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1. 3/28/2025 1 Blue Nile College Department of Nursing Module Title: Communicable disease control For Level IV Nursing By Tewodros T .(BSc Nursing ) Gondar, Ethiopia Mar, 2025 Teddy

2. 3/28/2025 2 Course syllabus Teddy Module Title: Communicable disease control Credit hour : 4 Course instructor: Tewodros T. Email address:teddyteshome173 @gmail.com

3. Course Description October,04,2024 Teddy 3 This learning guide introduces the fundamental concepts and skills necessary to Communicable disease control This module covers unit of competency of Communicable disease control among the national occupational standard in health .

4. 3/28/2025 4 Teddy Teaching method Interactive presentation Group discussion Group assignment and presentation Reading assignment Teaching Aids Printed materials LCD projectors Teaching method and material

5. 3/28/2025 5 Attendance : this course will involve numerous discussion and class activities students are expected to attend all classes Assignments : students must do given assignments on time Late assignment submission will not be accepted Cheating/plagiarism : Students must do their own work Cheating or Plagiarism will result in disqualification of the result Course Policy Teddy

6. 3/28/2025 Teddy 6 Assessment Continuous Institute Assessment Result (100%/LO) Test1…………………………..........…………. 7 0% Test 2…………………….……………………… 7 0% Test 3………………………………..………….. 7 0% Test 4……………………………………………… 7 0% Industry Assessment Result ………30% Average Total-----------------------------100% Grading system- Based on the college’s grading policy Course Policy….

7. 3/28/2025 7 Teddy Module units Diseases Prevention And Control Common Communicable Diseases Common Neglected Tropical Disease Perform Disease Surveillance

8. 3/28/2025 Teddy 8 Chapter one: Diseases Prevention And Control

9. What is disease? Disease : is a state of discomfort in which the normal functioning of the body is disturbed (e.g. Malaria, typhoid, chickenpox). Diseases: can be classified according to two major dimensions. time course & cause . Time course : classified as acute (characterized by a rapid onset and a short duration), and chronic disease (characterized by prolonged duration). 9 Overview of Communicable Disease 3/28/2025 Teddy

10. Overview cont ‘d Based on the cause , broadly categorized as Infectious or communicable disease : caused by living parasitic organisms such as viruses, bacteria, parasitic worms, insects, etc.) which is transmit from one person to the other. Non-communicable disease : caused by something other than a living parasitic organism) which is not spread from one person to another. 10 3/28/2025 Teddy

11. Relevant Terms to communicable diseases Infection – the entry and development or multiplication of an infectious agent in the body of human beings or animals Infestation – the lodgment, development and reproduction or arthropods on the surface of the body or in clothes Host – the person or animal that affords subsistence or lodgment to an infectious agent under natural conditions 11 3/28/2025 Teddy

12. Cont’d……. Infectious disease – a clinically manifest disease of a man or animal resulting from an infection Contagious disease – a disease that is transmitted through contact Communicable disease – an illness due to a specific infectious agents or its toxic products capable of being directly or indirectly transmitted from man to man, animal to animal or from environment to man or animal 12 3/28/2025 Teddy

13. Cont’d….. Epidemic – the unusual occurrence of disease in a community or region, specific health related behavior or events clearly in excess of expected occurrence Endemic – constant presence of a disease or infectious agent within a given geographic area or population group; without importation from outside 13 3/28/2025 Teddy

14. cont’d….. Sporadic – cases occur irregularly, haphazardly from time to time and generally infrequent eg polio, tetanus, herpes zoster Pandemic – an epidemic affecting a large proportion of the population occurring over a wide geographic area Zoonosis – an infection transmissible under natural conditions from vertebrate animals to man 14 3/28/2025 Teddy

15. Cont’d….. Nosocomial (hospital acquired)infection – infection originating in a patient while in hospital or other health care facility Opportunistic infection – an infection by organisms that take the opportunity of defect in the host defense to infect the host and cause disease Iatrogenic disease – any untoward or adverse consequence of preventive, diagnostic or therapeutic regimen or procedure that causes impairment, handicap, disability or death resulting from physicians professional activity or from the professional activity of other health professional 15 3/28/2025 Teddy

