3. Changes in these factors caused by the
social and natural environment reflect
on the intensity of the epidemic process.
4. Thus the efficacious prophylactics and effective
fight against infectious diseases are possible
only when the antiepidemic measures are
directed in three ways:
measures eliminating or decontaminating
the source of infection;
measures stopping the mechanism of
transmission of infection;
measures stimulating insusceptibility of the
population to a certain disease.
5. I. MEASURES ELIMINATING OR
DECONTAMINATING THE SOURCE OF
INFECTION
It is the main trend in the fight against infectious diseases.
* measures for extermination - elimination of the sick
animals (carriers of infection). The method is the best one
in case of infected wild animals as well as domestic
animals;
* measures for derattization - used at rodents, reservoirs of
infections;
* sanitary measures - concerning domestic and farm
animals (for example, carriers of brusellosis). In this way
animals are used for the purposes of the farms
simultaneously with the measures for their recovery.
6. Measures for extermination are not applicable at
anthroponosus infectious diseases where the source
of infection is the man - a sick person or a carrier of
infection. In this case the aim is to decontaminate the
source of infection putting it in such conditions in
which the possibilities for transmission of infection
are cut off.
*isolation of the sick persons - in an infectious
ward or at home. Complete influencing of the source
of infection is impeded also by the characteristics of
the clinical course of the disease - inapparent, mild
clinical forms, chronic forms, etc.
7. Localization and decontamination of the source of
infection depend on:
* living conditions - conditions facilitating
transmission of infection to other persons should be
eliminated;
* attitudes of the population - whether people
seek doctors' help immediately, refusal of hospitali-
zation, etc. as well as degree of health knowledge
and responsibility for the economic costs.
* possibilities for specific, etiologic treatment of
the sick persons and carriers of infection.
8. Urgent prevention is also one of the measures
for influencing the source of infection. Urgent
prevention - it is the use of prophylactic and
curative means to prevent development of the
disease from the carriers of infection in incubation.
For this purpose immune serums, vaccines,
bioproducts, chemotherapeutic agents –
sulfonamides, antibiotics, etc. are applied.
9. II. MEASURES STOPPING THE
MECHANISM OF TRANS-MISSION OF
INFECTION
These measures are various ones. They are
mainly related to the specific characteristics of
the mechanism of transmission of the different
infectious diseases. Generally, it is very
difficult to carry out such measures.
10. 1. Diseases belonging to the group of enteric
infections.
The measures require the agents of infection
in the faeces of the sick persons not to get
through food, water, etc. into the
gastrointestinal tract of the healthy people.
11. Sanitary measures eliminating the faecal-oral
way of infection are of crucial importance:
development and urbanization of the built-up
areas;
water supply, sewerage;
decontamination of the sewerage waters;
collection and decontamination of the hard
wastes;
sanitary measures in public catering;
following the regulations of sanitation;
school hygiene;
health knowledge of the population.
12. 2. Diseases belonging to the group of
respiratory infections:
Gauze masks, aeration and ventilation,
bactericidical lamps, disinfection.
13. 3. Diseases belonging to the group of blood
infections:
Character, access and effectiveness of the
measures applied depend on the biological
carrier:
agromeliorative measures;
hydrotechnical measures;
disinsection and derattization;
means of individual prevention;
stimulating accumulation of health
knowledge.
14. 4. Diseases belonging to the group of covering
infections:
They are transmitted through the personal
belongings, household goods, etc.
* disinfection;
* hygienic measures for decontamination;
* stimulating the accumulation of health
knowledge of the population.
15. III. MEASURES STIMULATING
INSUSCEPTIBILITY OF THE
POPULATION
A perspective for prevention and fight
against infectious diseases is
development of specific
insusceptibility of the population to
infectious diseases.
16. IMMUNITY represents a complex of
preventive physiologic responses of the
whole organism, i.e. it is a way of
prevention of the organism from protein
bodies carrying themselves foreign gene
information.
17. Immune system recognizes the relevant
antigens through its immunocompetent
cells and reacts against them producing
IMMUNE RESPONSE as well as
developing immune memory and immune
tolerability.
18. IMMUNE RESPONSE is a complex
reaction of the organism induced by the
antigen penetrated in it, which
morphologic base is proliferation and
differentiation of the immunocompetent
cells.
