1. بسم الله الرحمن الرحيم 1 Dr. Malik Muhammad Abdul Razzaq

2. Assistant Professor Department of Community Medicine Sheikh Zayed Medical College Rahim Yar Khan 2 Dr. Malik Muhammad Abdul Razzaq

3. CHAIN OF INFFECTON THE CHAIN OF INFFECTION 3 Dr. Malik Muhammad Abdul Razzaq

4. Agent factors It is a substance, living or non-living, or a force tangible or intangible, the excessive presence or relative lack of which may initiate or perpetuate a disease process. A disease may have a single agent, a number of independent alternative agents or a complex of two or more factors whose combined presence is essential for the development of the disease. 4 Dr. Malik Muhammad Abdul Razzaq

5. Types of Causative Agents Biological agents Nutrient agents Physical agents Chemical agents Mechanical agents Absence or insufficiency or excess of a factor necessary to health Social agents 5 Dr. Malik Muhammad Abdul Razzaq

6. Host factors Demographic : age, sex,ethnicity Biological: genetic factors, Biochemicals levels of blood, hormones, functions of organs. Social and economic: socio-economic status, education, occupation, stress, marital status, housing, etc. Lifestyle factors: personality traits, living habits, nutrition, physical exercise, use of alcohol, drugs and smoking etc. 6 Dr. Malik Muhammad Abdul Razzaq

7. Environmental factors All that which is external to the individual human host, living and non living and which he is in constant interaction. Physical Environment Biological Environment Psychosocial Environment. 7 Dr. Malik Muhammad Abdul Razzaq

8. Psychosocial Environment Those factors affecting personal health, health care and community wellbeing that stem from the psychosocial make up of individuals and structure and functions of social groups. Cultural values, customs, habits, beliefs Attitude, morals, religion, education Life style, Community Life, Health services Social & political Organization. 8 Dr. Malik Muhammad Abdul Razzaq

9. POSITIVE IMPACT Improve Health Provide opportunities Improve quality of Life NEGATIVE IMPACT: Poverty, Urbanization, Migration, Stressful Conditions, bereavement, desertion, loss of employment, handicapped child, anxiety, depression, Anger, frustration. 9 Dr. Malik Muhammad Abdul Razzaq

10. Risk factors An attribute or exposure that is significantly associated with the development of a disease A determinant that can be modified by intervention, thereby reducing the possibility of occurrence of a disease or other specified outcome. Non –Modifiable ( immutable) Age, Sex, Genetic Factors & ethnicity. Modifiable Factors ( mutable) Smoking, hypertension, elevated serum cholesterol, physical inactivity, obesity, etc.. 10 Dr. Malik Muhammad Abdul Razzaq

11. Risk Approach Something for all, but more for those in need - in proportion to the need" Therefore it is stated that risk factor is a proxy for need'- indicating the need for promotive and preventive health services. 11 Dr. Malik Muhammad Abdul Razzaq

12. Prominent Risk FactorsDiseases Risk Factors Heart disease Smoking, high blood Pressure, elevated serum cholesterol, diabetes, obesity, lack of exercise, type A personality Cancer Smoking, alcohol, solar radiation, ionizing radiation, work-site hazards, environmental pollution, medications, infectious agents, dietary factors. Stroke High blood pressure, elevated cholesterol, smoking. Motor vehicle accidents Alcohol, non-use of seat belts, speed, automobile design, roadway design Diabetes Obesity, diet Cirrhosis of liver Alcohol 12 Dr. Malik Muhammad Abdul Razzaq

13. “AT RISK GROUPS” Biological situation: - age: infants (low birth weight), toddlers, elderly - sex: females in the reproductive age period - physiological state: pregnancy, cholesterol level, high blood pressure - genetic factors : family history of genetic disorders - others: disease, physical functioning, unhealthy behavior Physical situation: - rural, urban slums - living conditions, overcrowding - environment: water supply, proximity to industries 13 Dr. Malik Muhammad Abdul Razzaq