16. Monitoring – continuous oversight of activities to ensure that they are proceeding according to plan Eradication – termination of infection by extermination of the infectious agent through surveillance and containment but the infectious agent is present in the lab.. Control – ongoing operation aimed at reducing incidence, duration and effects of disease Extinction –eradication of infectious agent including in the lab… 16 3/28/2025 Teddy

17. Natural history of a communicable disease 3/28/2025 Teddy 17 The natural history of a communicable disease refers to the sequence of events that happen one after another, over a period of time, in a person who is not receiving treatment. Recognizing these events helps you understand how particular interventions at different stages could prevent or control the disease. Events that occur in the natural history of a communicable disease are grouped into four stages: exposure, infection, infectious disease, and outcome .

18. Stages for disease development 1.Stage of susceptibility (stage of exposure) The disease has not yet developed but the presence of risk factor increase the probability of the occurrence of disease Ex. Traveling to malaria endemic area 2. Stage of sub-clinical/pre-symptomatic The disease process is already begun inside the body but there is no recognizable sign and symptom . I t may be detected by laboratory investigation 18 3/28/2025 Teddy

19. Stages (cont’d) This stage include period of latency- b/n exposure to biological onset of disease biological onset of disease -initiation or induction of the disease process within the body. 3. Stage of clinical disease: recognizable s/s appear 4. stage of disability/death the disease left over damage to the body or ends with death 19 3/28/2025 Teddy

20. T he time course of infectious disease 1.Incubation period : time from exposure to development of disease. or the time interval between invasion by an infectious agent and the appearance of the first sign or symptom of the disease 2 . Period of illness : acute phase, most severe signs and symptoms & the immune system either overcomes pathogen or person dies . 3. 4.Communicable period :The period during which that particular communicable disease (infectious agent) is transmitted from the infected person to the susceptible host 20 3/28/2025 Teddy

21. Chain of disease transmission Is logical sequence of factors or links of a chain that are essential for the development of the infectious agent and propagation of disease. The six factors involved in the chain of disease transmission are : 1.Infectious agent (etiology or causative agent) 2. Reservoir 3. Portal of exit 4. Mode of transmission 5. Portal of entry 6. Susceptible host 21 3/28/2025 Teddy

22. Chain of Infection 22 3/28/2025 Teddy

23. 1. Infectious agent Is pathogen (disease causing micro organism ) that cause infection . The infectious agent is virus, bacteria, parasite or other microbes The agent causes infection and disease depending on its basic biological characteristics The outcomes of exposure to infectious agent can be depends on: Infectiousness Pathogenecity Virulence Immunogenicity 23 3/28/2025 Teddy

24. Infectiousness (infectivity) The ability of an infectious agent to cause infection in an exposed human host Infectivity is measured by Infection Rate (IR): 24 3/28/2025 Teddy

25. Pathogenicity The ability of an infectious agent to cause clinical disease among infected human hosts It is measured by clinical to sub-clinical ratio or proportion of clinical cases among infected human hosts Examples: High pathogenecity: HIV , Rabies, Measles… etc. Moderate pathogenecity: Mumps virus and Rhino virus Highly infectious but less pathogenic: Poliovirus 25 3/28/2025 Teddy

26. Virulence It is the ability of an infectious agent to cause severe clinical disease or death among clinical cases Virulence of the infectious agent can be measured by: Case fatality Rate (CFR) Hospitalization Rate (HR ) 26 3/28/2025 Teddy

27. Example Disease type Pathogenecity (Clinical: subclinical) Virulence (CFR) Poliomyelitis 1:99 2-10% Common cold 3:1 0% Rabies 100:0 100% AIDS 100:0 100% HIV and Rabies viruses are highly virulent with a fatality rate of 100% Rhino virus are less virulent with fatality rate close to 0% 27 3/28/2025 Teddy

