Public Health and infectious disease prevention discusses the history and concepts of public health including social medicine, community health, and achievements in public health such as vaccination programs. It also covers challenges like emerging infectious diseases and inequality. Infectious disease prevention strategies are discussed including vaccination, sanitation, and health education. Herd immunity is described as resistance to disease when a large proportion of a group is immune. Major infectious diseases causing death are identified as respiratory infections, HIV/AIDS, diarrheal diseases, tuberculosis, and malaria.

1. Public Health and infectious
disease prevention
Carlos Amade, MD

2. Content
• History of public health
• Social Medicine
• Community health and community
healt
• Achievements of public health
• Challenges of public health
• Infectious disease prevention
• Bibliography

3. Health is central to our lives
Health is a state of complete
physical, mental and social well-
being and not merely the absence
of disease or infirmity.
WHO, June 1946

4. Health belief: Amulet ‘protection’ against
cholera (France)

5. Conception of public health involving, politics,
medical and social sciences "Die Medicin ist eine sociale
Wissenschaft“ (Medicine is a social science and politics
is nothing else but medicine on a large scale). Rudolf
Vichow, Berlin mid 1800s

6. The Health Crisis: Origins Of Modern
Public Health

7. Rapid concentrations of population
which overwhelm water supply,
sanitation and housing
Civic protest against water pollution
(England 1830s)

8. Environmental, health and equity
issues
World’s first major public health legislation:
1848 (Edwin Chadwick, England)

9. New industrial way of life, dangerous
work, transport, pollution, accidents, food
adulteration, etc.

10. -Migration and break up of social networks
-State modernization held back by elites, yet
emergence of civil society

11. What is public health?
• Action by society to protect and promote
the health of everyone
• Involves science, evidence, art, politics
and imagination
• Requires partnerships and the
involvement of the population
• Requires knowledge, skills, motivation
and commitment
• Requires leadership and co-operation,

12. Concept of Public Health
“…the science and art of preventing
disease, prolonging life, and promoting
physical health and efficiency, through
organized community efforts, for the
sanitation of environment, the control of
community infections, the education of the
individual in the principles of personal
hygiene, the organization of medical and
nursing service for early detection and
preventive treatment of disease, and
development of the social machinery

13. Summarized concept of P.H.
The science and art of preventing
disease, promoting health and
prolonging life through organized
efforts of society.

14. Elements in the concept
• Collective responsibility
• Prime role of the state in promoting and
protecting the people health
• Partnership with the population served
• Emphasis on prevention
• Recognizing socioeconomic determinants
• Identifying and dealing with risk factors
• Multidisciplinary basis of action

15. Early names of Public Health
• Preventive medicine
• Social medicine
• Community medicine
• Community health
Now they are dimensions of Public Health

16. The dimensions of Public Health
Public Health
Social
Medicine
Preventive
Medicine
Community
Medicine
Community
Health

17. Preventive medicine
• Prevention is better than cure
• Encompasses both the care of
individual patients, and public health
practice
• Initially only for healthy people
(vaccination, nutrition,…)
• Then early diagnosis
• And now includes treatment of sick

18. Four (early three) levels of prevention

20. Social Medicine
• The poor die young

21. Social Medicine
• Social status linked to health of
individuals and community
• “The existing inequality in the health
status of people between developed and
developing countries as well as within
countries is politically, socially and
economically unacceptable and is,
therefore, of common concern of all

22. Rainbow of health determinants
• Source: Dahlgren G and Whitehead M (1991) Policies and strategies to promote social equity in
health. Stockholm, Institute for Futures Studies

24. Assumptions of Social Medicine
Health
birthright
state
(country)
development
education
social factors
begins at
home
poverty

25. Community Health
Services that aim to protect the community
Sanitation
Vector control
Health education
Water supply,….

