Prophylaxis of Infectious Diseases & Measures to Control Them

1. Prophylaxis of Infectious Diseases & Measures to Control Them

2. Prevention & control include: • Mass-scale measures aimed at improvement of public health, prevention of infectious diseases spreading; • Medical measures aimed at reduction of infectious morbidity & eradication of some diseases; • Health education & involvement of population in prevention or restriction of infectious diseases spreading; • Prevention of infectious diseases importing from other countries

3. Prophylaxis Preventive Ant- epidemic

4. The basic factors for an epidemic process development : • the source of infection; • transmission mechanism; • susceptibility of population

5. Control of infection source • Active detection of the sick persons (clinical examination, epidemical anamnesis, laboratory tests); • Isolation of patients (depends on clinical and medical prepositions – to a hospital or at home); • Treatment of patients (etiotropical, pathogenetic, symptomatic); • Discharging from a hospital after clinical recovering and negative laboratory tests.

6. Carriers should be revealed for medical examination and sanation. If animals are the source of infection (zoonoses) veterinary measures should be taken.

7. Disruption of infection transmission pathways • General sanitary measures (community hygiene) • Health education of population • Disinfection • Sterilization • Disinsection • Deratization

8. Disinfection Preventive Focal Current Final

9. Preventive disinfection Chemical Physical Mechanical Chlorine-, oxygen- containing substances, Phenols, Acids, Alkalis, hydrogen peroxide, formaldehyde Boiling, Steam, UV radiation & others Biological

10. Sterilization complete eradication of pathogenic and non-pathogenic microorganisms ( bacteria, viruses, fungi, spore forms) present on a surface, contained in a fluid, in medication, or in a environment. Can be achieved by applying the proper combinations of heat, chemicals, irradiation, high pressure, and filtration.

11. Sterilization is used for surgical, gynaecological, stomatological and other tools, dressing materials, linen, needles, syringes, etc. Nutrient media, laboratory ware, tools and instruments are sterilized in microbiology.

13. METHODS OF STERILIZATION There are four sterilization methods used in medical and dental offices: • 1. Steam (autoclave) sterilization • 2. Chemical vapor sterilization • 3. Dry heat sterilization • 4. Ethylene oxide gas sterilization

14. Each of these methods, when used properly, will achieve sterilization. Effective sterilization is dependent upon the ability of the sterilant (e.g., saturated steam, heat or gas) to have direct contact with all surfaces of the device or product being sterilized, for a specified time at a set temperature. Proper techniques in cleaning, preparation, packaging, and placement of supplies in the sterilizer chamber are critical for successful sterilant contact.

15. Steam sterilization Moist heat in the form of saturated steam under pressure is the sterilant used in the steam sterilizer (autoclave). Steam sterilization is the least time consuming, and the preferred, method of sterilization for heat and moisture stable medical devices. In steam sterilization it is important that the ambient air in the chamber and contents be completely removed at the beginning of the cycle so that the saturated steam can have direct contact with the items being sterilized. There are three main types of steam sterilization cycles: gravity, pre-vacuum, and flash.

17. Chemical vapor sterilization Unsaturated chemical vapor (a mixture of alcohol, water, ketones, and formaldehyde heated under pressure) is a typical sterilant used in this method of sterilization. Because of the low moisture content of unsaturated chemical vapor, it will not cause rust and corrosion on carbon steel instruments.

18. Dry heat sterilization Hot air is the sterilant used in the dry heat sterilizer (hot air oven). It is a slow process because it depends upon higher temperatures to incinerate microorganisms. This method of sterilization is used for heat-stable, moisture-sensitive, or steam impermeable medical devices and products. The Cox dry heat sterilizer is a rapid cycle dry heat sterilizer and is typically run for six minutes at 375°.

19. Ethylene oxide sterilization Ethylene oxide (EtO) is the sterilant used for gas sterilization. This method of sterilization is used for heat-sensitive items. EtO sterilization process is seldom used in office-based practice because of the long sterilization and aeration times required.

20. Disinsection Destroying Preventive Mechanical Physical Biological Chemical Genetic

21. Deratization (rodent control) Destroying Preventive Mechanical Biologycal Chemical

22. Quarantine measures • medical examination of persons who arrive into or depart from a given country, their vehicles & belongings; • availability of special medical documentation (international certificate of vaccination, certificate of deratization & the like) must be checked; • revealing & isolation of persons with infectious diseases, and isolation of persons who require medical observation; • disinfection, disinsection, deratization of means of transportation, of cargo & luggage (for specisl indications).

