public health 1 11111111111111111(1).ppt

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1. Public Health

2. Health
Definitions:
Persons are healthy when they are doing their activities with
no apparent symptoms of disease in them.
Or
According WHO: A state of complete physical, mental,
and social well-being and not merely the absence of disease
or infirmity.
The WHO definition envisages three specific
dimensions (physical, mental, and social) health, some
other dimensions like spiritual, emotional may also be
included.

3. Health
Physical health-is concerned with anatomical
integrity and physiological functioning of the body. It
means the ability to perform routine tasks without any
physical restriction.
Mental Health-is the ability to learn and think
clearly.
Social health-is the ability to make and maintain
acceptable interaction with other people
E.g. to celebrate during festivals; to mourn when a close
family member dies; to create and maintain friendship.

4. Health
Emotional health -is the ability of expressing
emotions in the appropriate way, for example to fear,
to be happy. It is related to mental health and includes
feelings.
Spiritual Health -Some people relate health with
religion; for others it has to do with personal values,
beliefs, principles and ways of achieving mental
satisfaction.

5. Public Health
Public health
Defined as the science and art of preventing diseases,
prolonging life, promoting health and efficiencies through
organized community effort. It is concerned with the
health of the whole population and the prevention of
disease from which it suffers.
It is also one of the efforts organized by society to protect,
promote, and restore the peoples’ health. It is the
combination of sciences, skills and beliefs that is directed
to the maintenance and improvement of the health of all
the people through collective social actions.

6. Key Terms in the definition:
A. Health Promotion:
is a key element in public health and is applicable in the
community, clinics or hospitals, and in all other service
settings. Raising awareness and informing people about
health and lifestyle factors that might put them at risk.
It seeks to increase involvement and control of the
individual and the community in their own health.
It acts to improve health and social welfare, and to
reduce specific determinants of diseases and risk
factors that adversely affect the health, well-being,
and productive capacities of an individual or society.

7. B. Prevention
Prevention refers to the goals of medicine that are to
promote, to preserve, and to restore health when it is
impaired, and to minimize suffering and distress
Primarily concerned with preventing physical, mental, and
emotional disease and injury, In addition to treating the Sick
and injured.
Three levels of prevention
Primary
Secondary
Tertiary

8. Prevention levels:
A. Primary B. secondary C. Tertiary
prevent the occurrence
of disease or injury.
i.e. Immunization
against infectious
diseases,
-Using safety
equipment to protect
workers in hazardous
occupations
-Erradication of
mosquito
vectors of malaria
early diagnosis and
management to prevent
complications from a
disease. It
includes Screening
programs in which people
with early, often
preclinical, manifestations
of disease are identified
steps to isolate cases and
treat or immunize
contacts to prevent further
epidemic outbreaks.
-involves activities directed
at the host but also at the
environment in order to
promote rehabilitation,
restoration, and maintenance
of maximum function after
the disease and its
complications have
stabilized.
-Providing a wheelchair,
special toilet facilities,
doors, ramps, and
transportation services for
paraplegics

9. Core activities in public health
1. Preventing epidemics
2. Protecting the environment, work place ,food and
water
3. Promoting healthy behavior
4. Monitoring the health status of the population
5. Mobilizing community action
6. Responding to disasters
7. Assuring the quality ,accessibility, and accountability of
medical care
8. Reaching to develop new insights and innovative
solutions
9. Leading the development of sound health policy and
Planning

10. MAJOR DISCIPLINES IN PUBLIC
HEALTH
Nutrition:is the science of food, the nutrients and
other substances, their action, interaction and balance
in relation to health and disease.
Reproductive health:is a state of complete physical,
mental and social being not only absence of disease or
infirmity, in all matters relating to reproductive system
and to its functions and process

11. Environmental Health: Identify specific biologic,
chemical, social and physical factors that represent
hazards to health or well-being and to modify the
environment in a manner that protects people from
harmful exposures. The principal components of
environmental health are water sanitation, waste
disposal.
Health Education

12. Epidemiology
forms the basis for public health action and unites
the public health professions. (epimeaning upon,
demosmeaning people, and logiameaning study).
Was originally applied to the study of outbreaks of
acute infectious diseases & defined as the science
of epidemics.
Epidemiology is the study of frequency,
distribution, and determinants of diseases and
other related states or events in specified
populations.

