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By
Yasmin Essam Khalil
Supervised by
Prof Dr. Mona Aboserea
ZAGAZIG UNIVERSITY
General Epidemiology of communicable
and no...
Epidemiology
It is medical science that involves the study of the incidence and
distribution of diseases in large populati...
EPIDEMIOLOGY OF COMMUNICABLE
DISEASES
Communicable diseases are diseases transmitted from one
case to another. There is a ...
Epidemiologic triad
Disease is the result of forces within a dynamic system
which is called an epidemiologic triad
THE INFECTIOUS CYCLE or CHAIN
1- Agent • Protozoa, unicellular parasites e.g. amoebae
• Metazoa, multicellular parasites e.g ascaris and ancylostoma
• F...
The starting point for the occurrence of a communicable disease is the
existence of a reservoir or source of infection.
Th...
I- Human Reservoir
A- Cases :
are those individuals who are suffering from the disease.
They may be
• Typical cases showin...
B- Carriers  a person who is harboring the organism
(allows its multiplication inside his body) without showing signs
and...
II- Animals reservoir
Diseases that can be transmitted under natural conditions
from vertebrate animals to humans are call...
III- Reservoir in non-living things
Soil can also act as reservoir of infection (e.g. soil may harbor agents
that cause te...
4- Modes of transmission
 Droplet or air borne method: either directly from reservoir to host
via droplets during kissing...
 Arthropod borne method: either biological transmission i.e mul
tiplication or development of new stages of the organism ...
6-Host factors
5-Portal of Entry
the route the agent uses to get into the new host. In general, the portal
of entry is sim...
Factors affecting host immunity:
1- Age: extremes of age have low immunity.
2- Sex: some diseases affect females more as p...
7- Environmental conditions: unsanitary water and waste
disposal, presence of vectors and rodents, ill ventilation, increa...
Herd immunity
(Immunity of the community)
 Describes the immunity level that is present in a population group
.
 Herd im...
Types of immunity
1. Non-specific: mechanisms that prevent entrance of agents
to the body: - e.g.
a) Intact skin
b) Cough,...
b) Humeral immunity:
• Circulating antibodies are proteins that inactivate specific antigens
or organisms and prevent repl...
I. Naturally Acquired Immunity:
I- Natural active immunity
After infection (manifest disease or subclinical infections), t...
II. Artificially acquired immunity
1. Artificial acquired active immunity:
Immunity is induced by immunization by vaccine ...
Causes of failure of Active Immunization:
spoiled vaccine due to change in its optimal temperature (most va
ccines need co...
2. Artificial acquired passive immunity
Seroprophylaxis ready-made immunoglobulin given for rapid
protection after exposu...
7- Incubation period (I.P)
The time interval between contact with an agent and the first clinical
evidence of the disease....
The incubation period varies individually according to:
Defense mechanism: the ability to react against agent invasion in ...
8-Clinical picture and complication
Differs from disease to another and from one case to another also.
This item will be d...
 Epidemic Widespread of infection, unexpected increase in number
of already present infection in certain area in short p...
Types of Epidemic
• Common source epidemic
1- All individual are exposed to a common pathogen or noxious
agent
2- The mode of transmission i...
• Point source epidemic
1- All susceptible individual are exposed to specific pathogen at
one point of time
2- Point sourc...
• Propagative source epidemic
1- Serial transmission as the pathogen is transmitted from
person to person .
2- Mode of tra...
Epidemic investigation
Definition
Epidemic investigation is a set of procedures used to identify the cause
i.e. the infect...
Steps of epidemic investigation
1. Verify the diagnosis or causes:
-Careful analysis of the initial reports.
- Confirm dia...
4. Develop hypotheses to explain the occurrence of the epidemic.
5. Test the hypothesis
6. Identification of susceptible p...
Prevention
I-Primordial Prevention: health promotion
Prevention of emergence or development of Risk Factors.
Prevention fr...
III-Secondary Prevention: = disease control
Halt the progress of a disease at its incipient phase ‫اولية‬ ‫.مرحلة‬
Early d...
2- ERADICATION: Termination of all transmission of infection by
extermination of the infectious agent through surveillance...
IV-Tertiary Prevention:
Intervention in the late Pathogenesis Phase.
Reduce impairments, minimize disabilities & suffering...
Handicap: Any disadvantage that prevents one from fulfilling his
role considered normal.
Rehabilitation has been defined...
PREVENTION OF COMMUNICABLE
DISEASES
I- Primary prevention "Health promotion and specific protection".
 Sanitary environme...
 Health education of the public:
Health awareness
Proper knowledge, attitude and practice related to health, with special...
Chemoprophylaxis
Administration of antimicrobial drugs for specific protection of certain
infectious diseases to prevent d...
