Infectious Disease 3 and public health.pdf

Public Health

2. Dr. SamreenMisbah
MBBS, MPH, MHPE
Assistant Professor Community Medicine Department
Army Medical College, NUMS Rawalpindi

3. 
At the end of this 50 minutes session,
Students will be able to;
Discuss disease prevention and control
Discuss disinfection and types of
disinfectant
Learning Objectives

4. 
Disease Prevention & Control
•Reducing the
transmission of disease
agent at a low level that
it cease to be a public
health problem
Disease
Control

5. 
Disease Prevention &
Control
Basic approach is to
find weakest link in the
chain of transmission
of infection and to
break them
Requires sound
epidemiological
knowledge of the
disease

6. 
Disease Prevention & Control
Involves all the measures designed to prevent
or reduceas much as possible the incidence,
prevalence and consequences of disease
Requires
Community participation
Political Support
Inter-sectoralcoordination

7. 
Disease Prevention & Control
•1. Controlling Reservoir
•2. Interruption of
Transmission
•3. Protection of
susceptible Host
Control
Measures

8. 
1.General Control Measures
of Reservoir
Early
Diagnosis
Notification
Epidemiological
Investigation
Isolation
Treatment
Quarantine

9. 
Early Diagnosis
Needed for:
Treatment of patients
Epidemic investigation
Study time, place and person
distribution
Institution of prevention and control
measures

10. 
Notification
Notification to local health authorities to
provide medical care to hospitalized patients
and to operate control measures
A valuable source of morbidity data
(incidence and distribution of diseases)

11. 
Notification
Health administration are required to notify to
WHO Geneva of communicable diseases under
international health regulations (IHR)
(cholera, yellow fever, plague)
Diseases under surveillance by WHO
Louse borne typhus, relapsing fever, paralytic polio,
viral influenza A, SARS, malaria, smallpox

12. 
Notification
Also include Non-communicable diseases
Conditions like cancers, accidents, congenital
defects
Diseases to be notified vary from country to
country

13. 
Epidemiological Investigation
Characteris
tics of
Agent
Source or
Reservoir
Vectors
and
vehicles
Susceptible
host
populations
Climatic
condition
Social,
cultural and
behavioural
patterns
Geographi
cal
situation

14. 
Isolation
Applied to patients
Purpose is to protect the community by
preventing transfer of infection from the
reservoir to the possible susceptible hosts

15. 
Isolation
Separation for the period of
communicability of infected person or
animal to limit or prevent the direct or
indirect transmission of infectious agent
Physical isolation of the cases and carriers,
preferably hospital isolation

16. 
Isolation
Distinctive value in diseases (diphtheria,
cholera, plague)
In diseases with large sub-clinical infection
and carrier state (polio, typhoid, hepatitis
A) disease can not be prevented
Unsuccessful in diseases which are highly
infectious before they are diagnosed
(mumps)

17. 
Isolation
Chemical isolation by rendering cases non-
infectious through rapid treatment in their
homes (STD, Leprosy, TB)
Because of these limitations and
improvements in epidemiological
technologies isolation is replaced by
Surveillance

18. 
Surveillance
Must follow the control measures
It is the continuous scrutiny of all the aspects of
occurrence and spread of disease that are
pertinent to effective control

19. 
Surveillance
Once control measures have been instituted,
their effectiveness should be evaluated
If control measures are not successful, failure
reasons should be identifiedand existing
measures modified and evaluation continues

20. 
Surveillance
Individual Surveillance of Infected person until they are
no longer risk to others
Local Population Surveillance; Malaria surveillance
National Surveillance Small pox surveillance after its
eradication
International SurveillanceWHO maintains surveillance
of important diseases e.g. polio, malaria, influenza etc.

21. 
Treatment
Objectiveis to kill the infectious agent
when it is still in the reservoir before it is
disseminated
Cut short the duration of illness
Reduces the communicability of disease
Prevents development of secondary
cases

22. 
Quarantine
Applied to Exposed Well Person
“Limitation of freedom of movement of such
well persons or domestic animals exposed to
communicable disease for a longest usual
incubation periodof the disease, in such a
manner as to prevent effective contact with
those not so exposed”

23. 
Quarantine
Absolute quarantine -applied to any means
of transport or container to prevent the
spread of disease reservoir or vector of the
disease
Modified Quarantine: exclusion of sick child
from school
Segregationrefers to the separation of a
healthy person from an infected person

24. 
2.Interruption of Transmission

25. 
2. Interruption of Transmission
Water can be a medium for transmission of
many infective disease; Water treatment will
eliminate this disease
Food borne disease can be prevented by clean
practices i.e. hand-washing, adequate cooking,
prompt refrigeration, withdrawal of
contaminated food

26. 
2. Interruption of Transmission
Vector-borne disease can be controlled by
measures directed towards vector and its
breeding places
Early diagnosis and treatment of patients
and carrier, personal hygiene and proper
handling of secretions and excretion in case
of droplet infection and droplet nuclei

27. 
3. Susceptible Host
Active immunization
Passive Immunization
Combined Active & Passive Immunization
Chemoprophylaxis
Non-Specific Measures

28. Disinfection, Sterilization, Antiseptic

29. 
Disinfection
Thermal or chemical Disinfection-destruction of
most recognized pathogens but not bacterial
spores
Disinfectant; “A substance which destroys
harmful microbes (not usually spores) with the
objective of preventing transmission of disease”
It is applicable to only inanimate objects
Hospital disinfectant-registered for use in medical
facility
Alcohol, sodium hypochlorite-bleach, chlorine,
formaldehyde