14. “AT RISK GROUPS” Sociocultural situation: - social class - ethnic and cultural group - family disruption, education, housing - customs, habits and behaviour like smoking, lack of exercise, over-eating, drug addicts) - access to health services - lifestyles and attitudes 14 Dr. Malik Muhammad Abdul Razzaq

15. Disease Control An ongoing operation to reduce: i. The incidence of disease ii. The duration of disease iii. The risk of transmission. iv. The effects of infection, including both the physical and psychosocial complications v. The financial burden to the community. The disease “agent” is permitted to persist in the community at a level where it ceases to be a public health problem. 15 Dr. Malik Muhammad Abdul Razzaq

16. Disease Elimination Between control and eradication. Elimination is used to describe interruption of transmission of disease from large geographic regions or areas. 16 Dr. Malik Muhammad Abdul Razzaq

17. Disease Eradication Termination of all transmission of infection by extermination of the infectious agent from the whole world. Eradication is an absolute process. It is all or none phenomenon. 17 Dr. Malik Muhammad Abdul Razzaq

18. Monitoring The performance and analysis of routine measurements aimed at detecting changes in the environment or health status of population. The continuous oversight of activities to ensure that they are proceeding according to plan. 18 Dr. Malik Muhammad Abdul Razzaq

19. Surveillance The continuous scrutiny of the factors that determine the occurrence and distribution of disease and other conditions of ill – health. It includes the collection, analysis, interpretation and distribution of relevant data for action 19 Dr. Malik Muhammad Abdul Razzaq

20. Objectives To provide information about new and changing h. problemsTo provide information about new and changing h. problems To provide feed-back which may be expected to modify the policy and redefine objectives.To provide feed-back which may be expected to modify the policy and redefine objectives. Provide timely warning of public health disasters so that interventions can be mobilized Provide timely warning of public health disasters so that interventions can be mobilized 20 Dr. Malik Muhammad Abdul Razzaq

21. Iceberg of disease 21 Dr. Malik Muhammad Abdul Razzaq

22. LEVELS OF PREVENTION 22 Dr. Malik Muhammad Abdul Razzaq

23. 1. Primordial Prevention Prevention of emergence or development of risk factors in country or population groups in which they have not yet been appeared. Discourage to adapt harmful lifestyle. THROUGH:Individual education Mass education. 23 Dr. Malik Muhammad Abdul Razzaq

24. 2. PRIMARY PREVENTION An action taken prior to the onset of disease, which removes the possibility that disease will occur. Intervention in the pre-pathogenesis phase of a disease or H. problem, To promote general health To promote quality of life By 1: adapting specific measures. 2: Elimination/modification of risk factors STRATEGY: Population & High risk 24 Dr. Malik Muhammad Abdul Razzaq

25. 3.SECONDARY PREVENTION Action which halts the progress of a disease at its incipient stage and prevents complications. Early Diagnosis & Adequate treatment. To arrest the disease process Restore health by seeking unrecognized disease Prompt treatment before irreversible changes occur Reverse communicabilty of infectious disease. 25 Dr. Malik Muhammad Abdul Razzaq

26. 4. TERTIARY PREVENTION All measures available to reduce or limit impairment and disabilities, minimize sufferings and promote patient’s adjustment to irremediable conditions. intervention in late pathogenesis Intervention to limit disability 26 Dr. Malik Muhammad Abdul Razzaq

27. MODES OF INTERVENTION Any attempt to intervene or interrupt the usual sequence in the development of disease in man. 1. Health promotion 2. Specific protection 3. Early diagnosis & prompt treatment 4. Disability Limitation 5. Rehabilitation. 27 Dr. Malik Muhammad Abdul Razzaq

28. 1.HEALTH PROMOTION A process of enabling people to increase control over & to improve health. Health education Environmental modifications Nutritional interventions Life style & behavioural changes 28 Dr. Malik Muhammad Abdul Razzaq