28. Immunogenicity The infection’s ability to produce specific immunity It is defined as the ability of a pathogen or a vaccine to inducing an immune response after an infection or a vaccination respectively It may lead to protection against re-infection or re-activation with the same or similar pathogen in the future 28 3/28/2025 Teddy

29. Immunity… Immunity after infection may or may not be protective against re-infection or may last for variable periods of time some infectious diseases confer lifelong immunity others confer partial immunity against severe symptomatic infection, but much less against sub-clinical infection some confer no or negligible immunity 29 3/28/2025 Teddy

30. Immunity… Immunity can be acquired either after natural infection or indirectly Maternal antibodies protect the newborn child against many infections in the first few months of life Vaccine-induced immunity can be lifelong or temporary For temporary immunity, repeated booster vaccinations are necessary to ensure protection against the infection Example: TT vaccine 30 3/28/2025 Teddy

31. Immunity… Individuals gain protective antibodies in two ways: 1) They develop antibodies in response to infection, vaccine, or toxoid; immunity developed in these ways is called active immunity 2) They acquire their mothers’ antibodies before birth through the placenta or they receive injections of antitoxins or immune globulin; immunity that is acquired in these ways is called passive immunity 31 3/28/2025 Teddy

32. Exposure Disease outcome Disease Infection Infectiousness (Infection Rate) Pathogenecity (clinical : subclinical) Virulence (CFR, HR) Disease progression 32 3/28/2025 Teddy

33. Factors that influence disease development other than infectivity, pathogenicity, immunogenecity and virulence of the agent are: Strain of agent Dose of agent Route of infection Influence of human host age Influence of human host nutritional status Influence of human host immune response Influence of treatment Influence of seasonal variation, etc… 33 3/28/2025 Teddy

34. 2. Reservoir The starting point for the occurrence of a communicable disease is the existence of a reservoir or source of infection. Reservoir: Any person, animal, arthropod, plant or soil or substance (or combination of these) in which an infectious agent normally lives ,transforms, develops and /or multiplies. primarily for survival and where it reproduces itself in such a manner that it can be transmitted to a susceptible host. It is the natural habitat of the infectious agent 34 3/28/2025 Teddy

35. cont’d common reservoir Human being(STI, polio, measles…) vertebrate animals( rabies, anthrax invertebrate animals(tick, flea, louse environment( plants, soil, water- Ascariasis ) Reservoir Human reservoir Animal reservoir Non-living reservoir 35 3/28/2025 Teddy

36. cases Case: is defined as “a person in the population or study group identified as having the particular disease, health disorder, or condition under investigation” Carriers: the disease agent is not completely eliminated, It occurs either due to inadequate treatment or immune response. 36 3/28/2025 Teddy

37. Animal reservoirs Zoonosis : is an infection that is transmissible under natural conditions from vertebrate animals to man, e.g. rabies, plague, bovine tuberculosis….. There are over a 100 zoonotic diseases that can be conveyed from animal to man. Non-living things as Reservoir Soil and inanimate matter can also act as reservoir of infection. E.g. soil may harbor agents that causes tetanus, anthrax, and coccidiodomycosis. 37 3/28/2025 Teddy

38. 3. Portal of Exit The portal of exit is the route by which the infectious agent leaves the infectious hosts or reservoirs Many diseases have multiple reservoirs The most common portals of exit are respiratory tract, genitourinary tract, gastrointestinal tract, through skin, etc… 38 3/28/2025 Teddy

39. Portal of Exit… Portal of exit includes: Body secretions and discharges (mucus, saliva and tears, breast milk, urethral secretion, semen, vaginal secretion, pus, cervical secretion, exudates etc…) Excretions ( feces and urine), blood and tissues including placenta , etc… Flu or cold - mucous secretions Hepatitis A - stool 39 3/28/2025 Teddy