30. 
Sterilization
A process of destroying all viable micro-
organisms including spores
Sterilizer-apparatus used to sterilize
medical devices and instruments by
directly exposing to sterilizing agents
Sterile-state of being free from all living
microorganisms

31. 
Antiseptic
A substance which destroys or inhibits the
growth of micro-organisms
Suitable to apply topically to living tissues
Asepsis-prevention of contact with
microorganism
Chlorhexidine, iodine

32. 
Sanitizer: agent that reduces the number
of bacterial contaminants to safe levels as
judged by public health requirements

33. 
Properties of an ideal disinfectant
Broad spectrum, fast acting
Active in presence of organic matter
Non-toxic to user and environment friendly
Should not corrode instruments
Antimicrobial layer on treated surfaces
Odourless, soluble and stable
Economical and easy to use

34. 
Types of Disinfection
Concurrent Disinfection
Terminal Disinfection
Pre-current (Prophylactic) Disinfection

35. 
Concurrent Disinfection
Measures for disinfection as soon as
possible:
afterdischarge of infectious materials
from the body of an infective person
aftersoiling of articles with infectious
discharges
disinfectionof vomit, urine, faeces,
clothes, hands, dressings, gloves etc.

36. 
Terminal Disinfection
Application of measures for disinfection
after the patient has been removed from a
hospital or by death or has ceased to be a
source of infection (It is now not practiced
commonly)
Terminal cleaning is considered adequate
along with airing and sunning of rooms,
furniture and bedding

37. 
Pre-current Disinfection
Prophylactic disinfection as:
Disinfection of water by chlorine
Hand washing
Pasteurization of milk

38. 
Disinfectant Agents
Natural Agents
Physical Agents
Chemical Agents

39. 
Natural Agents
Sunlight
Direct and continuous exposure to
sunlight is destructive to many organism
bedding, linen, furniture
Airing
Exposure to open air acts by drying or
evaporation of moisture which is lethal
to most bacteria

40. 
Physical Agents
Burning or Incineration
Contaminated dressing, rags, swabs etc.
Hot Air
Sterilizing articles such as syringes, swabs,
instruments
Boiling
Rolling boil for 5-10 minutes will kill
bacteria but not spores or viruses

41. 
Physical Agents
Autoclaving sterilizers which act at high
temperature (100 degC) and pressure are called
autoclaves.
Most effective sterilizer for absolute sterility of
gloves, syringes, instruments
Not suitable for plastics and sharp instruments
Ionizing radiation
Most effective sterilizer for dressing, needles,
instruments etc.
Very effective but very costly too

42. 
Chemical Agents
Phenol & related compounds:
Phenol, crude phenol, cresol, cresol
emulsions, chlorhexidine,
hexachlorphane, dettol(chloroxylenol)
Quaternary Ammonia compounds:
Cetrimide, savlon
Halogens & their compounds:
Bleaching powder, sodium hypochlorite,
halazonetablets, iodine, iodophors

43. 
Chemical Agents
Alcohols
Available evidence suggests that the most
effective skin antiseptics are alcoholic
solutions of chlorhexidineand iodine
Formaldehyde
Miscellaneous
Lime, ethylene oxide

44. 
Disinfection Procedures

45. 
Recommended Disinfection
Procedures
Faeces & Urine
Sputum
Room

46. 
Faeces & Urine Disinfection
Faeces & Urine should be collected in
impervious vessels
Disinfected by adding equal volume of one of
the disinfectantsand allowed to stand for 1-2
hours
Quicklime can also be used if recommended
one are not available

47. 
Faeces & Urine Disinfection

48. 
Sputum Disinfection
Best is to receive sputum in gauze or paper
handkerchiefs & destroy by burning
If amount is considerable (as in TB), it may
be disinfected by boiling or autoclaving for
20 minutes at 20 lbs. pressure

49. 
Sputum Disinfection
Patient may be asked to spit in a sputum
cup half filled with 5 per cent cresol
When cup is full, it is allowed to stand for
an hour and the contents may be emptied
and disposed off

50. 
Room Disinfection
Thorough cleaning, airing & exposure to direct
sunlightwhen possible for several hours
Floor & hard surfaces in the room should be
prohibited for 48 hours
For chemical disinfection, floor and hard
surfaces should be mopped or sprayed with
disinfectant

51. 
Room Disinfection
Chlorine preparations such as chlorinated lime
in concentrations that leave 25 ppm or more
of free chlorine
Formaldehyde solutions at a concentration of
1 % or more
Phenol disinfectants such as 2.5 % cresol
Solutions must remain in contact with surface for
at least 4 hours before final washing

52. 
Room Disinfection
Fumigationif required, the gas most commonly used
is formaldehyde
It may be generated by boiling commercial formalin
in 2 volumes of water in stainless steel vessel, over
an electric hot plate
There is vigorous boiling and liberation of
formaldehyde gas
Room is kept close for 6-12 hours to allow
disinfection

53. 
Medical students have a responsibility to
make every effort to minimize the spread
of infection and to encourage patients
and other health-care workers to actively
engage in practices that minimize the
spread of infection both in the
community, in the hospitals and clinics
What medical students
need to do?

54. 