23. Measures to increase opportunity • Specific – preventive vaccinations, immune globulins, serums; • Non-specific – improving of living and labour conditions, nutrition, physical training.

24. E. Jenner(1749 - 1823)

25. L. Pasture(1822 - 1895)

26. D. Samoylovych(1724 - 1810)

28. INNATE IMMUNITY • The innate immune system, also known as non-specific immune system and first line of defense, comprises the cells and mechanisms that defend the host from infection by other organisms in a non-specific manner. This means that the cells of the innate system recognize and respond to pathogens in a generic way, but unlike the adaptive immune system, it does not confer long-lasting or protective immunity to the host. Innate immune systems provide immediate defense against infection, and are found in all classes of plant and animal life.

29. The major functions of the vertebrate innate immune system include: • Recruiting immune cells to sites of infection, through the production of chemical factors, including specialized chemical mediators, called cytokines; • Activation of the complement cascade to identify bacteria, activate cells and to promote clearance of dead cells or antibody complexes; • The identification and removal of foreign substances present in organs, tissues, the blood and lymph, by specialized white blood cells; • Activation of the adaptive immune system through a process known as antigen presentation; • Acting as a physical and chemical barrier to infectious agents; Cells of the innate immune response: mast cells, phagocytes, macrophages, neutrophils, dendritic cells, basophiles and eosinophiles, natural killer cells.

31. ADAPTIVE IMMUNITY The adaptive immune system is composed of highly specialized, systemic cells and processes that eliminate or prevent pathogenic growth. The adaptive immune response provides the vertebrate immune system with the ability to recognize and remember specific pathogens (to generate immunity), and to mount stronger attacks each time the pathogen is encountered. It is adaptive immunity because the body's immune system prepares itself for future challenges.

33. Immunization is the process by which an individual's immune system becomes fortified against an agent (known as the immunogen). When this system is exposed to molecules that are foreign to the body (non-self), it will orchestrate an immune response, but it can also develop the ability to quickly respond to a subsequent encounter (through immunological memory)

34. This is a function of the adaptive immune system. Therefore, by exposing an animal to an immunogen in a controlled way, its body can learn to protect itself: this is called active immunization. The most important elements of the immune system that are improved by immunization are the B cells (and the antibodies they produce) and T cells. Memory B cell and memory T cells are responsible for a swift response to a second encounter with a foreign molecule. Passive immunization is when these elements are introduced directly into the body, instead of when the body itself has to make these elements.

35. Types of immunoprophylaxis • Planned— vaccination is performed regardless of incidence of corresponding infectious disease. • Emergency — vaccination during epidemiological signs are performed: • During presentation of adverse epidemiological situations (especially severe infections, influenza), • When dealing with an unvaccinated (healthy) person who has had contact with a source of a pathogen, • When traveling of a person to an epidemiologically unfavorable territory, • Vaccination against tetanus and rabies.

36. Medical immunobiological preparations (MIBP) • Vaccines and antitoxins, which create an active immunity; • Immunoserums and immunoglobulins, that provide a passive defense; • Bacteriophages, which provide lysis of bacteria; • Cytokines (interferon and other biological immunostimulators).

37. ACTIVE IMMUNITY entails the introduction of a foreign molecule into the body, which causes the body itself to generate immunity against the target. This immunity comes from the T cells and the B cells with their antibodies. Active immunization can occur naturally when a person comes in contact with, for example, a microbe. If the person has not yet come into contact with the microbe and has no pre-made antibodies for defense (like in passive immunization), the person becomes immunized. 

38. The immune system will eventually create antibodies and other defenses against the microbe. The next time, the immune response against this microbe can be very efficient; this is the case in many of the childhood infections that a person only contracts once, but then is immune. Artificial active immunization is where the microbe, or parts of it, are injected into the person before they are able to take it in naturally. If whole microbes are used, they are pre-treated, attenuated vaccine.

39. Requirements for vaccines and antitoxins • Specificity; • Immunogenic; • Absence of negative side-effects; • Stable and prolonged preservation; • Easy to use; • High percentage of immunologic and epidemic effectiveness; • Low cost.