19. Recognition of the antigen is made with the help
of two types of lymphocytes:
* T-lymphocytes - they have developed their
immunologic competence through thymus and
that is why they are called "thymus-dependent";
* B-lymphocytes - they have developed their
immunologic competence through the 'Fabricius
bursa" (for the birds) or through its equivalent
for the mammals, probably bone marrow or part
of the lymph tissue of the intestines - 'Payer's
plaques', appendix and tonsils.
20. In the course of the evolution the following
types of immunity have been developed:
1. Hereditary (species) immunity:
It is formed during the philogenetic
development of the individual. It represents a
state of insusceptibility of the organism
related to the species to which the man or the
animal belong. It is inherited (for example,
people do not suffer from hen cholera,
animals - from measles).
21. 2. Acquired (individual) immunity.
It is formed during the ontogenetic development of the
individual. The ability of the organism to develop
ontogenetic mechanisms is a result from its philogenesis.
Individual immunity is divided as follows:
A. Naturally acquired immunity, which, on its part, is
divided to:
* passive - due to antibodies, inherited from the mother;
* active – postinfectious, domestic immunity.
B. Non-naturally acquired (pos-timmunization)
immunity, divided to:
*active - developed after application of vaccines and
toxoids;
*passive - after administration of readymade antibodies
through serums and immunoglobulins.
22. The difference between these two types
of development of immunity is related to
the way of development as well as the
level of its intensity and duration.
23. According to the mechanism of development of the
immune response immunity is divided as follows:
• humoral immunity - it acts thro-ugh B-lymphocytes as
well as antibo-dies circulating freely as immunoglobulins
in the blood and the other body liquids. The antibodies
react directly to the antigens forming a type of response
"antigen-antibody" - precipitation, neutralization,
accumulation,etc. depending on its conditions.
• cell immunity - it acts through the circulating T-
lymphocytes together with the non-immunoglobulin
mediators of the lymph function (activated macrophages).
Local immunity is an antigen (mainly IgA) and is cell
mediated - in the immunosecretory system of the mucous
of the gastrointestinal tract and respiratory ways (the
entrance of infection).
24. Collective immunity - it is the ability of the
human collective to resist to the activity of the
agents of the infectious diseases and to
prevalence of the endemic process. It is
determined by the specific immune structure
of the population as well as the possibility for
realization of the mechanism of transmission
of infection in the real circumstances.
25. Immune structure is a concept reflecting the
distribution of the members of the group
depending on the degree of their susceptibility
to infectious diseases.
26. Non-specific immunologic structure - it
characterizes the degree of insusceptibility of
the population to all infectious diseases. It is
measured by different immunologic,
physiologic, and other methods.
27. Specific immunologic structure - it
characterizes insusceptibility of the
population to a certain infectious disease. It
is measured by the percentage of the
individuals possessing immunity.
28. Collective immunity is not a simple sum of the
individual immunity of the separate members
of the group. Different individuals may belong
to the group as follows:
with highly intensive immunity;
with partial immunity;
with out developed immunity.
29. There are many different contingents of susceptible
individuals:
newborns and toddlers (due to undeveloped immune
system);
recovered individuals with short-term and slightly
intensive immunity;
individuals immigrating to regions, which are
endemic for certain diseases;
old-aged individuals (with reduced resistance of the
organism);
individuals suffering from innate and acquired
impairments of the immune system,
ofimmunogenesis, etc.
30. Characteristics of the three directions of
prevention and fight against infectious diseases
provide the possibility for achieving the necessary
practical results at many infectious diseases if the
measures influencing the preventive directions are
simultaneously carried out – decontamination of the
source of infection, stopping the mechanism of
transmission of infection and stimulating the
specific insusceptibility of the population. This is
the basic principle of the antiepidemic fight.
31. One of these three ways of activity is the
basic one as the other two are
complementary depending on the nature
of the infectious disease and the situation.
32. ANTIEPIDEMIC MEASURES IN THE EPIDEMIC CENTRE
I. Measures to the patient
1. Early finding and recognition of the disease.
2. Putting proper diagnosis.
clinical methods;
laboratory methods;
epidemiological methods.
3. Registration and informing for the infectious disease.
quick informing - form N 58;
Registration book of infectious diseases - form N 60;
Registration book of hospital infections - form N 11.