 International preventive measures
1-International regulations are followed by different countries to
prevent transmissio...
II- Secondary prevention: "Early diagnosis and prompt treatment"
Control measures to be taken for existing infectious dise...
Control of human reservoir:
A- Control of cases:
1- Case finding.
2- Notification
Cases of definite or suspected diagnosis...
4- Disinfection:
Disinfection is the process of destroying pathogenic organisms outside
the body
a) Concurrent disinfectio...
B- Control of carriers:
Carriers may be difficult to control. It is important to do pre-employment
and periodic medical ex...
Eradication of animal reservoir if applicable.
Control of farm and pet animals to prevent or minimize animal-animal
or ani...
 Eradication of infectious disease: is getting rid of causative
organism and consequently of disease: no reported cases a...
IV- Tertiary Prevention "Disability
Limitation and Rehabilitation"
Their purpose is to reduce or eliminate long-term impai...
Vaccination VS Immunization
• Vaccination is the term used for getting a vaccine, that is,
actually getting the injection ...
• Immunization refers to the process of both getting the
vaccine and becoming immune to the disease following
vaccination
...
Epidemiology of non communicable diseases
Definition
**Non communicable diseases are non-infectious and non-transmissible
between persons. Mostly they are chronic d...
Reasons of the increasing prevalence of NCDs:
(1) The demographic transition: The decrease in mortality resulted in
increa...
(4)The multi-factorial nature of the risk factors for the non-com
municable diseases:
 Compared to communicable diseases ...
Panel for demonstrating the demographic, epidemiologic and
nutrition transition
(5) Migration of population across different cultures:
The individuals who migrate from low risk culture (e.g .rural areas...
(7) Environmental changes:
The increase in the level of physical and chemical air pollution is
associated with high preval...
(10) Limited use of scientific progress in management of NCDs:
There are rapid and successful achievements in the science ...
Almost all the non communicable diseases have unknown cause, but
they have some related risk factors.
They can be classifi...
Identified five important risk factors for non-communicable disease in
the top ten leading risks to health. These are :
1....
Prevention of non communicable diseases
1- Primary prevention:
• health promotion
• health education
• adopting healthy li...
• Social activity to relief stress;
• no smoking;
• avoiding drinking alcohol or taking drugs;
• living in a healthy envir...
2- Secondary prevention:
Early detection of cases and proper management which give better
prognosis.
Screening tests can b...
3- Tertiary prevention:
To rehabilitate the complicated cases as in osteoporosis, osteoarthritis,
late cancer cases and co...
Egypt National Multi-sectoral Action Plan for
Prevention and Control of Non communicable Diseases 2018-2022
(Egypt MAP-NCD)
Egypt National STEPwise Survey for
Non-communicable Diseases Risk Factors Report 2017
Target population: National househol...
General epidemiology
General epidemiology
General epidemiology
General epidemiology
General epidemiology
General epidemiology
General epidemiology
General epidemiology
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General epidemiology

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GENERAL EPIDEMIOLOGY

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General epidemiology

  1. 1. By Yasmin Essam Khalil Supervised by Prof Dr. Mona Aboserea ZAGAZIG UNIVERSITY General Epidemiology of communicable and non communicable diseases
  2. 2. Epidemiology It is medical science that involves the study of the incidence and distribution of diseases in large populations and the conditions influencing the spread and severity of disease. Epidemiology is the study of the distribution and determinants of health-related states or events (including disease), and the application of this study to the control of diseases and other health problems.
  3. 3. EPIDEMIOLOGY OF COMMUNICABLE DISEASES Communicable diseases are diseases transmitted from one case to another. There is a cycle for transmission of infection from one host to another. What is the aim of studying epidemiology of communicable diseases ? To put preventive and control measures, limit their spread in the community and limit their complications in cases.
  4. 4. Epidemiologic triad Disease is the result of forces within a dynamic system which is called an epidemiologic triad
  5. 5. THE INFECTIOUS CYCLE or CHAIN
  6. 6. 1- Agent • Protozoa, unicellular parasites e.g. amoebae • Metazoa, multicellular parasites e.g ascaris and ancylostoma • Fungi e.g tinea captis • Bacteria e.g. gram (+), gram (-) bacilli, coccus e.g Enteric fever, tuberculosis • Rickettsia e.g rocky mountain fever, typhus • Viruses e.g hepatitis Exposure to an agent does not always cause clinical symptomsThere are some factors: 1- Natural characteristic of the agent e.g. reproduction, metabolism, motility, and production of toxin. 2- Characteristic of the agent related to infection in human:- Infectivity The ability of an organism to invade and infect a host. Pathogenicity Ability to cause disease. Virulence Ability to cause serious complications and or death Antigenicity Ability to stimulate host production of antibody
  7. 7. The starting point for the occurrence of a communicable disease is the existence of a reservoir or source of infection. The source of infection  "is the immediate person or object fro m which the infectious agent passes to the host. Reservoir: The natural habitat, in which an agent lives, grows and multiplies. 2-Source and reservoir N.B: The source of infection may be a part of the reservoir or not e.g. food poisoning (the reservoir is the carrier who contami nate the food, while the source of infection is the food itself).