26. Community Medicine
• Health Services provided at
community level
Now it is Primary Health Care

27. Modern Public Health
• Multidisciplinary
• Multisectorial
• Evidence-based
• Equity oriented

28. Public Health Clinical Medicine
Focus Populations Individuals
Ethics Public service Personal
Emphasis Disease prevention
and health
promotion for the
whole community
Disease diagnosis, treatment,
and care for the individual
patient
Paradigm Interventions aimed
at the environment,
human behavior and
lifestyle, medical care
Emphasis on medical care
concerns major threats to the
health of
populations;
Biological sciences central,
stimulated by needs of patient

29. What has public health achieved?
Ten Great Public Health Achievements -- United
States, 1900-1999 (according to US CDC)
• Vaccination
• Motor-vehicle safety
• Safer workplaces
• Control of infectious diseases
• Decline in deaths from coronary heart disease
and stroke
• Safer and healthier foods
• Healthier mothers and babies
• Family planning
• Fluoridation of drinking water
• Recognition of tobacco use as a health hazard

30. Great Public Health Achievements in
Europe 1900-2000?
• Extended life largely free of disease –
healthier children, healthier old age
• Family planning and reproductive rights
for women
• Cleaner air in cities
• Better, less crowded housing
• Safer workplaces and work processes
• Reduction of infectious diseases
• Safer and healthier range of foods
•…. ?

31. Africa???

32. Challenges of public health
• Resurgent infectious diseases and new
infectious diseases
• New avoidable chronic diseases (NCDs)
• Impact of
globalization, industrialization, urbanization
and population change on determinants of
health and ecology.
• Inequality and growth of socially excluded
groups
• Role of anti-health forces –
tobacco, alcohol, processed food, ‘culture

33. Infectious Disease and public
health:

34. Classification of Diseases & Health Problems
Organ or Organ System
– i.e., heart disease, kidney disease, respiratory
infection
Causative Agent
– Biological Agents
– Chemical Agents
– Physical Agents
Communicable vs Non communicable
Acute vs Chronic
–Peak symptoms within 3 months (acute) or
longer than 3 months (chronic)

35. Classification of Infectious Disease
• By duration
– Acute – develops and runs its course quickly.
– Chronic – develops more slowly and is usually less
severe, but may persist for a long, indefinite period of
time.
– Latent – characterized by periods of no symptoms
between outbreaks of illness.
• By location
– Local – confined to a specific area of the body.
– Systemic – a generalized illness that infects most of
the body with pathogens distributed widely in tissues.
• By timing
– Primary – initial infection in a previously healthy
person.

36. Infectious (communicable) disease
Is caused by transmission of a specific
pathogenic agent to a susceptible host.

37. Robin Cochran-Dirksen (Many slides from
BioEdOnline Baylor Christine Herrmann
PhD)
Infectious Diseases - Definitions
• Disease – a pathological condition of body
parts or tissues characterized by an
identifiable group of signs and symptoms.
• Infectious disease – disease caused by an
infectious agent such as a bacterium, virus,
protozoan, or fungus that can be passed on to
others.
• Infection – occurs when an infectious agent
enters the body and begins to reproduce; may
or may not lead to disease.
• Pathogen – an infectious agent that causes
disease.

38. Robin Cochran-Dirksen (Many slides from
BioEdOnline Baylor Christine Herrmann
PhD)
Infectious Disease Agents
• Most infectious agents that cause disease are
microscopic in size and thus, are called
microbes or microorganisms.
• Different groups of agents that cause disease
are:
– Bacteria
– Viruses
– Protozoa (Protists)
– Fungi
– Helminths

39. Infections do not arise in a vacuum

40. Factors That May Increase Risk of Human Disease
Host Factors Agent Factors Environment factors
Host Characteristics Types of Agents and Examples Environmental Factors
Age Biologic Temperature
Sex Bacteria, viruses Humidity
Race Chemical Altitude
Religion Poison, alcohol, smoke Crowding
Customs Physical Housing
Occupation Trauma, radiation, fire Neighborhood
Genetic profile Nutritional Water
Marital status Lack, excess Milk
Family background Food
Previous diseases Radiation
Immune status Air pollution
Noise

41. Modes of disease transmission
• Direct
– Person-to-person
contact
• Indirect
– Common vehicle
• (1) Single exposure
• (2) Multiple exposures
• (3) Continuous exposure
– Vector, vehicle, air

42. Transmission

43. Contagious diseases
• Without an intervening vector or vehicle

44. Robin Cochran-Dirksen (Many slides from
BioEdOnline Baylor Christine Herrmann
PhD)
Phases of Infectious Disease
• Incubation period – time between
infection and the appearance of signs and
symptoms.
• Prodromal phase – mild, nonspecific
symptoms that signal onset of some
diseases.
• Clinical phase – a person experiences
typical signs and symptoms of disease.
• Decline phase - subsidence of
symptoms.
• Recovery phase – symptoms have