40. Type of Vaccines • Live; • Innactive; • Chemical; • Genetically-engineered; • Vector-recombinant; • Plants; • DNA-plasmids; • Mucosal vaccines.

41. Live Vaccines(tuberculosis, poliomyelitis, measles, epidemicparotitis, influenza, rabies, brucelliosis, epidemic typhus, Q fever, yellow fever, anthrax, tularemia, plague) • Avirulent strains of microorganisms, rid of pathogenic ability with preserved immunogenesis. • Benefits : — Complete and prolonged immune response after the introduction of the preparation — Single dose injections — have a long enough (more than a year) period of validity, freezing does not affect the effectiveness. • Short-comings : — requires strict maintenance of temperature during storage (4-8 °С), — possibility of reversion into another strain, which is associated with serious complications in the postvaccination period. • Do not contain preservatives, working with them it is important to maintain strict aseptic guidelines.

42. Dead (inactive) corpuscularvaccineshepatitis A, herpes, influenza, pertussis, tick-borne encephalitis, leptospirosis, poliomyelitis, cholera, typhoid fever, rabies Chemically or physically decontaminated microorganisms. • In addition to defensive (protective) antigens, the vaccines contain a considerable amount of bacterial cells (virions), which is associated with the reactivity of the preparation. • Vaccines are to be stored at 4-8 С. • Lower effectiveness when compared with live vaccines, repeated injections are required to build up a strong enough immunity.

43. Chemical Vaccines • Contain surface antigen determinants (considerably less additional substances); • Resistant to environmental factors; • very safe with the ability to use in different associated infections.; • Weak reactivity and immunogenesis, requires the vaccines to be infused multiple times.

44. Genetically-engineered vaccines • Are obtained with biotechnology by translocating genes, which code surface antigens of known pathogens, into attenuated strains of viruses, bacteria, yeast or eukaryot. • Recombinant vaccines are safe and effective, may be used to produce complex vaccines, which provide immunity against multiple infections.

45. DNA-Vaccines Plasmid DNA, which codes the surface antigens. • Immune response is similar to that of a live vaccine. • No chance of a reversion into a wild strain. • These are the vaccines of the future against HIV, rabies, influenza, hepatitis B & C, herpes, HPV, tuberculosis, malaria, ect.

46. Plant transgenetic vaccines • The principle based on using transgenic plants, which contain translocated genes of microorganisms. Consumption of these plants have shown to cause synthesis of specific antibodies in experimental animals. Benefits— • Oral ability to immunize; • More cost-effective than using vaccines.

47. Mucosal Vaccines Preparations, which provide synthesis of antibodies against proteins of adhesive bacterial cells (vibrions), as a result of which colonies of these pathogens cannot form on mucosal membranes(cholera, toxigenic strains of E. coli, HSV, pneumococcus). • After introduction intranasally and peros they provide a high titer of synthesis of IgA.

48. Anatoxins Decontaminated bacterial exotoxins with preserved antigenic and immunogenic properties. • Used for active prophylaxis of toxigenic infections; • Inherentlyhigh prophylactic effectiveness with a two-dose infusion, which reaches 95-100 %, also maintains a strong immune memory; • Relatively low reactivity; • Provides the development of antitoxic immunity (slightly less than the immunity after a disease); • Do not protect from carrier susceptibility • Widely used against diphtheria, tetanus, gangrene, botulism, cholera, staphylococcal andPseudomonas infection.

49. Complex Vaccines A combination (mixing) of vaccines, — using two-camber syringes with repeated injections in case of incompatible antigens. DTaP (diptheria tetanus and pertussis) vaccine, Influvac – influenza vaccine, meningococcal, pneumococcal, poliomyelitis

50. PHASES OF DEVELOPMENT OF POST-VACCINE IMMUNITY • Characteristic for the synthesis of antibodies and the development of cellular immunity. • First, latent phase – interval from the infusion of antigen to the appearance of antibodies, cytotoxic cells and mediators of latent hypersensitivity (persists for a couple day). • Second, growth phase– increase of antibodies and immunocompetent cells in the blood (from 4 days to 6 weeks). • Phase of regression of immunity –very fast at the beginning, then slows down, over a period of time from a couple years to decades.