  8. 8. I- Human Reservoir A- Cases : are those individuals who are suffering from the disease. They may be • Typical cases showing the typical manifestation of the disease and their level of severity may range from being mild to moderate to severe, or they may be • Atypical i.e. does not show the typical manifestation of diseases • Subclinical or in apparent which can pass undiagnosed.
  9. 9. B- Carriers  a person who is harboring the organism (allows its multiplication inside his body) without showing signs and symptoms. And is capable of transmitting the disease to other person. N.B the carriers are considered to be the most dangerous source of infection followed by the subclinical or in apparent infection then the atypical cases and finally the typical cases Types of Carriers 1. Incubatory carriers who shed the infectious agent during the incubation period of disease before they become symptomatic. 2. Convalescent carriers  who continue to shed the infectious agent during the period of convalescence. 3. Contact carriers  during care for case. 4. Chronic carriers who continue to harbor an agent for indefinite periods.
  10. 10. II- Animals reservoir Diseases that can be transmitted under natural conditions from vertebrate animals to humans are called zoonosis (e.g. rabies, yellow fever, plague, anthrax, brucellosis). The famous animal reservoirs are cat, dog, horse, cattle, poultry and rodents
  11. 11. III- Reservoir in non-living things Soil can also act as reservoir of infection (e.g. soil may harbor agents that cause tetanus and anthrax). 3- Portal of exit Path by which an agent leaves its human or animal source host. e.g. 1- Respiratory tract e.g. influenza virus 2- Genitourinary tract e.g. sexually transmittal diseases 3- Alimentary tract e.g. hepatitis A virus (HAV) 4- Blood e.g. hepatitis B virus (HBV) 5- In-utro transmission e.g. rubella, cytomegalovirus.
  12. 12. 4- Modes of transmission  Droplet or air borne method: either directly from reservoir to host via droplets during kissing, sneezing, cough, spitting (short distance transmission). Or indirectly through droplet nuclei (suspended air particles or dust that transmit agents to far places) or through conta minated articles as cups, spoon, fomites.  Food borne method: either directly from host feces to mouth via w ater, hands, food or indirectly through flies, cockroach, dust.  Contact method (by skin and mucous membrane): direct contact be tween case and new host, contact with infected animal. Or indirect t hrough clothes, fomites, dust, water pool. Infection by contaminated syringes occurs through skin penetration. Therefore it can be consid ered as one of the contact routes of transmission. the way in which the agent is transferred to a new host
  13. 13.  Arthropod borne method: either biological transmission i.e mul tiplication or development of new stages of the organism occur inside the vector as in malaria, filarial. No infection occurs without this biological transformation. The other method is mechanical i.e the vec tor just carry the organism from the case to new host as flies carrying typhoid bacilli from patient's feces to food.  From mother to infant during pregnancy: intrauterine infection as German measles, malaria, syphilis, AIDS.
  14. 14. 6-Host factors 5-Portal of Entry the route the agent uses to get into the new host. In general, the portal of entry is similar to the portal of exit e.g.  Respiratory tract  Ingestion  Dermal  Blood borne  Mucous membranes the intrinsic factors that influence an individual's exposure, susceptibility, or response to a causative agent. There is a balance between immunity of host and virulence of organism. For infection to occur, the virulence must exceed host immunity. If the individual has high immunity he can defend any infection
  15. 15. Factors affecting host immunity: 1- Age: extremes of age have low immunity. 2- Sex: some diseases affect females more as poliomyelitis. 3- Pregnancy: more severe manifestations of infection occur in preg nant than non-pregnant of the same age. 4- Nutrition: malnutrition is associated with increased infection. 5- Trauma and fatigue or stress increase the incidence and severity of infection. 6- Occupation: certain occupations are more prone to infection as medical staff and laboratory workers.
  16. 16. 7- Environmental conditions: unsanitary water and waste disposal, presence of vectors and rodents, ill ventilation, increased temperature enhances growth of certain organisms. 8- Education and culture of people affecting their sanitary habits, health consciousness and practice towards infection. 9- Socio-economic standard that affects sanitary housing conditions, good nutrition. 10-Vaccination, subclinical / clinical infections provide level of immunity may be lifelong
  17. 17. Herd immunity (Immunity of the community)  Describes the immunity level that is present in a population group .  Herd immunity provides an immunological barrier to the spread of diseases in the community.  The higher the herd immunity is  the higher the power to defense of an epidemic occurrence in the community.  Herd immunity may be acquired after frequent mass vaccinations.