46. Robin Cochran-Dirksen (Many slides from
BioEdOnline Baylor Christine Herrmann
PhD)
Related Terms
• Endemic/Enzootic: The constant
presence of a disease or infectious agent
within a given geographic area.
• Epidemic/Epizootic: The occurrence in
an area of a disease or illness in excess of
what may be expected on the basis of past
experience for a given population (in the
case of a new disease, any occurrence
may be considered "epidemic").
• Pandemic/Panzootic: A worldwide
epidemic affecting an exceptionally high
proportion of the global population.

48. The burden of communicable disease
• Communicable diseases account for 14.2 million
deaths each year
• Most in low-income settings
 Acute respiratory infections (3.76 million)
 HIV/AIDS (2.8 million)
 Diarrhoeal diseases (1.7 million)
 Tuberculosis (1.6 million)
 Malaria (1 million)
 Measles (0.8 million)

49. The burden of communicable disease

50. Infectious disease are threats to human security and
health systems
 Pose an acute threat to individual health
 Have the potential to threaten collective human
Security
 Low-income countries continue to deal with the
problems of communicable diseases, deaths due to
chronic diseases are rapidly increasing, especially in
urban settings

51. The challenge of infectious
diseases
• 20 well-known diseases - TB, malaria, and
cholera - have further spread since 1973, often in
more virulent and drug-resistant forms.
• Plus at least 30 previously unknown disease
agents identified since 1973, including HIV, Ebola,
hepatitis C, and Nipah virus, for which no cures
are available.
• HIV/AIDS and TB likely to account for the
overwhelming majority of deaths from infectious
diseases in developing countries by 2020.

56. HIV/AIDS
• 40 million people in the world infected with
HIV.
• In 2011, 4 million became infected with
HIV, and 3 million died of the disease.
• That is 8,000 deaths every day.
• 6 million are in immediate need of AIDS
treatment.

57. HIV, 2012 (WHO)

58. HIV, 2012 (WHO)

59. Malaria protected population

60. Malaria and drug resistance

61. Infectious disease prevention and
control
• Prevention
– Includes individual, clinical, or personal health
services such as immunizations, screening for
high blood pressure and follow-up services, or
the use of Pap smears to detect the precursors
to cancer of the cervix.
• Protection
– Includes the activities of organizations, both
public and private, to reduce exposure to
hazards such as polluted water, contaminated
food, traffic accidents, mosquitoes, or use of

62. Primary Prevention of communicable
diseases
Community actions
• Chlorination of the
water supply,
• Inspection of
restaurants,
• Immunization
programs that reach
all citizens,
• Maintenance of a
well-functioning
sewer system,
• Proper disposal of
solid waste
• Control of vectors
Personal/Individual
action
• Hand washing,
• Proper cooking of
foods,
• Adequate clothing and
housing,
• Use of condoms,
• Obtaining all of the
available immunizations
against specific
diseases

63. Secondary Prevention of communicable
diseases
Community effort
• Includes measures taken to
control or limit the extend
of a disease outbreak
 Maintaining records of
cases and compliance with
regulations requiring the
reporting of notifiable
diseases
 Investigating cases and
contacts, those who may
have become infected
through contact with cases
Individual effort
• Self-diagnosis and self-treatment
with nonprescription medications
or home remedies
• Diagnosis and treatment with an
antibiotic or other physician-
prescribed medicine

64. Occasionally, secondary disease
control measures may include
isolation or quarantime
Further measures may include
disinfection and mass treatment
with antibiotics

65. Tertiary Prevention of communicable
diseases
• Physical therapy
• In some cases, such as paralytic polio,
return to normal activity may not be
possible, even with extensive physical
therapy
• At the community level, proper removal
of infected items such as clothing,
disinfection, and burial of the dead.
• Tertiary prevention may also involve the
reapplication of primary and secondary

66. Herd Immunity
• Resistance of a group
of people to an
attack by a disease to
which a large
proportion of the
members of the
group are immune.

67. Herd immunity

68. Bibliography
• Bonita Epidemiology
• Gordis Epidemiology
• Harvard University, School of Public Health
(Online)
• John Hopkins University (Online)
• Short textbook of Public Health
• WHO

69. Thank you