Natural History Diseases course without any medical intervention Prepathogenesis 3 factors Agent Host and Environment Natural History Agent factors Related with self ID: 934596
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Slide1
PG- 1
st
year
21.07.2020
Slide2Natural History
Diseases
course without any medical intervention
Pre-pathogenesis:
3 factors
Agent
Host and
Environment
Slide3Natural History
Agent factors
Related with self
Related with man
Related with environment
Slide4Natural History
Related
to self
Biological → Morphology, life cycle, motility, temperature, oxygen demand and toxin production
Physical → resistance, viability for heat, dryness, UV light, chemical antibodies and
Chemical → antigen composition
Slide5Natural History
Related
to man
Infectivity → ability of agent to invade or multiply in host e.g. low infectivity in Clostridium diphtheria
Pathogencity
→ capability of agent to cause disease in host
Tubercle
bacilli→ highly pathogenic and Rabies → low pathogenic
Slide6Natural History
Virulence → degree of
pathogenicity
Tubercle bacilli → low virulent and Rabies → highly
virulent
Antigencity
→ ability of an agent to stimulate host to produce antibodies
High
pathogenic→ high antigenic
Slide7Natural History
Related to environment
2
role
(
a) as a reservoir
(
b) as a vehicle
Slide8Natural History
As
reservoir:
3
types
Human reservoir : In man as case /carrier
Kinds
Temporary carriers :
Healthy contacts of cases
of diphtheria.
Incubatory carriers :
Diphtheria
in Incubation
Period
Convalescent carrier :
Recently
recovered
from
typhoid
Chronic carrier :
Dysentery
Slide9Natural History
Domestic reservoir : e.g. dog (rabies), rats (plague)
Inanimate reservoir: soil (tetanus), water / sewage (cholera and typhoid)
Slide10Natural History
As
vehicle:
3
types
Physical →
fomites
, infected food, and water
Biological → mosquito/fleas
Social → venereal diseases, leprosy, measles
(genital / direct / skin / droplet) diphtheria
Slide11Natural History
Host
factors
i
. Age
ii.
Sex
iii
. Race
iv
. Genetic
v
. Personality
vi.
Habits and Custom
AGE:
Below 6 month → measles → resistant, from 6 months to 2 yrs → susceptible
Pertussis
→ susceptible under 2 yrs age
Typhoid → common from 5 to 25 yrs
Slide12Natural History
SEX:
Leprosy → common in male
UTI
by E. coli → common in female
AIDS
→
common in homosexual male
RACE:
P.
vivax
infection → Negroes is low than white in USA and even in western Africa.
Slide13Natural History
GENETIC
:
Sick cell trait / sickle cell disease other
haemoglobinopathies
→ effected individual are prone to infection of Salmonella,
Pneumococci
etc
Osteomyelitis
is also common.
Slide14Natural History
PERSONALITY
:
Some people are very much careful about their health and follow preventive measure → such life style
minimizes
the rate of infection and vice versa.
HABITS AND CUSTOM
:
like washing hand before meal protect from cholera while defection in open field spread hookworm infestation.
Slide15Natural History
Environmental
factors
Role of environment in infectious disease
Better socioeconomic
condition
better health and medical facility, better immunity and resistance
Improper disposal of waste
Slide16Natural History
Water and soil pollution
Altitude, soil, climate, rainfall, water etc
related
with spread of agent, reservoir and vectors
Arthropods, pets, live stocks
liable
to contact diseases
Slide17Pathogenesis
Entry of infectious agent into body result →
Agent fail to lodge in body or
Lodge and multiply but fail to produce disease or
Lodge, multiply and produce series of changes as fallows:
Preclinical : No sign and symptoms
Clinical : Sign and symptoms are there depending on agent, host and environment
Slide18May be mild / missed / ambulatory / atypical or → recovery
May be Acute or chronic
Acute → recovery / disability/death
Chronic → recovery /disability / death
Pathogenesis
Slide19Pathogenesis
Spectrum of disease
Sequence of events occur during contact with agent up to appearance of disease → may be fatal
Component
of spectrum
Preclinical and
Clinical
Gradient of infection relates with infection diseases
Inapparent
cases are responsible for transmission
Latent cases does not shed infectious agent
Gradient in
Inapparent
infection → mild → moderate → severe → fatal
Slide20Inevitability of
death-
unani
concept
Dehydration of body is essential
Excess of moisture is early stage of development reduce by innate heat
Body consumes moisture and dries it steadily
Slide211
st drying process but later becomes fest → drying continuous till all the moisture vanishes and finally innate heat itself becomes extinct
Dryness increase in two ways:
Reduce intake of requisite material
Dispersion of body fluid
Inevitability of death
Slide22Inevitability of death
Heat decreases in two ways
Excessive dryness in substance of tissue.
Progressive decreases of innate moisture.
Innate heat thrives on innate moisture overwhelmed by extraneous moisture
Slide23Innate heat (metabolic activity) decreases as extraneous moisture increases due to weakness of digestion
When innate moisture dries up innate heat comes to an end → result in physical death
Life is not entirely dependent upon innate moisture
To cope with dispersive effect of heat (whether innate heat of body and extrinsic heat generated by activity of body organs)
Inevitability of death
Slide24Inevitability of death
Dispersion of innate fluid replenished by intake of food → this is not an everlasting action of food
Knowledge of health preservation could not avoid death, external affliction and extend the life
Aim of preservation of health is to arrest dispersal of innate moisture
Slide25Span of life is fixed for an individual according to original temperament i.e. to innate heat and moisture (vital fluid)
Some people die early due to prematurely dries and disperse of vital fluid → a natural death or by
mimical
manner as drowning, wound injuries → unnatural death.
So health is preserved to reach it normal life span by ensuring suitable condition
Inevitability of death
Slide26Inevitability of death
Two responsible faculties of health preservation
Nutrition
→ for replacement of wear and tear of tissue
Vital
→ for replacement of wear and tear of vital force
Foods form our part of body after digestion
Absorption and eliminated residual parts and converted into tissue with the help of special organs.
Slide27Inevitability of death
So for death
preservation of
balance in six essentials causes should be ensured specially
Maintenance of balanced temperament in varying condition
Consumption of suitable food and fluid
Proper elimination of waste product
Care and protection of organs
Slide28Purity of inhaled air
Healthy environment and
Moderation in physical mental, sleep and wakefulness
For preservation of health
management
is described separately for child, adult and elderly people in detail
Inevitability of death
Slide29END
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