  18. 18. Types of immunity 1. Non-specific: mechanisms that prevent entrance of agents to the body: - e.g. a) Intact skin b) Cough, sneezing reflexes c) Gastric juices d) Normal bacterial flora e) Secretions as saliva, tears. 2. Specific: The immune system consists of cell-mediated immunity and circulating antibodies. a) Cell-mediated immunity is responsible for delayed hypersensitivity and the regulation of anti-body production, e.g. patients with acquired i mmune deficiency syndrome (AIDS) have abnormalities in the T-cell su b populations and, consequently, are infected by common organisms tha t typically do not cause disease in healthy people.
  19. 19. b) Humeral immunity: • Circulating antibodies are proteins that inactivate specific antigens or organisms and prevent replication in the body. • Antibodies are disease–specific (e.g. the measles antibody only protects against measles). • They are either naturally acquired or artificially acquired.
  20. 20. I. Naturally Acquired Immunity: I- Natural active immunity After infection (manifest disease or subclinical infections), the body for ms antibodies against that infection. Some infections give solid immunit y as measles, chicken pox and others give short time immunity as influe nza. II- Natural passive immunity (maternal immunity)  antibodies fr om mothers during pregnancy are transmitted to infant. It depends on th e diseases the mother had exposed to before pregnancy to form antibodi es. No cellular immunity is transmitted because of placental barriers. An tibodies also are present in colostrum breast milk secreted on the first da ys after labor.
  21. 21. II. Artificially acquired immunity 1. Artificial acquired active immunity: Immunity is induced by immunization by vaccine which stimulates t he body to form immunoglobulin. Duration of immunity depends on the type of vaccine. a) Live vaccine (as small pox) and live attenuated vaccine (as MM R and measles)  give lifelong immunity. b) Killed vaccine (contains killed agents but still retain their antigeni city) as typhoid, pertussis  give short time or low level of immun ity. c) Vaccine may be prepared from The whole organism: as polio and measles The capsule of organism: polysaccharide vaccine as meningitis Surface antigen of virus as hepatitis B vaccine Toxin secreted by the organism : as diphtheria and tetanus
  22. 22. Causes of failure of Active Immunization: spoiled vaccine due to change in its optimal temperature (most va ccines need cold chain in transportation and storage ) Vaccination during the first 6 months of life when maternal immu nity is still present and interferes with action of vaccine.
  23. 23. 2. Artificial acquired passive immunity Seroprophylaxis ready-made immunoglobulin given for rapid protection after exposure to infection. The body has no role in immunity It is given either for prevention or attenuation of disease severity. It usually gives short duration of immunity. Immunoglobulins or Antitoxins are either of animal origin as tetanus, di phtheria and gas gangrene antitoxins or of human origin prepared from plasma of actively immunized persons as rabies serum. Chemoprophylaxis: administration of antimicrobial drug before exposure or just after exposure to prevent occurrence of disease (not for treatment). Penicillin is used for prevention of rheumatic fever, tetracyclines for cholera, INH for tuberculosis, rifampicin for meningitis Chemoprophylaxis has disadvantages: expensive, side effects of drug, not used for long period, short immunity (immunity is present while dru g is taken only). Drug resistance after its community use for long periods.
  24. 24. 7- Incubation period (I.P) The time interval between contact with an agent and the first clinical evidence of the disease. It depends on: Portal of entry (defense mechanism). The ability of multiplication (infectivity). Number of agents. Level of antibody in the host. Importance of IP: Tracing the source of infection and contact Period of surveillance Immunization Identification of point source or propagated epidemics Prognosis e.g. in rabies, and tetanus, the shorter the IP is, the worse the prognosis of disease.
  25. 25. The incubation period varies individually according to: Defense mechanism: the ability to react against agent invasion in the body. It consist of :- a) The external defense mechanism (Cough, Sneeze reflex, Gastric acid, Vomit reflex, Skin, Tears). b) The internal defense mechanism: cellular and humeral immunity. If the external defense mechanism cannot eliminate the agent the internal defense mechanism will continue the defense mechanism process by: Inflammation Isolation by fibrocytes Macrophage phagocytosis Antibody reaction
  26. 26. 8-Clinical picture and complication Differs from disease to another and from one case to another also. This item will be discussed in details in Medicine. Types of spread of communicable diseases:- Sporadic cases infected cases have no common source of infection . They spread all over far away areas not related to each other. Outbreak  spread of infection in confined place as school or camp. Usually there is common source for infection, if controlled the incidence of infection decreases.
