Chapter 29 Flashcards Preview

MicroBiology > Chapter 29 > Flashcards

Flashcards in Chapter 29 Deck (46):
1

What is a well adapted pathogen

one that lives in balance with its host

2

What are chronic infections

host and pathogen survive

3

Three steps of an acute infection

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

4

Stages of a disease

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

5

Difference between mortality and morbidity

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

6

Worldwide deaths due to infectious diseases

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%

7

What is the myxoma virus

Biocontrol of rabbits in Australia

8

Steps of host-to-host transmission

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

9

What is herd immuinity

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

10

What happens in herd immunity

immunized people protect nonimmunized and pathogen cannot be passed on

11

Common themes of all modes

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

12

Major mneans of human infectious diseases transmission

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)

13

What is transmission facilitated by and what are the they?

Agents:
living agents: vectors
nonliving: vehicles and formites

14

What is zoonosis

disease primarily infection animals
occasionally transmitted to humans

15

know the cycles of host infection

know the cycles of host infection

16

Steps of schistosomiasis

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

17

Eggs developed for miracidia

sporocysts -> rediae -> cercariae

18

what are common source epidemics

usually from water and food contamination
cholera

19

examples of host-to-host epidemics

influenza
chickenpox

20

There is also cyclical and seasonal diseases

There is also cyclical and seasonal diseases

21

what are carriers

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

22

what are ways carriers can be identified

culture and immunoassays

23

What is a basic reproduction number

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

24

Know table

know reproduction table

25

Controls against common vehicles

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

26

Controls against major reservoirs

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

27

Controls directed against transmission

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

28

What is the only pathogen that has been eradicated

smallpox, polio is a goal but not completely yet

29

AFRICA CHART

AFRICA CHARt

30

what are diseases that suddenly become prevalent

emergent

31

reemerging diseases are

diseases that become prevalent after being under control

32

EMERGING AND REEMERGING DISEASES TABLE

EMERGING AND REEMERGING DISEASES TABLE

33

name some emergent factors

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

34

cholera pandemic

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

35

how was cholera an epidemic

sewage treatement brokedown (flood, hurricane etc)

36

influenza pandemic

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

37

ways influenza has major changes in genome

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

38

what is the 2009 pandemic

swine flu, example of gene reassortment

39

What is microbial (biological) warfare

use of bilogical agents to kill

40

what is biological warfare break

against the Geneva Conventions

41

Characteristics of microbial weapons

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

42

small pox details (as a weapon)

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

43

anthrax details (as a weapon)

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

44

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

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

45

characteristics of weapons grade anthrax

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

46

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

Clostridium botulinum
Clostridium tetani (tetanus)