Chapter 29

Question 1

What is a well adapted pathogen

Answer 1

one that lives in balance with its host

Question 2

What are chronic infections

Answer 2

host and pathogen survive

Question 3

Three steps of an acute infection

Answer 3

1. short term infection
2. rapid and dramatic onset of disease
3. host returns to good health

Question 4

Stages of a disease

Answer 4

1. Infection: organism invades and colonizes host
2. Incubation period: time between infection & onset of symptoms
3. acute period: the disease at height, overt symptoms present
4. Decline period: disease symptoms subsiding
5. Convalescent period: patient returns to normal state

Question 5

Difference between mortality and morbidity

Answer 5

mortality: incidence of death in a population
morbidity: incidences of diseases in a population that includes both fatal and nonfatal diseases.

Question 6

Worldwide deaths due to infectious diseases

Answer 6

1. Respiratory: 31% (bacteria, viruses, fungi)
2. Diarrheal diseases 15% (bacteria virus)
3. AIDS 13% (virus)
4. Tuberculosis 15% bacterium
5. Malaria 6% (protist)
   …
   Others 11%

Question 7

What is the myxoma virus

Answer 7

Biocontrol of rabbits in Australia

Question 8

Steps of host-to-host transmission

Answer 8

1. Virulence diminishes
2. Resistance of host increases
3. Pathogen extinction may occur if host killed before transmission
4. if no host to host transmission, pathogen may remain virulent

Question 9

What is herd immuinity

Answer 9

Resistance of a group to infection due to immunity of a high proportion of the group

Question 10

What happens in herd immunity

Answer 10

immunized people protect nonimmunized and pathogen cannot be passed on

Question 11

Common themes of all modes

Answer 11

1. escape from host
2. travel
3. entry into new host

Question 12

Major mneans of human infectious diseases transmission

Answer 12

1. person to person: direct contact (hand shake, sex), indirect contact (watercup), airborne droplets (sneeze cough)
2. Vehicle: (borne to all) water, food, air, soil
3. Vector: arthopods/insects (lyme disease, malaria)

Question 13

What is transmission facilitated by and what are the they?

Answer 13

Agents:
living agents: vectors
nonliving: vehicles and formites

Question 14

What is zoonosis

Answer 14

disease primarily infection animals

occasionally transmitted to humans

Question 15

know the cycles of host infection

Answer 15

know the cycles of host infection

Question 16

Steps of schistosomiasis

Answer 16

1. Embryonated eggs each with a fully developed miracidium are passed in feces
2. snail host ingests eggs, miracidia emerge from eggs and penetrate the snail intestine
3. cercariae released from snail
4. cercariae penetrate the skin of fresh brackish water fish
5. host becomes infection by ingesting undercooked fish contain metacercariae
6. metacercariae exyst in the small intestine
7. adult in small intestine

Question 17

Eggs developed for miracidia

Answer 17

sporocysts -> rediae -> cercariae

Question 18

what are common source epidemics

Answer 18

usually from water and food contamination

cholera

Question 19

examples of host-to-host epidemics

Answer 19

influenza

chickenpox

Question 20

There is also cyclical and seasonal diseases

Answer 20

There is also cyclical and seasonal diseases

Question 21

what are carriers

Answer 21

infected individuals with no/mild symptoms.
potential sources of infections
indiviuduals in incubation period

Question 22

what are ways carriers can be identified

Answer 22

culture and immunoassays

Question 23

What is a basic reproduction number

Answer 23

R0, and it is number of expected secondary cases from each single case, different infectious diseases have different R0

Question 24

Know table

Answer 24

know reproduction table

Question 25

Controls against common vehicles

Answer 25

common: food, water, air | food laws, water purification, but airborne pathogens are difficult to control

Question 26

Controls against major reservoirs

Answer 26

``` domestic animal reservoirs: can be immunized or destroyed wild: elimination is impossible insect: insecticides and screens ```

Question 27

Controls directed against transmission

Answer 27

immunization i.e. smallpox, tetanus isolation, quarantine, surveillance

Question 28

What is the only pathogen that has been eradicated

Answer 28

smallpox, polio is a goal but not completely yet

Question 29

AFRICA CHART

Answer 29

AFRICA CHARt

Question 30

what are diseases that suddenly become prevalent

Answer 30

emergent

Question 31

reemerging diseases are

Answer 31

diseases that become prevalent after being under control

Question 32

EMERGING AND REEMERGING DISEASES TABLE

Answer 32

EMERGING AND REEMERGING DISEASES TABLE

Question 33

name some emergent factors

Answer 33

human demographics i.e. urban vs rural changes in land use, i.e residential deforestation bulk processing and central distribution i.e. food and beverages international travel: i.e. airline (ebola) Microbial adapation and change i.e. RNA VIRUSES Breakdown of public health measures: i.e. cholera Natural disasters climate change: i.e. mosquitoes are moving northward

Question 34

cholera pandemic

Answer 34

cholera: causes severe waterloss diarrhea that occurs due to ingestion of contaminated water (usually occurs in developing countries) cholera was endemic: AFrica, SEA, Indian subcont, CA and SA

Question 35

how was cholera an epidemic

Answer 35

sewage treatement brokedown (flood, hurricane etc)

Question 36

influenza pandemic

Answer 36

occurs every 10-40 years that is casued by major change in genome

Question 37

ways influenza has major changes in genome

Answer 37

antigenic drifty: gene mutation (minor change) | antigenic shift: gene reassortment (major)

Question 38

what is the 2009 pandemic

Answer 38

swine flu, example of gene reassortment

Question 39

What is microbial (biological) warfare

Answer 39

use of bilogical agents to kill

Question 40

what is biological warfare break

Answer 40

against the Geneva Conventions

Question 41

Characteristics of microbial weapons

Answer 41

1. easy to produce and deliver 2. safe for use by the offensive soldiers 3. able to incapacitate or kill individuals

Question 42

small pox details (as a weapon)

Answer 42

small pox: mortality rate 30% or higher. | while vaccine exists, efficacy against weapons-grade is untested

Question 43

anthrax details (as a weapon)

Answer 43

``` easy to culture, and identify on petri plates w/ agar contains endospores 1. can store indefinitely 2. easy aerosolization 3. remain in environment for long time ```

Question 44

what are the three forms of anthrax disease and its mortality rates

Answer 44

1. cutaneous (skin) 20% in untreated 2. gastroinstestinal 50% 3. inhalation close to 100%

Question 45

characteristics of weapons grade anthrax

Answer 45

resistance to many antibiotics, vaccines should still provide some protection. enhanced for maximal dispersal (smaller and remain in air longer and travel farther) more scattered

Question 46

scientific name of the two bacterial toxins that can be used as weapons

Answer 46

``` Clostridium botulinum Clostridium tetani (tetanus) ```