33. 4. Isolation of the patient in an infectious ward or at home:
transportation of the patient - in a suitable way for him/
her; safe for the other persons;
sanitary manipulation - bathing, decontamination of the
clothes and underwear, eliminating parasites;
specific etiologic therapy;
dehospitalization of the patient:
* after full clinical recovery
* elimination of the pathogenic agent (the infect)
* sanitary manipulation;
* disinfection of the clothes, underwear, etc.
Chronically sick patients are under dispensary observation.
34. II. Measures to the other persons (contacting
ones as well as carriers of infection)
1. Measures to contacting persons:
epidemiological investigation for finding of all
contacting persons;
registration - "Book for persons in contacts with
acutely infected patients" - form N 61;
medical observation - a maximal incubation
period, thermometring, clinical examination;
35. sanitary manipulation - when necessary;
quarantine of the contacting persons -
highly infected ones in isolation - serologic,
microbiological, virusologic analyses;
active or passive immunization;
urgent prevention with antibiotics and
chemotherapeutical agents.
36. 2. Measures to the carriers of infection:
finding - epidemiological investigation;
- microbiological investigation;
sanation of the carriers of infection - directed to
elimination and cleaning of the pathogenic micro-
organisms;
isolation.
37. SPECIFIC PREVENTION
Definition: An approach for development of
non-natural specific insusceptibility to the
etiologic agent of a certain infectious disease.
38. Vaccination process: An interaction between the
vaccine agent and the human organism with its
individual characteristics. It is a complex
reaction, which includes as follows:
specific immune reorganization resulting in
development of immunity (the aim of the
immunization);
concomitant processes of non-specific
reorganization (directed to restoration of the
homeostasis) as well as allergization, clinically
manifested or asymptomatic.
39. Different preparations are used for
development of immunity - vaccines, toxoids,
serums, immunoglobulins.
40. Live vaccines: Immune preparations, containing
bacteria and viruses that have lost their
pathogenic properties but preserved their
immunologic properties. Such types of vaccines
are as follows: against tuberculosis,
polyomielitis, measles, mumps, influenza,
smallpox, tularemia, brucellosis, anthrax, plaque,
yellow fever, etc. These vaccines develop
intensive and longterm immunity.
41. Inactivated vaccines: They are prepared from
the cultures of different infects, inactivated
physically (heating up) or chemically (formalin,
phenol, alcohol, etc.) - abdominal typhus,
paratyphus, cholera, who-oping-cough,
leptospyroses, etc. as their immunogenic
properties are preserved.
Recombinant vaccines: They are made with the
help of gene engineering with hybridoma
technic, etc.
42. Chemical vaccines: They are full antigen vaccines,
derived chemically from bacterial cultures.
They are maximally lacking ballast substances, side
protein components and cause relatively low
allergization of the organism. They are stable.
(Against enteric infections – abdominal typhus,
paratyphus A and B, together with a tetanicus toxoid).
Toxoids: They are derived from the products of the
microorganisms, mainly their toxins, through their
inactivation (by formalin or heating up) - against
diphtheria, tetanus, staphylococcus infection, etc.
43. Protective antigens: Immunization substances
related to the pathogenic factors of bacterial
and virus cells. Such antigens are discovered
lately in plaque and whooping-cough bacteria,
streptococcus, staphylococcus, anthrax bacilli,
Ricketsias, etc.
44. Serums: Immune preparations proving passive
immunologic prevention for a short time (2 to 4
weeks). They are ready-made antibodies (anthrax,
whooping-cough, epidemic meningitis, tetanus,
diphtheria, botulism, staphylococcus infection).
Bacteriophages: live agents, which are parasites
in the bacterial cell - abdominal typhus,
shigelloses, salmonelloses, cholera. They have
limited application.
45. Interferon: a protein synthesized from the cells in
response to a virus infection making the other cells
resistant to infection. It inhibits virus proliferation
through non-immunologic mechanisms (virus
interference) - application at influenza,
parainfluenza, coxsackie B3, ECHO-13,
adenoviruses, enteric infections, etc.
Immunoglobulins: simple, hyperimmune.
46. Application of vaccines:
* subcutaneous, intracutaneous, oncutaneous,
peroral, intranasal, aerosol method.
Application of serums and inimunoglobulins:
* subcutaneous, intracutaneous (strictly
according to the method of Bezredka).