13. Epidemiologisthas
diverse backgrounds, including human and animal medicine,
microbiology, statistics, computer programming, toxicology and
entomology.
Role of epidemiologist:
Identity factors that cause disease
identify factors or conditions that can be used or modified to
prevent the occurrence or spread of disease
explain how and why diseases and epidemics occur
evaluate the effectiveness of vaccines and different forms of drug
therapy
establish a clinical diagnosis of disease
identify the health need of the community
evaluate the effectiveness of health programs
predict the future health needs of a population

14. The epidemiologic triangle
The
epidemiologic
triangle
Agent
Host
Inorderforadiseaseprocess
tooccur,theremustbea
uniquecombinationofevents:
aharmfulagentthatcomesinto
contactwithasusceptiblehost
intheproperenvironment.
Environement

15. Epidemiologic
triangle
Agent
Environment
Host
Biologic
Chemical
Physical
Biological
traits
Social
traits
Sex
Age
Race &
ethnic
Marital status
Lifestyle
Diet
Residence
Temperature
Moisture
Socioeconomic
state
Pollution

16. Health Economics: is concerned with the alternative
uses of resources in the health services sector.
Biostatistics is the application of statistics to
biological problems; application of statistics especially
to medical problems.
Health Service Management is getting people to
work harmoniously together and to make efficient use
of resources in order to achieve objectives.
Research

17. Demography is the study of population, especially
with reference to size and density, fertility, mortality,
growth, age distribution, migration, and the
interaction of all those with social and economic
conditions.

18. Spectrum of disease
describes the varied expression of illness in a population
& Include:
Infectious diseases :
Also known as transmissible diseases or communicable diseases.
Are clinically evident illness (with characteristic medical signs and
or symptoms resulting from the infection, presence and growth
of pathogenic biological agents in an individual host organism.
Achronic disease
is adiseasethat is persistent or otherwise long-lasting inits
effects. The term chronicis usually applied when thecourseof the
disease lasts for more than three months. Common chronic
diseases include arthritis,asthma,cancer,diabetesandAIDS.

19. Spectrum of disease
Epidemic disease: in this disease a harmful agent comes
into contact with a group of susceptible hosts in the proper
environment to establish a widespread occurrence. This
means sudden rise in the incidence rate of a disease.
Endemic disease: Habitual presence of a disease in a
particular geographical area e.g. Bilharzia in Egypt.
Pandemic disease: an epidemic disease occurring over a
wide geographic area (more than one nation)
Sporadic disease: occurrence of a disease at infrequent and
scattered cases of no great threat to the whole population.

20. Food &
Nutrition
Waste
Disposal
Water
Supply &
Sanitation
Environ-
-mental
Health
Family &
Social
Health
Mental
Health
Occupot-
-ional
diseases
Non-
infectious
diseases
Infectious
disease
Public
Health

21. Infectious diseases or Communicable
disease
Reservoir Mode of transmission Susceptible host
Human
(case or carrier)
Soil
e.g. Tetanus,
Gas gangreen,
anthrax
Animal
e.g. Brucella,
rabies, psittacosis
Droplet
(direct or Air born)
Food and water
(Intestinal
Infections)
Arthropods
(Biological Transmission)
Contact
Parentral or
transplacental
Animal Bite
Sex
Underlying
disease
Age
Immunity

22. A.Resevoir
I. Human reservoir
1) Case: may be clinical or subclinical.
2) Carrier: is a person who harbors the
microorganism and sheds it in absence of
clinical disease or symptoms.
Carriers are the most dangerous reservoir for
infections.

23. Types of carriers (according to;)
Type Duration Port of entery
1-Healthy
2-Incubatory
3-Convalescent
1-Temporary
2-Chronic
1-Respiratory
e.g. influenza.
2-Fecal (intestinal
carriers)
e.g. typhoid, dysentery
and cholera.
3-Blood
e.g. hepatitis and
AIDS.
4-Urinary or sexual
e.g. gonococcus and
AIDS

24. According to type:
Healthy carriers:person who sheds the microorganisms without having any
clinical manifestations of the disease.
Incubatory carriers:a person who sheds the microorganism (especially
last days of the incubation period) e.g. mumps, measles and diphtheria
Incubation Period: the time interval between the entry of the
microorganism and the appearance of the first symptoms of the
disease.
Convalscent carriers: person who still shed the microorganism
during convalescent period e.g. typhoid, dysentery and whooping
cough.
Convalescent period:The time interval between the
disappearance of the symptoms and the disappearance of the
microorganism from the host.