29. HEALTH PROMOTION Health education Good standard of nutrition Attention to personality development Provision of good housing & recreation Good working conditions Marriage counseling Sex education Periodic selective examinations Genetics Environmental modifications 29 Dr. Malik Muhammad Abdul Razzaq

30. 2.SPECIFIC PROTECTION USE OF SPECIFIC IMMUNIZATIONS USE OF SPECIFIC NUTRIENTS CHEMOPROPHYLAXIS PROTECTION AGAINST OCCUP.HAZARDS PROTECTION FROM CARCINOGENS AVOIDANCE OF ALLERGENS USE OF ENVIRONMENTAL SANITATION CONTROL OF QUALITY PRODUCTS PROTECTION FROM ACCIDENTS ATTENTION TO PERSONAL HYGIENE 30 Dr. Malik Muhammad Abdul Razzaq

31. 3.EARLY DIAGNOSIS & PROMPT TRAETMENT To intercept the disease process To cure and prevent disease process To prevent secondary cases (spread) To prevent complications and sequelae To shorten period of disability To reduce mortality For better prognosis (Critically important in chronic diseases) 31 Dr. Malik Muhammad Abdul Razzaq

32. 3.EARLY DIAGNOSIS & PROMPT TRAETMENT Case finding measures Screening surveys Selective examinations Mass treatment approach Total mass approach Juvenile mass treatment selective mass treatment 32 Dr. Malik Muhammad Abdul Razzaq

33. Disability limitation To prevent or halt the transition of the disease process from impairment to handicap. Adequate treatment to arrest disease process To prevent further complications/disability Provision of facilities to limit disability and to prevent death. Disease → Impairment → Disability → Handicap 33 Dr. Malik Muhammad Abdul Razzaq

34. IMPAIRMENT: Any loss or abnormality of psychological, physiological or anatomical structure or function. e.g. Loss of foot Defective vision Mental retardation IMPAIRMENT visible or invisible Temporary or permanent Progressive or regressive 34 Dr. Malik Muhammad Abdul Razzaq

35. DISABILITY Inability to carry out certain activities “Any restriction or lack of ability to perform an activity within the range considered normal for a human being”. 35 Dr. Malik Muhammad Abdul Razzaq

36. HANDICAP A disadvantage for a given individual, resulting from an impairment or a disability, that limits or prevents the fulfillment of a role that is normal for that individual (depending on age, sex, and social and cultural factors). 36 Dr. Malik Muhammad Abdul Razzaq

37. Concept of disability AccidentDisease Loss of footImpairment Cannot walkDisability UnemployedHandicap 37 Dr. Malik Muhammad Abdul Razzaq

38. REHABILITATION 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. 38 Dr. Malik Muhammad Abdul Razzaq

39. Rehabilitation a. Medical rehabilitation – restoration of function b. Vocational rehabilitation – restoration of the capacity to earn a livelihood. c. Social rehabilitation – restoration of family and social relationships d. Psychological rehabilitation – restoration of personal dignity and confidence. “to live and work within the limits of disability but to his capacity”. 39 Dr. Malik Muhammad Abdul Razzaq

40. Rehabilitation Establishing schools for blind Provision of aids for crippled Reconstructive surgery Community facilities to retrain disabled to use remaining capacities Graded exercises Changes in profession Modification of life & full employment as possible Education of industry to utilize rehabilitated Use of sheltered colony 40 Dr. Malik Muhammad Abdul Razzaq

41. INFECTION The entry and development or multiplication of an infectious agent in the body of man or animals. An infection does not always cause illness. Body responds as-immune response -disease. 41 Dr. Malik Muhammad Abdul Razzaq

42. CONTAMINATION The presence of an infectious agent on a body surface; also on or in clothes, beddings, toys, surgical instruments or dressings, or other inanimate articles or substances including water, milk and food. 42 Dr. Malik Muhammad Abdul Razzaq

