MGY277 UNIT 1 FINAL FLASHCARDS

How many recorded global deaths were attributed to COVID-19?

Approximately 7.1 million worldwide

How many COVID-19 deaths occurred in Canada?

Around 55,300 deaths

Why is COVID-19 mortality undercounted?

Limited testing, misattributed causes, unrecorded out-of-hospital deaths, and indirect health and social consequences

What are examples of indirect pandemic-related deaths?

Increased mortality from limited healthcare access, overwhelmed hospitals, untreated conditions, social instability, accidents, suicide, and homicide

What is excess mortality?

A measure comparing observed deaths during a crisis to expected deaths under normal circumstances, capturing direct and indirect losses

What is the estimated true global COVID-19 mortality based on excess deaths?

Over 18 million deaths worldwide

What is Long COVID?

Persistent symptoms lasting more than 3 months after initial infection

What symptoms are associated with Long COVID?

Fatigue, pulmonary dysfunction, muscle/chest pain, cognitive impairment, and neurological issues

What scientific advancement emerged from the COVID-19 pandemic?

Accelerated vaccine development and major progress in mRNA technology

Why was the COVID-19 vaccine developed so quickly?

Prior mRNA research, genome sharing, overlapping trial phases, rolling regulatory reviews, and massive funding

How has mRNA technology benefited beyond COVID-19?

It is now applied to other conditions, including new RSV vaccines and future rapid-response platforms

Why are future pandemics likely?

Global travel, climate-driven ecosystem changes, increased population density, and more human-animal contact

What biological trait helped SARS-CoV-2 spread globally?

Its ability to transmit before symptoms appear (pre-symptomatic transmission)

What does pre-symptomatic transmission mean?

Individuals can infect others before realizing they are sick

How has pandemic preparedness improved after COVID-19?

Enhanced WHO surveillance, global vaccine platform access, pandemic financial support, and rapid diagnostic development

How long have microbes existed compared to humans?

Microbes appeared 3.5–3.8 billion years ago, while humans emerged ~300,000 years ago

How have microbes influenced human survival?

Humans developed immune defenses to survive microbial threats, shaping biology and society

What historical impact have infectious diseases had?

They caused massive mortality and reshaped social, political, and evolutionary outcomes

What was the Black Death?

A pandemic caused by Yersinia pestis that killed ~50% of Europe’s population in under 10 years

How was the Black Death transmitted?

Through flea bites, with bubonic, pneumonic, and septicemic forms

Where is Yersinia pestis found today?

Still present in western North America, Africa, and Asia, treatable with antibiotics

What causes cholera?

Pathogenic Vibrio cholerae transmitted through contaminated water and poor sanitation

Why is cholera considered a “disease of inequality”?

Regions with poverty, war, and poor infrastructure continue to experience outbreaks

What is one historic example of cholera mortality?

In 1854, a cholera outbreak caused 616 deaths in 10 days

What was significant about the 1918 influenza pandemic?

It caused 17–50 million deaths in less than two years

What virus caused the 1918 pandemic?

A subtype of H1N1 influenza A

Which age group experienced high mortality during the 1918 influenza pandemic?

Healthy adults aged 20–40 years old

How have infectious diseases shaped the human genome?

About 30% of human adaptive mutations arose due to viral pressures

How has malaria influenced human evolution?

It imposed strong selective pressure favoring gene variants that resist infection

What is the sickle cell heterozygote advantage?

One mutated gene copy protects against malaria while two copies cause sickle cell disease

What causes African sleeping sickness?

Trypanosoma protozoa transmitted by tsetse flies

What APOL1 gene variants provide resistance to sleeping sickness?

G1 and G2 variants burst Trypanosoma parasites

What is the trade-off of APOL1 variants?

Increased protection against sleeping sickness but higher risk of chronic kidney disease

How might infectious disease relate to Neanderthal extinction?

Homo sapiens exposure to diverse microbes may have transmitted new pathogens to Neanderthals

How did malaria affect the American Revolutionary War?

British troops lacked immunity seen in local fighters, weakening the British campaign

How did yellow fever influence the Haitian Revolution?

Yellow fever killed large numbers of French troops while locals had greater resistance, aiding Haitian victory

What is the principle of germ theory?

The idea that microorganisms are capable of causing some diseases

What theory dominated before germ theory?

Miasma theory, which proposed diseases were caused by “bad air” or vapors from rotting matter

Why was miasma theory appealing at the time?

Disease was common in areas with poor sanitation and foul odors, making the connection seem logical

How did physicians react to early germ theory?

Many rejected it and were offended by suggestions to wash hands or accept microbial transmission

How were hospitals influenced by miasma theory?

They prioritized ventilation, high ceilings, and removal of foul smells rather than sterilization

Who was Agostino Bassi?

Scientist who suggested disease could be transmitted by living agents after observing dying silkworms

What disease did Bassi study?

A fungal disease killing silkworms, causing them to become covered in white powder

What was Bassi’s major contribution?

He demonstrated infection transmission by placing fungal spores from infected to healthy caterpillars

What control measures did Bassi recommend?

Separating infected organisms, destroying infected caterpillars, sanitizing hands and equipment

Who was Ignaz Semmelweis?

Physician who connected childbed fever to cadaver contamination by medical students

What problem did Semmelweis investigate?

Childbed fever killing 10% of birthing patients in hospitals

What discovery led Semmelweis to his hypothesis?

His colleague died from an autopsy cut with symptoms identical to childbed fever victims

What action did Semmelweis implement?

Mandatory handwashing and chlorine disinfection, reducing mortality by 90%

Why were Semmelweis’ findings rejected?

Physicians were offended at the implication they were responsible for deaths

Who was John Snow?

Physician considered a founder of epidemiology who investigated cholera transmission

What was John Snow’s hypothesis about cholera?

Cholera was waterborne, not spread through air or smell

What two water companies helped Snow test his hypothesis?

One drew cleaner water upstream, while the other drew sewage-contaminated water

How did Snow map cholera deaths?

By documenting household water sources and creating the famous “ghost map”

What evidence supported Snow’s waterborne theory?

Most deaths occurred in households using the Broad Street pump

Why should we care about medical microbiology?

It allows us to diagnose, treat, and prepare for infectious diseases that affect individuals and society

How does microbiology influence daily decision-making?

Understanding microbes informs choices about vaccination, treatments, hygiene, and disease prevention

What does the study of microbiology examine beyond classification?

How microbes impact health, history, technology, and our future

What is the goal of preparing for microbial challenges?

To prevent, respond to, and minimize impacts of infectious disease outbreaks

How does medical microbiology contribute to public health?

Through vaccine development, outbreak surveillance, antimicrobial strategies, and diagnostics

How are microbes connected to modern society?

They influence medicine, agriculture, biotechnology, pandemics, and ecosystem balance

What does studying pathogens teach us?

How microbes cause disease and how to stop or control their spread

Why are diagnostics important in infectious disease?

They help identify pathogens quickly, allowing effective treatment and outbreak control

How do microbes influence future innovation?

Microbial research drives new therapies, vaccines, biotechnology, and disease-resistant crops