25. II. Animal reservoir
Animals or birds (cases or carriers) e.g. infection
with rabies, and Brucella, TB, Anthrax etc…from
animals and psittacosis & Q-fever from birds.
III. Soil reservoir
Soil is considered as a reservoir for agents causing
tetanus, gas gangrene and anthrax.
Both animal and soil reservoir are very difficult to
eradicate.

26. B. Mode of transmission
A) Droplet (Respiratory)
1-Direct droplet(sneezing, coughing or talking)
-Bacteria: Staphylococcus, Streptococcus, Pneumococcus, diphtheria, Meningococcus
, Bordetella(causing whooping cough), T.B., Haemophilus influenza,
Psitacosis, Q fever and Mycoplasma pneumonia.
-Virus: Influenza, mumps, measles, rubella and small pox.
2-Air borne:
-Droplet nuclei: dried residues of droplets e.g..T.B.
-Dust: due to droplets which settle down on floor e.g. T.B or psittacosis.

27. B) Food and water (Intestinal Infections)
Bacteria: typhoid, dysentery, cholera, food poisoning
Virus: hepatitis A and poliomyelitis
Parasites: Entamoeba.
C) Arthropods (Biological Transmission)
Fleas: plague and endemic typhus (Rickettsia typhi)
Mosquitoes: yellow fever and malaria.
Lice: epidemic relapsing fever (Borrelia recurrentis)
Tick: endemic relapsing fever (Borrelia duttoni)
Mites: transmit scrub fever (Rickettsia tsutsugamushi)

28. D) Contact
direct transfer through kissing or sexual contact
* Kissing: e.g. infectious mononucleosis (cytomegalovirus)
* Sexual contact: e.g.
Bacteria: gonorrhea, syphilis and lymphogranuloma venerum.
. Virus: herpes simplex type and AIDS.
E) Parentral or blood transfusion
hepatitis B, C and AIDS.
F) Animal Bite
-rabies.
G) Transplacental
-syphilis, AIDS, hepatitis B and rubella.

29. The Infection Process
organism must attach or adhere to host cells, usually
epithelial cells.
Organism multiply and spread directly through tissues
or via the lymphatic system to the bloodstream. This
infection (bacteremia) can be transient or persistent.
Organism can spread widely in the body through
blood and permits them to reach tissues particularly
suitable for their multiplication.

30. The Process of
Infection and Disease
4 distinct stages of clinical infections:
incubation period-time from initial contact with the
infectious agent to the appearance of first symptoms; agent
is multiplying but damage is insufficient to cause symptoms;
several hours to several years
prodromal stage–vague feelings of discomfort; nonspecific
complaints
period of invasion–multiplies at high levels, becomes well
established; more specific signs and symptoms
convalescent period–as person begins to respond to the
infection, symptoms decline

31. Patterns of infection:
Localized infection–microbes enters body and remains
confined to a specific tissue
Systemic infection–infection spreads to several sitesand
tissue fluids usually in the bloodstream
Focal infection–when infectious agent breaks loose from a
local infectionand is carried to other tissues
Mixed infection–several microbesgrow simultaneously at the
infection site -polymicrobial
Primary infection–initial infection
Secondary infection–another infectionby a different microbe
Acute infection–comes on rapidly, with severe but short-lived
effects
Chronic infections–progress and persist over a long periodof
time

32. Signs and Symptoms
Sign–objective evidence of disease as noted by an
observer
fever, septicemia, chest sounds, rash, leukocytosis,
antibodies
Symptom–subjective evidence of disease as
sensed by the patient
chills, pain, nausea, itching, headache. fatigue

33. Types of Communicable Diseases
1. Diseases controlled primarily by vaccination:
For example measles, mumps, rubella, pertussis,
tetanus diphtheria, poliomyelitis and Herpes zoster.
2-Sexually transmitted diseases (STDs):
For example syphilis, gonorrhea, AIDS, chlamydial
infections.
3-Diseases spread by close personal contact:
include acute respiratory infections, aseptic
meningitis, Herpes simplex, T.B., leprosy,
streptococcal diseases, trachoma and cytomegalovirus
infections.