40. 4. Modes of Transmission Mode of transmission is the mechanism by which the infectious agent escapes from a reservoir and enters into a susceptible human host There are two major mechanisms of transmission Direct transmission Indirect Transmission 40 3/28/2025 Teddy

41. I. Direct transmission The immediate transfer of infectious agents from an infected host or reservoir to the appropriate portal of entry on the susceptible host. Transmission by direct contact Transmission by direct projection Trans-placental transmission Blood transfusion Organ transplantation 41 3/28/2025 Teddy

42. a) Transmission by direct contact Transmision by contact of skin, mucosa, or conjunctiva with infectious agents directly transferred from another person or vertebrate animal including: Touching: Trachoma (eye-hand-eye) Common cold (nose-hand-eye) Shigellosis (feces-hand-mouth) Viral hepatitis and HIV (through breaks in skin) S exual intercourse: HIV/AIDS kissing : mononucleosis Passing through birth canal: Gonorrhea 42 3/28/2025 Teddy

43. b) Transmission by direct projection Transmission by direct projection of saliva droplets created by expiratory activities such as breathing, coughing, sneezing, spitting, talking, singing etc… Example: common cold 43 3/28/2025 Teddy

44. c) Trans-placental transmission Trans-placental transmission of infectious agent is transmission from mother to fetus via the placental membrane Examples: HIV/AIDS Syphilis Toxoplasmosis Malaria etc... 44 3/28/2025 Teddy

45. d) Blood transfusion It is the transmission of disease through blood and blood products E. g. HIV and Hepatitis-B viruses e) Organ transplantation It may include kidney, liver and cardiac transplantation which transmit some communicable diseases from the donors to the receivers 45 3/28/2025 Teddy

46. II. Indirect transmission Airborne transmission Vehicle borne transmission Vector borne transmission Non vector intermediate host 46 3/28/2025 Teddy

47. a) Airborne transmission It is the transmission or dissemination of infectious agents by either suspended dust , particle or droplet nuclei, usually through respiratory tract. Microbial aerosols are suspensions of particles in the air consisting of partially or wholly of microorganisms Particles in the 1-5 micro meter range are easily drawn into the alveoli Examples: Tuberculosis : droplet nuclei during sneezing, speaking… Brucellosis : blood aerosols created during slaughter 47 3/28/2025 Teddy

48. b) Vehicle borne transmission It is the transmission of infectious agents by a vehicle Examples: Food, milk, water, soil, biological products, fomites (cooking utensils, towels, bed sheets, clothing, syringe, beddings, etc…) Vehicle: is any non-living substance by which an infectious agent can be transported and introduced into a susceptible human host through a suitable portal of entry 48 3/28/2025 Teddy

49. c) Vector borne transmission It is the transmission of infectious agents by a vector A vector is responsible for introducing the agent into the susceptible human host through a suitable portal of entry Biological vector: salivarian transmission (malaria by mosquito) Mechanical vector: trachoma by common fly Vector : is an organism usually an arthropod, such as insect, tick, mite, which transports an infectious agent to a susceptible human host or to a suitable vehicle 49 3/28/2025 Teddy

50. Vector borne transmission… Biologic transmission - when the agent undergoes physiologic changes within the vector, the vector is serving as both an intermediate host and a mode of transmission An agent undergoes part of its life cycle inside a vector before being transmitted to a new host Mechanical transmission - the agent does not multiply or undergo physiologic changes in the vector 50 3/28/2025 Teddy

51. d) A non-vector intermediate host These are hosts which are important for development of the infectious agent but don’t play an active role in transporting the agent to the susceptible human host Example : Aquatic snail for schistosomiasis 51 3/28/2025 Teddy

52. Mode of Transmission… A disease may often have several modes of transmissions It is vital to distinguish the predominant mode or modes of transmission so as to target preventive activities Example: malaria can be transmitted by blood transfusion, trans-placental or by vector, however, the vector borne transmission is the principal among all 52 3/28/2025 Teddy