  27. 27.  Epidemic Widespread of infection, unexpected increase in number of already present infection in certain area in short period. Or it is introduction of new infection to the country never shown that disease before as SARS, Avian flu. Endemic :constant presence of disease within a given geographic area or population group. Pandemic : spread of infection all over the world or in many countries e.g. avian flu, Aids. Epizootic: Spread of Zoonotic disease in large scale among animals e.g. cow mad disease.
  28. 28. Types of Epidemic
  29. 29. • Common source epidemic 1- All individual are exposed to a common pathogen or noxious agent 2- The mode of transmission is indirect because • The agent is vehicle borne (contact through fomites, food, air ,water ) • 2ry Host to host transmission (direct) is rare 3-By examining the epidemic curve: • Fewest number of cases become apparent after minimum incubation period • Largest number peak occur by the end of usual incubation period (from the point of exposure to the midline of the curve) • The shape is typical unimodal shape of common source epidemic
  30. 30. • Point source epidemic 1- All susceptible individual are exposed to specific pathogen at one point of time 2- Point source epidemic is a subcategory of common source epidemic in which common exposure to the offending pathogen or agent is both brief and simultaneous 3- By examining the curve • Very explosive increase in the number of cases over a short period of time after exposure to the agent • One incubation period ,so the apex is much sharper and the decline in the number of cases is more rapid than in typical common source curve • 2ry transmission is rarely seen in point source epidemic as with common source epidemic
  31. 31. • Propagative source epidemic 1- Serial transmission as the pathogen is transmitted from person to person . 2- Mode of transmission may be direct (direct human contact or direct aerosolized respiratory droplets ) or may be indirect ( vector borne – airborne) 3- Individual immunogenicity and herd immunity play an important role in propagative disease transmission 4- The curve shows : • Initial rise in the number of cases that is less explosive than in a point source epidemic • Successive generations of secondary infection produce a poly- modal distribution conforming to several generations of incubation periods
  32. 32. Epidemic investigation Definition Epidemic investigation is a set of procedures used to identify the cause i.e. the infectious agent, responsible for the disease. Value 1. It is also used to identify the people affected, the circumstances and mode of spread of the disease, and other relevant factors involved in propagating the epidemic. 2. Epidemic investigation is a challenging task for health workers. 3. The main purpose of epidemic investigation is to control the spread of the disease before it causes more deaths and illness.
  33. 33. Steps of epidemic investigation 1. Verify the diagnosis or causes: -Careful analysis of the initial reports. - Confirm diagnosis by performing clinical and laboratory studies. -Putting the criteria for case definition. 2. Establish the existence of an epidemic: By comparing the current level (incidence) with the past level of the disease in that locality and population. 3. Description of the epidemic as regard time, place and person: - By plotting the cases by time of onset (Epidemic curve). - By plotting the cases by location (Spot map). - Collect data on the age, sex, etc. of the cases.
  34. 34. 4. Develop hypotheses to explain the occurrence of the epidemic. 5. Test the hypothesis 6. Identification of susceptible population. 7. Management of the epidemic. 8. Formulation of the report and communicate findings and recommendation to higher levels in the health system, community leaders and other local stakeholders
  35. 35. Prevention I-Primordial Prevention: health promotion Prevention of emergence or development of Risk Factors. Prevention from Risk Factors. Discouraging harmful life styles. Encouraging or promoting healthy eating habits (to prevent obesity in childhood) . Not focused to specific disease II-Primary Prevention: Action taken prior to the onset of the disease Pre-pathogenesis Phase of a certain disease. Immunization - Use of specific Nutrients Chemoprophylaxis - Protection against Occupational Hazards Avoidance of Allergens - Control of specific hazards in general environment - Control of Consumer Product Quality & Safety
  36. 36. III-Secondary Prevention: = disease control Halt the progress of a disease at its incipient phase ‫اولية‬ ‫.مرحلة‬ Early diagnosis & Adequate medical treatment. DISEASE CONTROL: aimed at reducing: The incidence of disease. The duration of disease and the consequently the risk of transm ission. Physical and psychological complication. The financial burden to the community. CONCEPT OF CONTROL 1- ELIMINATION: Reduction of case transmission to a predetermined very low level or interruption in transmission. E.g . measles, polio, leprosy from the large geographic region or area
  37. 37. 2- ERADICATION: Termination of all transmission of infection by extermination of the infectious agent through surveillance and containment. “All or none phenomenon”. E.g. Small pox 3- MONITORING: Defined as “the performance and analysis of routine measurement aimed at detecting changes in the environment or health status of population.” e.g. growth monitoring of child, Monitoring of air pollution, monitoring of water quality……. etc. 4- SURVEILLANCE: Defined as “the continuous analysis of the factors that determine the occurrence and distribution of disease and other conditions of ill health.” e.g. Poliomyelitis surveillance programme of WHO
  38. 38. IV-Tertiary Prevention: Intervention in the late Pathogenesis Phase. Reduce impairments, minimize disabilities & suffering. DISABILITY LIMITATIONS The Objective is to prevent or halt the transition of the disease proc ess from impairment to handicap.  Sequence of events leading to disability & handicap: Disease → Impairment → Disability→ Handicap Impairment: Loss or abnormality of psychological, physiological/ anatomical structure or function. Disability: Any restriction or lack of ability to perform an activity in a manner considered normal for one’s age, sex, etc.
