Chapter 29 Flashcards

1
Q

What is a well adapted pathogen

A

one that lives in balance with its host

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2
Q

What are chronic infections

A

host and pathogen survive

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3
Q

Three steps of an acute infection

A
  1. short term infection
  2. rapid and dramatic onset of disease
  3. host returns to good health
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4
Q

Stages of a disease

A
  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
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5
Q

Difference between mortality and morbidity

A

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

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6
Q

Worldwide deaths due to infectious diseases

A
  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%
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7
Q

What is the myxoma virus

A

Biocontrol of rabbits in Australia

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8
Q

Steps of host-to-host transmission

A
  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
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9
Q

What is herd immuinity

A

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

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10
Q

What happens in herd immunity

A

immunized people protect nonimmunized and pathogen cannot be passed on

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11
Q

Common themes of all modes

A
  1. escape from host
  2. travel
  3. entry into new host
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12
Q

Major mneans of human infectious diseases transmission

A
  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)
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13
Q

What is transmission facilitated by and what are the they?

A

Agents:
living agents: vectors
nonliving: vehicles and formites

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14
Q

What is zoonosis

A

disease primarily infection animals

occasionally transmitted to humans

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15
Q

know the cycles of host infection

A

know the cycles of host infection

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16
Q

Steps of schistosomiasis

A
  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
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17
Q

Eggs developed for miracidia

A

sporocysts -> rediae -> cercariae

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18
Q

what are common source epidemics

A

usually from water and food contamination

cholera

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19
Q

examples of host-to-host epidemics

A

influenza

chickenpox

20
Q

There is also cyclical and seasonal diseases

A

There is also cyclical and seasonal diseases

21
Q

what are carriers

A

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

22
Q

what are ways carriers can be identified

A

culture and immunoassays

23
Q

What is a basic reproduction number

A

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

24
Q

Know table

A

know reproduction table

25
Q

Controls against common vehicles

A

common: food, water, air

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

26
Q

Controls against major reservoirs

A
domestic animal reservoirs:
can be immunized or destroyed
wild:
elimination is impossible
insect:
insecticides and screens
27
Q

Controls directed against transmission

A

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

28
Q

What is the only pathogen that has been eradicated

A

smallpox, polio is a goal but not completely yet

29
Q

AFRICA CHART

A

AFRICA CHARt

30
Q

what are diseases that suddenly become prevalent

A

emergent

31
Q

reemerging diseases are

A

diseases that become prevalent after being under control

32
Q

EMERGING AND REEMERGING DISEASES TABLE

A

EMERGING AND REEMERGING DISEASES TABLE

33
Q

name some emergent factors

A

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
Q

cholera pandemic

A

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
Q

how was cholera an epidemic

A

sewage treatement brokedown (flood, hurricane etc)

36
Q

influenza pandemic

A

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

37
Q

ways influenza has major changes in genome

A

antigenic drifty: gene mutation (minor change)

antigenic shift: gene reassortment (major)

38
Q

what is the 2009 pandemic

A

swine flu, example of gene reassortment

39
Q

What is microbial (biological) warfare

A

use of bilogical agents to kill

40
Q

what is biological warfare break

A

against the Geneva Conventions

41
Q

Characteristics of microbial weapons

A
  1. easy to produce and deliver
  2. safe for use by the offensive soldiers
  3. able to incapacitate or kill individuals
42
Q

small pox details (as a weapon)

A

small pox: mortality rate 30% or higher.

while vaccine exists, efficacy against weapons-grade is untested

43
Q

anthrax details (as a weapon)

A
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
Q

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

A
  1. cutaneous (skin) 20% in untreated
  2. gastroinstestinal 50%
  3. inhalation close to 100%
45
Q

characteristics of weapons grade anthrax

A

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
Q

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

A
Clostridium botulinum
Clostridium tetani (tetanus)