43. POLLUTION The presence of offensive material is called pollution. It is distinct from contamination. 43 Dr. Malik Muhammad Abdul Razzaq

44. INFESTATION It is a state of having a parasite in or on the body which includes arthropods or animal parasites. The lodgement, development and reproduction of arthropods on the surface of the body of man or animal, in the clothings etc. 44 Dr. Malik Muhammad Abdul Razzaq

45. HOST A person or animal that affords subsistence or lodgement of an infectious agent under natural conditions. An obligate host: means the only host. An intermediate host: in which the parasite is in a larval or asexual state. (Secondary)) Definitive Host: in which the parasite attains maturity or passes its sexual stage. (Primary) A transport host: a carrier in which the organism remains alive but does not undergo development. 45 Dr. Malik Muhammad Abdul Razzaq

46. INFECTIOUS DISEASE A clinically manifest disease of man or animal that results from an infection. It is a state of disorder that results from an infection by bacteria or viruses. e.g., cholera, Diphtheria, Tuberculosis, measles, Chickenpox. 46 Dr. Malik Muhammad Abdul Razzaq

47. CONTAGIOUS DISEASE A disease that is transmitted through contact. e.g. scabies, trachoma, STD and leprosy. 47 Dr. Malik Muhammad Abdul Razzaq

48. COMMUNICABLE DISEASE An illness due to a specific infectious agent or its toxic products capable of being transmitted directly or indirectly from man to man, animal to animal or from environment to man or animal. 48 Dr. Malik Muhammad Abdul Razzaq

49. EPIDEMIC Unusual occurrence of a disease or health related problem and health related behaviour in a community or region clearly in excess of expected occurrence.. Disease affecting a large number of persons within a short space of time. 49 Dr. Malik Muhammad Abdul Razzaq

50. ENDEMIC It refers to the constant presence of a disease or an infectious agent within a given geographic area or population group. When the number of susceptible and immune persons are almost equal, the disease continues to smoulder in a community and is always present in the community. 50 Dr. Malik Muhammad Abdul Razzaq

51. HYPERENDEMIC It expresses that the disease is constantly present at a high incidence or prevalence and affects all age groups equally. 51 Dr. Malik Muhammad Abdul Razzaq

52. HOLOENDEMIC It is the high level of infection beginning in early life and affecting most of the child population. 52 Dr. Malik Muhammad Abdul Razzaq

53. SPORADIC The cases occur irregularly, haphazardly from time to time and generally infrequently. The cases are so few and separated that they show little or no connection with each other nor a common source of infection. 53 Dr. Malik Muhammad Abdul Razzaq

54. PANDEMIC An epidemic usually affecting a large proportion of the population, occurring over a large geographic area such as nation, continent or the whole world. A world wide epidemic is a pandemic. When the susceptibility of the whole country or the world is increased for a particular organism e.g. influenza Pandemic of 1918-19. 54 Dr. Malik Muhammad Abdul Razzaq

55. EXOTIC When a disease is not usually present in a locality but is introduced form abroad, it is called Exotic. 55 Dr. Malik Muhammad Abdul Razzaq

56. ZOONOSIS An infection or infectious disease transmissible under normal conditions from vertebrate animals to man. e.g. rabies, plague, bovine tuberculosis, Anthrax, brucellosis, endemic typhus etc. 56 Dr. Malik Muhammad Abdul Razzaq

57. EPIZOOTIC An outbreak ( epidemic) of disease in an animal population. e.g. anthrax, brucellosis, rabies. 57 Dr. Malik Muhammad Abdul Razzaq

58. NOSOCOMIAL INFECTION Hospital acquired An infection originating in a patient while in a hospital or health care facility. A disorder associated with being in a hospital. It may be unrelated with the primary condition. May appear after discharge. Infections to the staff of the facility. 58 Dr. Malik Muhammad Abdul Razzaq