  39. 39. Handicap: Any disadvantage that prevents one from fulfilling his role considered normal. Rehabilitation has been defined as the ‘combined and coordinated use of medical, social, educational and vocational measures for training and retraining the individual to the highest possible level of functional ability” Areas of concern in rehabilitation: Medical Rehabilitation Occupational Rehabilitation Social Rehabilitation Psychological Rehabilitation
  40. 40. PREVENTION OF COMMUNICABLE DISEASES I- Primary prevention "Health promotion and specific protection".  Sanitary environment: The environment would be free of: Vehicles of infection: polluted air, water, milk, food, soil Vector of disease: infection transmitting arthropods Rodents(including rats): potential reservoir of many infections Infected animal reservoir (Stray dogs and cats) Components of sanitary environment:  Proper town, village or district planning and design  Good housing with suitable ventilation  Sanitary collection and disposal of waste  Food and milk sanitation  Eradication or control of insects, rodents, stray dogs and cats
  41. 41.  Health education of the public: Health awareness Proper knowledge, attitude and practice related to health, with special consideration of life style, habits and behavior  Health promotion of the public: Health promotion can be achieved by fulfilling requirements of health: Physical, mental and social health Prenatal, natal and post natal care  Specific prevention: Specific prevention is specific protection of man against causative age nts of infectious diseases by immunization (active and passive) and chemoprophylaxis
  42. 42. Chemoprophylaxis Administration of antimicrobial drugs for specific protection of certain infectious diseases to prevent development of disease and may be carrier state. Limitation of chemoprophylaxis: a) Cost: extensive use of antimicrobial may be costly compared to expe cted potential benefit b) Adverse effects of drugs c) Development of drug resistant strains d) Provided protection is temporary, for short period. Chemoprophylaxis may be the basic preventive measure of many disea ses including: Rheumatic fever, Meningococcal meningitis, Cholera, plague, Tuberculosis, Ophthalmia neonatorum
  43. 43.  International preventive measures 1-International regulations are followed by different countries to prevent transmission of certain infectious diseases called quarantinable diseases in between countries. At present quarantine measures are taken for cholera, yellow fever and plague. 2-Quarantine measures are taken for certain animals coming from endemic or infected areas e.g Monkey for yellow fever, Cattle for rift valley fever 3- Imported goods: For raw wool, shaving brushes. Authorized disinfection certificate is needed 4- Means of transportation: de rating certificate for ships in plague and disinfection of planes coming from yellow fever endemic areas
  44. 44. II- Secondary prevention: "Early diagnosis and prompt treatment" Control measures to be taken for existing infectious disease with the following objectives: Case finding: detection and diagnosis of cases Management of cases and preventing complications and sequelae of disease Measures for contacts and protecting susceptible Preventing or minimizing spread of disease in involved community or group.
  45. 45. Control of human reservoir: A- Control of cases: 1- Case finding. 2- Notification Cases of definite or suspected diagnosis must be notified to local heal th office Value of notification:  To take preventive and control measures  To help tracing sources and channels of infection in outbreaks  To collect significant statistical data 3- Isolation Cases of infectious diseases must be isolated either at home, hospital or special place according to nature of disease Value of isolation:  To stop activity and movement of case in the community  To protect the case from risk of secondary infection
  46. 46. 4- Disinfection: Disinfection is the process of destroying pathogenic organisms outside the body a) Concurrent disinfection is carried out during course of disease b) Terminal disinfection 5- Treatment many communicable diseases have been treated by effective drugs. The object of treatment is to kill the infectious agent When it still in the reservoir, i.e. before it disseminated. Treatment reduce the communicability of disease, cut short the duration of illness and prevent the development of secondary cases. 6- Release Patient discharge or the formal ending of inpatient care
  47. 47. B- Control of carriers: Carriers may be difficult to control. It is important to do pre-employment and periodic medical examination of certain occupational groups e.g food handlers, medical personnel and personnel serving children C- Control measures for contacts: Enlistment: a special list of contacts Examination: for case finding Not to be exposed to isolated case Surveillance, segregation or isolation according to disease Surveillance: contacts are put under supervision for incubation period of disease meanwhile, they can perform their activities Segregation: contacts are excluded from school or work but not isolated e.g measles, enterica and diphtheria Isolation: contacts of following diseases are isolated: Cholera in non-endemic areas Pneumonic plague Pneumonic anthrax Immunization or chemoprophylaxis
  48. 48. Eradication of animal reservoir if applicable. Control of farm and pet animals to prevent or minimize animal-animal or animal man transmission of infection through sanitary raising, feeding and veterinary care. Community control measures Epidemiological study and investigation to trace sources and channels of infection Drastic control measures to be taken if necessary e.g closing schools  Surveillance: Surveillance is an ongoing systemic collection, analysis, interpretation and dissemination of health data Control of animal reservoir
  49. 49.  Eradication of infectious disease: is getting rid of causative organism and consequently of disease: no reported cases and no reservoir of infection.  Elimination of disease: means that existing endemic infectious disease is so controlled to reach the level of no reported cases while causative agent is not necessarily eliminated.