34. Types of Communicable Diseases
(continu)
4-Diseases spread by food and water:
For example typhoid fever, shigellosis, cholera, amoebiasis,
giardiasis.
5-Nosocomial infections(infections occur in hospitals)
6-Diseases transmitted primarily by arthropod vectors:
e.g.: -arbovirus infection e.g. yellow fever (mosquito-borne)
-Rickettsia infections e.g. Q fever, epidemic typhus.
-Plague, malaria, Lyme disease, trypanosomiasis, leishmaniasis, filariasis.

35. Types of Communicable Diseases
(continu)
7-Zoonotic diseases (diseases transmitted by animals): These include:
Viral: Rabies. Bacteria: psittacosis, anthrax, brucellosis,
leptospirosis. Protozoa: toxoplasmosis.
Helminths: fascioliasis, trichinellosis, schistosomiasis.
8-Fungal infections:
e.g.: dermatophytes, candidiasis, etc.

36. Control of Communicable diseases
Agent/ Reservoir
Mode of
Transmission
Host
Chemotherapeutic agents
Disinfectants
Heat
Preservation temperature
Isolation or quarantine
Immunization
Eradication of infected animals
Good hygienic practice
Hand washing
Wearing protective apparel
Arthropod eradications
Proper waste disposal
Good health habits
(exercise, rest, balanced
diet)
-Chemoprophylaxis
(Chloroquine# malaeria,
INH # TB,
Tetracycline # Cholera
-Immunization
-Herd Immunity

37. Herd immunity
Herd immunityis a form of immunity that occurs when the vaccination
of a significant portion of a population (or herd) provides a measure of
protection for individuals who have not developed immunity.
This can effectively stop the spread of disease in the community. It is
particularly crucial for protecting people who cannot be vaccinated.
These include children who are too young to be vaccinated, people with
immune system problems, and those who are too ill to receive vaccines
(such as some cancer patients).
The spread of a communicable disease within a group based on the
proportions of susceptible and immune individuals in the group.
Epidemics or outbreaks of disease occur when the proportion of
susceptible individuals is high and disappear as the proportion of
immune individual increases.

38. Polio vaccine and Herd immunity
Polio vaccination is also important in the development ofherd immunity.
For polio to occur in a population, there needs to be an infecting
organism (poliovirus), a susceptible human population, and a cycle
oftransmission. Poliovirus is transmitted only through person-to-
person contact and the transmission cycle of polio is from one
infected person to another person susceptible to the disease, and so on.
If the vast majority of the population is immune to a particular agent,
the ability of thatpathogento infect another host is reduced; the cycle
of transmission is interrupted, and the pathogen cannot reproduce and
dies out. This concept, called community immunity or herd immunity,
is important to disease eradication, because it means that it is not
necessary to inoculate 100% of the population—a goal that is often
logistically very difficult—to achieve the desired result. If the number
of susceptible individuals can be reduced to a sufficiently small number
throughvaccination, then the pathogen will eventually die off

39. Polio vaccine and Herd immunity
When many hosts are vaccinated, especially simultaneously,
the transmission of wild virus is blocked, and the virus is
unable to find another susceptible individual to infect. Because
poliovirus can only survive for a short time in the
environment (a few weeks at room temperature, and a few
months at 0–8°C (32–46°F)) without a human host the virus
dies out.
Herd immunity is an important supplement to
vaccination. Among those individuals who receive oral
polio vaccine, only 95 percent will develop immunity.

40. Polio vaccine and Herd immunity
That means five of every 100 given the vaccine will not
develop any immunity and will be susceptible to developing
polio. According to the concepts of herd immunity this
population whom the vaccine fails, are still protected by the
immunity of those around them.
Herd immunity can only be achieved when vaccination levels
are high. It is estimated that 80–86 percent of individuals in a
population must be immune to polio for the susceptible
individuals to be protected by herd immunity.If routine
immunization were stopped, the number of unvaccinated,
susceptible individuals would soon exceed the capability of
herd immunity to protect them