Pathogens shaping history

L15

What pathogen is responsible for the bubonic and pneumonic plagues?

yersinia pestis

What are symptoms of the bubonic and pneumonic plagues?

buboes (swollen lymph glands) and pneumonia lungs + flu like symptoms and sepsis

What is the virulence of the bubonic plague?

50 %

What is the virulence of the pneumonic plague?

90 to 100%

When are the pneumonic and bubonic plagues treatable?

 if antibiotics < 24 h since first symptoms

Can zoonotic pathogens cause human disease?

yes but have an animal reservoir

What types of organisms does the Yersinia pestis pathogen infect? What is this termed?

rodents and wild dogs so zoonotic pathogen

What are the 2 pathways

• sylvatic: wild rodents + infective flee direct contact with a human - may progress to person-to-person transmission

• urban: domestic rodent + infective flea contact with human - may progress to person-to-person transmission

What is the type of transmission in the plague that needs to be avoided at all cost, bc causes most deaths?

person-to-person transmission

What is an epizootic?

animal equivalent of an epidemic

What drove the black death plague?

goods trafficking from Indochina then from everywhere - still don’t know the reservoir though (rats? humans? camels?)

What are factors for the catastrophic black death?

• no understanding of infectious diseASE

• NO TREATMENT

• POOR HEALTH DUE TO POOR DIET

What were benefits of the Black Death? Did these help avoid death from the plague?

improved personal hygiene, people drank boiled drinking water, burned bodies to avoid further infections

not at all

Where does quarantine come from?

italian, quaranta giorni = 40 days

What part of the population died in France, Italy, Spain?

70 to 80%

What part of the world population died from teh Black Plague?

20%

What is an organism that can’t be infected by a pathogen?

viruses

What causes the late blight/potato blight?

Phytophthora infestans

What is the reservoir of the potato blight? What are treatments?

Very stable spore structures

Fungicides (limited use bc as soon as stop = comes back bc spores still there)

Copper Sulphate - but eating these potatoes = toxicity

What is the virulence of the potato blight?

almost 100% of crops especially if soil pre-contaminated

Why is the blight not a problem in Peru?

bc of huge diversity of potatoes, if one type dies/is infected then the others will still be fine

Why is the blight a problem in Europe?

very low potato diversity = if one potato is diseased within the monoculture of potatoes then all impacted, all just as susceptible as the other

What are factors explaining why the potato blight was so devastating in Ireland?

had very little food already + very small crops so only crop useful were potatoes bc lots of nutrition for less room so everyone had that as their crop so no potatoes = no food = death

What pathogen causes the flu ie influenza?

influenza virus

What are symptoms of influenza?

Fever, Chills, Cough, Chest pain, Sore throat, Muscle pain

What is the virulence of influenza?

Very varied 0.01% - 50% mortality ‘newer’ strains have higher case fatality rates.

What are the major virulence factors of influenza?

Changes in the H (hemagglutinin) and N (neuraminidase) proteins on the outside of the virus

What does the H1N1 strain name refer to?

subtypes 1 of both hemagglutinin and neuraminidases, proteins found on the surface of the flu virus

What’s the reservoir for influenza?

humans, respiratory droplets

What does re-assortment of influenza genetic material refer to?

2 or more virus strains will infect a same cell, in the cell the chr./genetic material will reassort = new virus made = lots of genetic diversity

What types of changes throughout history are pathogens responsible for?

economic, social and scientific changes