  50. 50. IV- Tertiary Prevention "Disability Limitation and Rehabilitation" Their purpose is to reduce or eliminate long-term impairments and disabilities, minimize suffering, optimize function, prevent further deterioration of cases, to help complicated cases to cope with their handicapped condition.
  51. 51. Vaccination VS Immunization • Vaccination is the term used for getting a vaccine, that is, actually getting the injection or taking an oral vaccine dose • The US (CDC) defines a vaccine as "A product that stimulates a p erson’s immune system to produce immunity to a specific diseas e, protecting the person from that disease. Vaccines are usua lly administered through needle injections, but can also be adminis tered by mouth or sprayed into the nose.“ • Vaccination is the process of getting a vaccine into the body or "T he act of introducing a vaccine into the body to produce immunity to a specific disease." A vaccine is what initiates the immunizatio n process.
  52. 52. • Immunization refers to the process of both getting the vaccine and becoming immune to the disease following vaccination • According to the (WHO), "Immunization is the process whereb y a person is made immune or resistant to an infectious dis ease, typically by the administration of a vaccine. • Vaccines stimulate the body’s own immune system to protect t he person against subsequent infection or disease.“ • A person becomes immune to a disease when the body has be en exposed to it either through illness or vaccination/immunization. The immune system develops antibodies to the disease so that it cannot make you sick again. Immunization, therefore, describes the actual changes your body goes through after receiving a vaccine.
  53. 53. Epidemiology of non communicable diseases
  54. 54. Definition **Non communicable diseases are non-infectious and non-transmissible between persons. Mostly they are chronic diseases of long duration and slow progression which require chronic care management. They represent about 63% of all deaths and one of the leading causes of mortality according to World Health Organization (WHO) reports. Nearly 80% of these NCD deaths (29 million) occurred in low- and middle-income countries. The leading causes of NCD deaths in 2008 were: • cardiovascular diseases (17 million deaths representing 48% of NCD deaths • cancers (7.6 million, or 21% of NCD deaths); • respiratory diseases, including asthma and chronic obstructive pulmonary disease (COPD), (4.2 million). • Diabetes caused an additional 1.3 million deaths.
  55. 55. Reasons of the increasing prevalence of NCDs: (1) The demographic transition: The decrease in mortality resulted in increase in the life expectancy with subsequent increase in the proportion of the elderly populations. NCDs are usually associated with aging. (2) The epidemiologic transition: There is shift from mortality from communicable diseases (due to the use immunization and antibiotic use etc.) to NCDs which have chronic nature due to specific genetic, environmental and behavioral risk factors. (3) Nutritional Transition: There has been shift from famines to increased production and consumption of food. However, there is another large shift in the pattern of nutrition to a diet high in total fat, sugar and other refined carbohydrates and low in polyunsaturated fatty acids and fibers. At the same time there is increase in sedentary life . Such pattern resulted in increasing the prevalence of obesity and subsequent degenerative NCDs.
  56. 56. (4)The multi-factorial nature of the risk factors for the non-com municable diseases:  Compared to communicable diseases are difficult to identifying the specific cause-effect relationship.  The multiplicity of the risk factors associated with specific NCDs limit the opportunities to have specific intervention for prevention and control.  The type of risk factors are difficult to be controlled by medical technology (in communicable diseases , immunization and antibiotics are effective in prevention and control of diseases)  The risk factors are related to genetic, environmental, culture and behavior which represent a challenging issue to public health programs.