59. OPPORTUNISTIC INFECTION It is an infection by an organism that takes the opportunity provided by the defect in host defense to infect the host and cause disease. Opportunistic infections are common in AIDS E.g. Herpes, cytomegalovirus,toxoplasma 59 Dr. Malik Muhammad Abdul Razzaq

60. IATROGENIC DISEASE Physician induced disease An adverse consequence of a preventive, diagnostic or therapeutic regimen or procedure that causes impairment, handicap, disability or death resulting from a physician’s professional activity. Can prolong hospital stay Requires special treatment Threaten life. 60 Dr. Malik Muhammad Abdul Razzaq

61. HOST A person or animal that affords subsistence or lodgement of an infectious agent under natural conditions. An obligate host: means the only host. An intermediate host: in which the parasite is in a larval or asexual state. (Secondary)) Definitive Host: in which the parasite attains maturity or passes its sexual stage. (Primary) A transport host: a carrier in which the organism remains alive but does not undergo development. 61 Dr. Malik Muhammad Abdul Razzaq

62. RESERVOIR Any person, animal, soil, arthropod, plant or substance in which an infectious agent lives and multiplies, on which depends primarily for survival and can be transmitted to a susceptible host. Reservoir is a natural habitat in which an organism metabolises and replicates. 62 Dr. Malik Muhammad Abdul Razzaq

63. SOURCE A PERSON, ANIMAL, OBJECT, OR SUBSTANCE FROM WHICH AN INFECTIOUS AGENT PASSES OR IS DESSIMINATED TO THE HOST. 63 Dr. Malik Muhammad Abdul Razzaq

64. HUMAN RESERVOIR CASES: A person in the population or study group identified as having the particular disease, health disorder or condition under investigation. clinical, biochemical, laboratory tests Clinical cases Sub clinical cases Latent infection: host does not shed infectious agent which lies dormant within the host without symptoms. 64 Dr. Malik Muhammad Abdul Razzaq

65. HUMAN RESERVOIR CARRIER: An infected person or animal that harbours a specific infectious agent in the absence of discernible clinical disease and serves as a potential source of infection for others. Carriers are less infectious Carriers are more dangerous than cases. 65 Dr. Malik Muhammad Abdul Razzaq

66. CARRIER A Type (a) Incubatory (b) Convalescent ( c) Healthy B Duration (a) Temporary (b) Chronic C Portal of Exit (a) Urinary (b) Intestinal (c) Respiratory 66 Dr. Malik Muhammad Abdul Razzaq

67. MODES OF TRANSMISSION 67 Dr. Malik Muhammad Abdul Razzaq

68. DIRECT TRANSMISSION 1. Direct Contact 2. Droplet Infection 3. Contact with soil 4. Inoculation into skin or mucosa 5. Transplacental (vertical) 68 Dr. Malik Muhammad Abdul Razzaq

69. INDIRECT TRANSMISSION 1. Vehicle-borne (water, food, milk, fruits) 2. Vector-borne a Mechanical Transmission b Biological Transmission i. Propagative ii. Cyclo – Propagative iii. Cyclo Developmental 69 Dr. Malik Muhammad Abdul Razzaq

70. INDIRECT TRANSMISSION 3. Air – Borne a Droplet nuclei b Dust 4. Fomite – borne 5. Unclean hands and fingers 70 Dr. Malik Muhammad Abdul Razzaq

71. Incubation Period The time interval between invasion by an infectious agent and appearance of the first sign or symptom of the disease. Median Incubation Period: The time required for 50 per cent of the cases to occur following exposure.. 71 Dr. Malik Muhammad Abdul Razzaq

72. USES OF INCUBATION PERIOD a. Tracing the source of infection and contacts b. Period of Surveillance c. Immunization d. Identification of point source or propagated epidemics e. Prognosis 72 Dr. Malik Muhammad Abdul Razzaq

73. 73 Dr. Malik Muhammad Abdul Razzaq