53. 5. Portal of Entry Portal of entry is the route through which a microorganism enters into the susceptible human host Whether an agent will establish infection depends on the suitable portal of entry Example : No harm in ingesting the Clostridium tetani (it is in fact the normal flora of GIT system) 53 3/28/2025 Teddy

54. Portal of entry includes: Conjunctiva (trachoma, common cold) Nasal or upper respiratory tract (common cold, diphtheria) Lower respiratory tract (TB) Percutaneous (tetanus, hookworm) GIT (typhoid fever) Viganal (STDs/HIV/AIDS) Anal (STDs/HIV/AIDS) etc… 54 3/28/2025 Teddy

55. 6. Susceptible Human Host Host factors influence individual's exposure, susceptibility or response to infectious agent The susceptible human host is the final link in the infectious disease transmission process The susceptibility of the human host depends on: Genetic factors (including sex, blood group, ethnicity,…) Immunity due past infection or immunization Nutritional status etc Personal behaviors like drinking, smoking etc Anti- microbic ant- biotics availability and effectiveness 55 3/28/2025 Teddy

56. Prevention and control of CD Stopping the disease before it starts to occur OR Interrupting/slowing the progress of disease after exposure OR Prevents further disability or damage 56 3/28/2025 Teddy

57. Level of prevention Primary prevention Preventing disease before it starts to occur It includes: 1. Health promotion : general non-specific interventions that enhance health and the body’s ability to resist disease , such as measures aimed at the improvement of socio-economic status through the provision of adequately paid jobs, education and vocational training, affordable and adequate housing, clothing, and food, old-age pension benefits; emotional and social support, relief of stress, etc. 57 3/28/2025 Teddy

58. Level of prevention cont’d In short it is any intervention that promotes a healthier and happier life such as : - Breast feeding - balanced nutrient - physical exercise.. 58 3/28/2025 Teddy

59. Level of prevention cont’d 2. Prevention of exposure ex. Provision of safe water supply - environmental sanitation - proper excreta disposal - vector control.. - safe environment at home (e.g., proper storage of insecticides & medicines, out of children’s reach), at school and at work (e.g., proper ventilation, - monitoring of harmful substances in factories), and on the streets (e.g., driver licensing laws). 59 3/28/2025 Teddy

60. Level of prevention cont’d Secondary prevention After the biological onset of disease, but before permanent damage sets in. The objective here is to stop or slow the progression of disease so as to prevent or limit permanent damage, through the early detection and treatment of disease. e.g. breast cancer (prevention of the invasive stage of the disease), trachoma (prevention of blindness), & syphilis (prevention of tertiary or congenital syphilis) 60 3/28/2025 Teddy

61. Level of prevention cont’d Identify and treat asymptomatic persons who have already developed risk factors or preclinical disease but in whom the condition is not clinically apparent Early Dx and Rx Ex : screening 61 3/28/2025 Teddy

62. Level of prevention cont’d Tertiary prevention limitation of disability and rehabilitation . limit the physical, psychological, social and economical impact of disability Tertiary prevention activities involve: The care of established disease, with attempts made to restore to highest function, minimize the negative effects of disease, and prevent disease-related complications. Adjust individual to live with disability Ex: rehabilitation after stroke, polio, blindness…. 62 3/28/2025 Teddy

63. Principle of CD control 1. Measure directed against the reservoir If reservoir is human being - early Dx and Rx isolation : Keeping infected persons or animals in separate places or under certain conditions for as long as they can transmit disease. This prevents or limits the direct or indirect transmission of the infectious agent to those who are susceptible to infection. quarantine: limitation of the movement of apparently well person or animal who has been exposed to the infectious disease for a duration of the maximum incubation period of the disease. If reservoir is animal –eradication is possible 63 3/28/2025 Teddy

64. Principle of CD control cont’d 2.Interrupting the chain of transmission environmental sanitation personal hygiene/PPE vector control disinfection and sterilization 3. Reducing host susceptibility Immunization Prophylaxis health education personal protection 64 3/28/2025 Teddy

65. 65 Thank You STOP STIs 3/28/2025 Teddy