  57. 57. Panel for demonstrating the demographic, epidemiologic and nutrition transition
  58. 58. (5) Migration of population across different cultures: The individuals who migrate from low risk culture (e.g .rural areas) to high risk culture (e.g. Urban areas ) follow the life style of the new culture and demonstrate increased risk for NCDs. (6) International communication: International communication, multinational business and new food technologies have resulted in introduction of new life-style and new food products in the communities which have risks for NCDs. Communication through the mass media∕ satellites∕ internet, overseas travel, and international food marketing; facilitate the introduction of different concepts and dietary pattern which predispose to exposure to the risk factors of NCDs. Adolescents and youth are population segments who are exposed to such modernization in concepts and behavior. Consequently, the exposure to the risk of NCDs early in the life cycle will result in development of large cohort with health problems during adulthood and older age.
  59. 59. (7) Environmental changes: The increase in the level of physical and chemical air pollution is associated with high prevalence of NCDs. (8) Epidemiology of the NCDs differs across the countries: Due to differences in the prevalence of the different risk factors for NCDs (genetic, environmental, cultural and behavioral) across countries, there are limitations to use the universal information in any country. Public health specialists in each country should have specific surveillance system for the different non communicable diseases (e.g. countries in which people use spicy food have the problem of peptic ulcers and stomach neoplasm). (9) Epidemiology of NCDs is changing all the time: Some countries succeeded in improving the pattern of some NCDs (i.e. reduction in the incidence of coronary heart diseases through extensive anti- smoking programs).
  60. 60. (10) Limited use of scientific progress in management of NCDs: There are rapid and successful achievements in the science of risk detection, use of medication and technologies to prevent and control NCDs. However, in the developing countries high cost of NCDs prevention and control programs is challenging.
  61. 61. Almost all the non communicable diseases have unknown cause, but they have some related risk factors. They can be classified into: non modifiable and modifiable risk factors. A. Non modifiable risk factors: include genetics, age, sex, and race. These risk factors cannot be prevented. B. Modifiable risk factors: include smoking, alcoholism, unhealthy diet, exposure to environmental pollution, physical inactivity and stress. Other factors associated with higher risk of NCDs include a person's economic and social conditions, also known as the "social determinants of health." The modification of these risk factors can prevent or delay the occurre nce and complications of the chronic diseases. Common risk factors of (NCDs)
  62. 62. Identified five important risk factors for non-communicable disease in the top ten leading risks to health. These are : 1. raised blood pressure, 2. raised cholesterol level, 3. tobacco use, 4. alcohol consumption, and 5. overweight with insufficient physical activity. World Health organization global status Report 2 014
  63. 63. Prevention of non communicable diseases 1- Primary prevention: • health promotion • health education • adopting healthy life style (balanced diet and physical activity). • Eating balanced diet; eating more fruits and vegetables, eating less meat, fat, sugar and salt, and keeping weight within the normal range are important preventive measures. • practicing physical exercise as a routine fixed duty along with getting sufficient time for rest and sleep can be very helpful for preventing much NCDs.
  64. 64. • Social activity to relief stress; • no smoking; • avoiding drinking alcohol or taking drugs; • living in a healthy environment free of pollutants have important preventive roles. • Enhancing the role of laws and governance reform in preventing NCDs and their risk factors, improving access to NCD treatments, and addressing the social impacts of illness (e.g. Imposing and increasing taxes on tobacco to reduce demand, Smoking bans in public places, including workplaces, public transport and restaurants, Improving food labeling to encourage healthier choices, etc.)
  65. 65. 2- Secondary prevention: Early detection of cases and proper management which give better prognosis. Screening tests can be used for at risk groups for early detection. For example: 1. Blood pressure measurement for detection of hypertension (adults aged 40 years or older ) 2. Random blood sugar level for detection of diabetes (type 2 diabetes in adults 40 to 70 years of age who are overweight or obese and repeating testing every three years if results are normal 3. Cervical smear for detection of cancer cervix( in women age 21 to 65 years with cytology (Pap smear) every 3 years)
  66. 66. 3- Tertiary prevention: To rehabilitate the complicated cases as in osteoporosis, osteoarthritis, late cancer cases and complicated diabetes. 4. mammography or self examination of breast for detection of cancer breast ( from the age of 40 years old) 5. Alfa fetoprotein for detection of cancer liver (For people at higher risk of liver cancer due to cirrhosis OR chronic hepatitis B infection even without cirrhosis) every 6 to 12 months
  67. 67. Egypt National Multi-sectoral Action Plan for Prevention and Control of Non communicable Diseases 2018-2022 (Egypt MAP-NCD)
  68. 68. Egypt National STEPwise Survey for Non-communicable Diseases Risk Factors Report 2017 Target population: National household survey on persons aged 15-69 years old Sample size : 6680 households participated in the survey out of 7200 HH (94.3% response rate) Conducted by: Ministry of Health and population , control agency for public mobilization and statistics, World Health organization
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GENERAL EPIDEMIOLOGY

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