Module 5

Question 1

Pandemic

Answer 1

• disease that is growing exponentially, that is each day the number of cases grow more than the day before

Question 2

Epidemic

Answer 2

• unexpected increase in the number of disease cases in a specific geographical area

Question 3

Outbreak

Answer 3

• can be used interchangeably with epidemic
• usually used for incidents in much smaller geographical areas than epidemics

Question 4

Endemic

Answer 4

• A disease that is consistently present but limited to a particular area, with predictable disease spread and rates

Question 5

Pathogen

Answer 5

any organism or biological agent that can cause disease

Question 6

How does a pandemic start

Answer 6

• arise from emerging infectious diseases

Question 7

Infectious disease

Answer 7

• one that is caused by some sort of biological agent (germs)
• contagious: can be transmitted from person to person

Question 8

Zoonotic disease

Answer 8

• one that is transmitted from animal to human
• most EIDs are zoonotic in origin

Question 9

Dead-End Host

Answer 9

human can’t further transmit the disease to other humans

Question 10

Emerging Infective Disease

Answer 10

• EIDs are contagious diseases that are rapidly increasing in number of cases, or the geographical range is changing
• sometimes an EID comes from a previously unknown pathogen (a novel pathogen) like COVID-19
• sometimes an EID is a previously observed pathogen but is reappearing or appearing in a new area

Question 11

Direct Contact Transmission

Answer 11

• coming into direct contact with saliva, blood, urine, feces, mucous, or other bodily fluids, of an infected animal
• can happen through scratches or bites
• how rabies infects humans

Question 12

Indirect Contact Transmission

Answer 12

• coming into contact with areas or surfaces where infected animals/people have been
• ex, chicken coups, toilets, barns, soil, counters, etc.
• ex. lassa fever is a viral illness that humans can acquire by inhaling dust contaminated with rat droppings

Question 13

More pandemics expected due to human activities

Answer 13

• food production
• wildlife trade
• climate change
• travel and transportation

Question 14

Different types of pathogens/pathogenic organisms

Answer 14

• fungi
• parasites (protists and worms)
• bacteria
• virus

Question 15

Fungi

Answer 15

• single or multi cellular organisms that get their food from breaking down biological materials in their environment (they are decomposers(
• approx 40 different species of fungi can cause ringworm
• candida is a type of yeast, a single-celled fungi, that can cause a variety of diseases in human including thrush

Question 16

Parasites (protists and worms)

Answer 16

• protists are single-celled organisms
• some of them cause disease and are considered parasites
• some can get inside your cells, like Plasmodium that causes malaria
• giardia can live in cold water for months and is a common cause water-borne illness
• worms are animals, there are many kinds of worms that can cause diseases (ex. heartworm disease in dogs is transmitted by mosquitoes)

Question 17

Bacteria

Answer 17

• simple, single-celled organisms
• the first living things to inhabit the earth
• most diverse and abundant group of organisms on earth
• there are more bacteria on the palm of your hand that there are humans on earth
• most bacteria does not cause disease, most bacteria is helpful
• we evolved alongside bacteria and could not survive without it

Question 18

Virus

Answer 18

• has no cells
• only made of protein and nucleic acid
• needs to infect a cell to make protein and reproduce
• typically much smaller than bacteria
• some viruses can infect bacteria
• use the genetic code of all living things

Question 19

Structure of a virus

Answer 19

• nucleic acid
• recognition spike
• capsid

Question 20

Structure of a virus: nucleic acid

Answer 20

all viruses have genes made of nucleic acid. while living cells use double stranded DNA, viruses may use DNA or RNA, and it may be single or double stranded

Question 21

Structure of a virus: recognition spike

Answer 21

each virus has one or more proteins that protrude into the environment and is capable of binding to proteins on the outside of its host cells. this protein-protein recognition is very specific, causing each type of virus to infect a specific type of cell

Question 22

Structure of a virus: capsid

Answer 22

outer coat of a virus made of one or a few different protein molecules repeated in a regular pattern, viral genes code for capsid proteins. once produced inside a cell, the protein parts spontaneously self-assemble into a new capsid

Question 23

How do viruses get into cells

Answer 23

• spike proteins help viruses get into cells
• shape of the spike protein determine what molecules it can bind to on the surface of a host cell
• viruses specific for certain cell type and species

Question 24

Process by which virus replicated in a cell

Answer 24

1. virus becomes attached to a cell
2. cell engulfs the virus
3. viral genetic materials are released in the cell, and begin replication using cellular mechanisms
4. cell replicated viral proteins, which begin forming new viral particles
5. new viral particles are released from the cell while the cell continues to replicate the virus within

Question 25

Viruses mutate

Answer 25

* as viruses replicate in the host cells, genetic materials can mutate * viruses can exchange genes with other viruses they encounter in the same host * some viruses, like influenza, mutate a lot * other viruses, like rabies, don't mutate often

Question 26

Variant

Answer 26

any virus with a mutation

Question 27

Strain

Answer 27

a variant that has distinct properties/behaviors compared to the original virus

Question 28

Potential consequences of viral mutations

Answer 28

1. no consequences 2. virus gains or loses ability to infect a specific host species or cell type 3. virus becomes more or less virulent 4. virus becomes more or less contagious 5. virus becomes more or less resistant to medications or vaccines

Question 29

More pandemics expected due to human activities: Globalization

Question 30

More pandemics expected due to human activities: Climate change

Answer 30

* as planet warms disease vectors like ticks and mosquitoes are able to survive and transmit disease in new geographical location and different seasons * ex. lyme disease is spread by deer ticks, deer tick habitat is moving further north as temp increases

Question 31

More pandemics expected due to human activities: Land use change

Answer 31

* urbanization and agriculture led to destruction of forests and other habitats for wildlife * likelihood of human-wildlife interaction increases * increased interactions with wildlife increases chances of zoonotic disease emergences