human to human very quickly and need no intermediary carrier
- These new pathogens changed the course of human history
**One’s people disease became another people’s plague **
How did the spread of disease help the population?
disease outbreaks would control population growth
- Which made possible, the food surpluses that sped the development of cities -
because there was food, people didn’t all need to farm, people could study and
develop other careers - truths to Diamond’s hypothesis - Relatively recently, cities were so unhealthy that population could not replace themselves.
What were the sociteal impacts of the plague?
was responsible for mass human death, socioeconomic changes, and religious turnovers
plague= rodent disease
Where was the 1st documented outbreak of plague?
The first documented outbreak of the plague was in the Roman Empire ◦ Called the plague of Justinian
◦ Lost 1/4 of their population
◦ Devastated Constantinople in 542 AD
◦ Travelled to Mediterranean for two centuries
Has the plague been eradicated?
No still present today
- in london they get abt 100 cases every year
The Black Death
When did it begin? where
Second cycle of plague
◦ Greatest imprint on the population
Began in 1300 and ended in 1800
◦ Began in Asia and swept through Middle East, North Africa, and Europe
How did the Black death affect the population?
Europe alone lost over 20 million people
◦ Between 20% and 60% and higher died in cities
◦ Often forcing people to abandon their towns and villages for none infected areas
(this changed the socioeconomic of the cities)
- the upperclass would abandon the cities and go to their homes in the country leaving the poor on their own. People left in cities would occupy power positions that were left vacant.
What is the genus
Yersinia pestis
‣ Human and animal disease
List the 2 types of plague infections
which is more deadly
‣ Bubonicplague
‣ Pneumonic plague - much worse
Reservoir
Arthropod reservoir
How was plague transmitted?
◦ Bitten by rodent/flea that is carrying the plague bacterium
◦ Handling an infected animal ‘flea transmission’
Fleas become infected by feeding on rodents, such as chipmunks, prairie dogs, ground squirrels, mice, and other mammals that are infected with the bacterium Yersinia pestis. Fleas transmit the plague bacteria to humans and other mammals when it comes and bites you
Period of communicability
Susceptibility among the unvaccinated is universal
vaccine was actually not needed there were other ways to gte rid of the
Bubonic Plague
Infection of the lymph system
Signs occur 2 to 6 days after being infected
No person to person transmission
When plague is left untreated, plague bacteria invade the bloodstream
- Causes septicaemia
Lives in phagocytes cells which accumulate in the lymph nodes.
septicaemia
infection of the blood
If the bubonic plague is living in phagocytic cells what does that mean?
if its infecting phagocutic cells its hiding from immune system similar to HIV
phagocytyes; part of immune response
Pneumonic plague
infection of the lungs causes the pneumonic plague
sever respiratory illness with, high fever, chills, cough, and breathing difficulty with expel bloody sputum
- Person to person transmission
- There is also swollen lymph nodes
- Without antibiotic therapy, the disease can progress rapidly to death
What is bloody septum a symptom of?
cancer plague TB
What are the signs and symtpons of Plague?
- Most common form of human plague is a swollen and very tender lymph gland, accompanied by pain.
- Swollen gland is called a “bubo” (hence the term ‘bubonic plague’)
When should you suspect someone has the plague?
when a person develops a swollen gland, fever,
chills, headache and extreme exhaustion, and has a history of possible exposure to infected rodents, rabbits or fleas