47. Postimmunization reactions of the organism:
general - changes in the body temperature and
state of the organism;
local - hyperemia and edema.
Postimmunization complications:
serum disease, anaphylactic shock, postvaccination
encephalitis, etc.
48. Contraindications:
severe states of the organism: acute infectious
diseases, active form of tuberculosis,
decompensated valvular disease, hypertension,
renal diseases (nephritis), diabetes, broncl
asthma, anemia, cachexia, the second half of
pregnancy, etc.
specific for the disease.
49. The effect of immunizations depends on:
compatibility of the immunizations;
the scheme and dosage of the vaccines;
reactivity of the organism;
size of the immune layer.
50. Organization of application of immunizations:
bioproducts supply;
quality of the bioproducts;
storage conditions and transportation of the
bioproducts.
52. Possibilities for application of the vaccines:
according to the aims of prevention;
according to epidemiological indications.
Immune prevention with serums: when
necessary.
53. DISINFECTION
1. Generally, disinfection (decontamination) is a
complex of methods and means directed to
elimination of the source of infection in the
environment. The concept includes the
following stages: disinfection itself together
with sterilization and antiseptic method,
disinsection and derattization.
55. Types of disinfection according to its goals
and tasks are as follows:
Prophylactic (preventive) disinfection:
It is carried out where a centre of infection
does not exist but there are facilitating
conditions of its development. It is performed
systemically under plans for certain periods of
time - in nursery schools, schools, hospitals,
cinemas, theatres, railway stations, catering
establishments, of drinking water, milk, food,
etc.
56. Disinfection of the centre of infection. It is
carried out in the centre of infection. Its aim is the
elimination of the pathogenic mechanisms in the
environment of the patient producing the
microorganisms and contaminating the
environment. Disinfection performed during the
course of
the disease is called current disinfection. After
recovery of the patient, its hospitalization or
after a lethal outcome the final (ending)
disinfection is performed. The quality of the
current disinfection determines the complex of
tasks, methods and means for the final
disinfection.
57. STERILIZATION. A method for elimination of
all microorganisms (pathogenic and saprophyte,
viruses, bacteria, mould) in their different forms -
vegetative and spores
58. SANITATION. A method for the rapid
reduction of the microbial flora in an object in
the environment (for example, after washing). It
is widely applied in everyday life as a preventive
measure.
59. ANTISEPTIC METHOD. A method for
prevention of development of microorganisms
on the human skin and mucous.
60. DISINSECTION: elimination of the
arthropods, carriers of infectious diseases.
DERATTIZATION: elimination of the
rodents, natural reservoirs of infections.
61. Methods of disinfection:
Biologic method: biological filters for
decontamination of the water (on the base of the
microbial antagonism).
Mechanical method: cleaning, wash ect.
Physical method: sun shining, ultra-violet rays,
ionizing radiation, supersound, dry heat for
sterilization by dry air, wet heat – sterilization
and vapour under pressure.
Chemical method: use of chemical compounds-
disinfectants.
62. Methods of disinsection:
Biological method: use of the natural enemies of
the harm arthropods - predatory animals
(the fish gambusia), parasites, pathogenic
microorganisms (Bacillus thuringiensis),
genetically changed, sexually sterile populations.
Mechanical method: cleaning, wash, etc.
Physical method: high temperature - hot dry and
wet air for vapouring, sterilization, burning
out, etc.
63. 5. Chemical method: insecticides:
larvacides - for elimination of larvae;
acaricides - for elimination of Acars;
ovocides - for elimination of their eggs;
pesticides - for elimination of weeds;
* attractants - attracting insects;
* repellents - repelling insects.
64. Insecticides for arthropods depending on their
way of penetration in the organism are as
follows:
fumigants - gas insecticides - they act through the
respiratory system;
intestinal insecticides - through the digestive
tract;
contact insecticides - act at contact to outer parts
of the insects:
a) with residual effect;
b) without residual effect.
65. Methods of derattization:
1.Preventive (prophylactic) derattization:
a) sanitary and technical means – lack of access of
the rodents to the buildings – openings of drainage,
doorstills, etc.
b) sanitary and hygienic measures – lack of access to
food.
Exterminatory derattization:
a) biologic method – natural killers of the rodents.
b) mechanical method – use of traps;
c) chemical method – use of chemical compounds –
rodenticides.
