Midterm 2 - Lecture 11

Question 1

Who coined the term ‘Zoonosis’?

Answer 1

Rudolf Virchow

Question 2

Zoonosis

Answer 2

• any infectious disease that may be transmitted from animals to man or man to animals

Question 3

Zooanthroponosis

Answer 3

transmission from man to animal

Question 4

Anthropozoonosis

Answer 4

transmission from animal to man

Question 5

What animals with rabies are the most dangerous?

Answer 5

• cats and cows

Question 6

Definition of ‘emerging infectious diseases’

Answer 6

Diseases of infectious origin whose incidence in humans has increased in the last two decades or threatens to increase in the near future

Question 7

What are the 3 categories of emerging disease agents?

Answer 7

1. Previously known agents in a new geographic location (bad situation)
2. known agent presenting in a previously unsusceptible species (naive species)
3. previously unknown agent detected for the first time… its been suggested that the agent always been present, just never identified (bad situation)

Question 8

Why has no effort been made to categorize pathogens in wildlife?

Answer 8

• list would be enormous and lack of knowledge about existing diseases in wildlife
• however, we are getting closer with wildlife so potential for emerging diseases is increasing

Question 9

What 6 factors impact emerging diseases?

Answer 9

1. human demographics and behaviour
2. technology and industry (GLOBALIZATION)
3. economic land use and development
4. international travel and commerce
5. microbial adaptation and change
6. disruption of public health measures

Question 10

Disease maintenance

Answer 10

• each new host has to be a source infection for at least one other host to maintain disease in population

Question 11

Disease propagation

Answer 11

• each new host has to be a source infection for more than one other host to propagate the disease in population

Question 12

What does disease propagation and magnitude of disease outbreak depend on?

Answer 12

• spatial and temporal factors: population density, time point and duration of contact, host susceptibility, transmissibility of agent and agent virulence and host infectiousness

Question 13

Spatial components that affect disease propagation and magnitude of outbreak

Answer 13

• distance btw infectious individuals, terrain, soils, vegetation, climate, topography

Question 14

Temporal components that affect disease propagation and magnitude of outbreak

Answer 14

• the infected host may move across space/distance prior to contact with susceptible individual

Question 15

What is the causative agent of influenza?

Answer 15

Orthomyxovirus
- likes to mutate = more chances the agent has at invading our immune response

Question 16

What are the 3 types of influenza?

Answer 16

1. Type A (most virulent)
   - multiple species
2. Type B
   - humans
   - mild symptoms
3. Type C
   - humans and swine
   - rare
   - mild symptoms

Question 17

What is the most virulent strain of Influenza?

Answer 17

Type A

Question 18

How is Influenza A classified?

Answer 18

• on surface antigens
• Hemagglutinin (16 types): these antigens bind the virus to the cell
• Neuraminidase (9 types): these antigens cleave neuraminic acid from mucin allowing viral release from the cell

Question 19

Low vs High Pathogenic viruses of Influenza A

Answer 19

Low path
- very mild illness in poultry and rarely affect man
- all have the potential to convert into high path influenza viruses

High Path
- high mortality in ducks and poultry and severe to fatal diseases in man

Question 20

Fowl Plague

Answer 20

• highly infectious
• mortality near 100%; 2-12 days after clinical signs; sudden death
• drop in egg production
• CNS signs and respiratory signs

Question 21

What is the ‘problem’ with influenza?

Answer 21

• zoonotic-birds and pigs (pigs act as a bioreactor, a ‘vessel for mutation’)
• avian influenza binds to swine glycosides; swine generate a poor antibody response
• humans and pigs have similar internal protein genes and human influenza easily infects pigs
  = swine viruses are both avian-like and human-like

Question 22

What are among the most important public health risks facing humanity?

Answer 22

• emerging zoonotic diseases