Transcript Antеpidemic measures

Prophylaxis of
Infectious Diseases &
Measures to Control
Them
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
Prophylaxis
Preventive
Antepidemic
The basic factors for an epidemic
process development :
 the source of infection;
 transmission mechanism;
 susceptibility of population
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.
Carriers should be revealed for medical
examination and sanation.
If animals are the source of infection
(zoonoses) veterinary measures should be
taken.
Disruption of infection transmission
pathways
 General sanitary measures (community
hygiene)
 Health education of population
 Disinfection
 Sterilization
 Disinsection
 Deratization
Disinfection
Focal
Current
Preventive
Final
Preventive disinfection
Mechanical
Biological
Chemical
Chlorine-,
oxygencontaining
substances,
Phenols,
Acids,
Alkalis,
hydrogen
peroxide,
formaldehyde
Physical
Boiling,
Steam, UV
radiation &
others
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.
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.
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
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.
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.
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.
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°.
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.
Disinsection
Destroying
Preventive
Mechanical
Physical
Biological
Chemical
Genetic
Deratization
(rodent control)
Destroying
Preventive
Mechanical
Biologycal
Chemical
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).
Measures to increase
opportunity
 Specific – preventive vaccinations,
immune globulins, serums;
 Non-specific – improving of living and
labour conditions, nutrition, physical
training.
E. Jenner
(1749 - 1823)
L. Pasture
(1822 - 1895)
D. Samoylovych
(1724 - 1810)
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.
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.
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.
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)
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.
Types of immunoprophylaxis
 Planned — vaccination is performed regardless of incidence
of corresponding infectious disease.
 Emergency — vaccination during epidemiological signs are
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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.
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).
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 premade antibodies for defense (like in passive
immunization), the person becomes
immunized.
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.
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.
Type of Vaccines
 Live;
 Innactive;
 Chemical;
 Genetically-engineered;
 Vector-recombinant;
 Plants;
 DNA-plasmids;
 Mucosal vaccines.
Live Vaccines
( tuberculosis, poliomyelitis, measles, epidemic parotitis,
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.
Dead (inactive) corpuscular vaccines
hepatitis 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.
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.
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.
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.
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.
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.
Anatoxins
Decontaminated bacterial exotoxins with preserved antigenic
and immunogenic properties.
 Used for active prophylaxis of toxigenic infections;
 Inherently high 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 and Pseudomonas
infection.
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
PHASES OF DEVELOPMENT OF POSTVACCINE 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.
Methods of introduction of
vaccines
 Intramuscular — vaccines are injected into the deltoid
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muscle for adults, and for children younger than 18
months– into the quadricept femoris muscle.
Subcutaneous— into the subscapular region or in the
upper third of the arm.
Intracutaneous – into the upper external surface of the
arm (BCG) or in the internal middle surface of the
forearm(tuberculin, other allergens).
Scarification – in the internal surface of the forearm
(used during vaccinating with live viruses against –
plaque, contrax, Q fever, brucellosis, tularemia.
Peroral – introduced as a liquid (poliomyelitis) or tablet
(smallpox, cholera, the plague) form.
Methods of introduction of
vaccines
Intracutaneous
Intramuscular
Methods of introduction of
vaccines
Subcutaneously
Perorally
Immunization against polio (OPV)
BCG (Bacille Calmette-Guérin)
vaccine
PASSIVE IMMUNITY
Passive immunization is where pre-synthesized elements
of the immune system are transferred to a person so that
the body does not need to produce these elements itself.
Currently, antibodies can be used for passive
immunization. This method of immunization begins to
work very quickly, but it is short lasting, because the
antibodies are naturally broken down, and if there are no
B cells to produce more antibodies, they will disappear.
Passive immunization occurs physiologically,
when antibodies are transferred from mother
to fetus during pregnancy, to protect the fetus before and
shortly after birth.
Artificial passive immunization is normally
administered by injection and is used if there
has been a recent outbreak of a particular
disease or as an emergency treatment for
toxicity (for example, for tetanus). The
antibodies can be produced in animals
("serum therapy") although there is a high
chance of anaphylactic shock because of
immunity against animal serum itself.
Thus, humanized antibodies produced in
vitro by cell culture are used instead if
available.
Preparations for creating a passive
immunity
Homogenous immunoglobulin
 —
preparations
containing
specific
immunoglobulin (up to 95 % IgG) for specific
pathogens (tetanus, influenza, botulism, tickborne encephalitis) or against multiple pathogens
of infectious diseases (human immunoglobulin).
Obtained from the serum or plasma of healthy
people.
 introduced intramuscularly or intravenously, the
half-life is approximately 4 weeks.
Heterogenous serum
– preparations for prophylaxis and treatment of viral
(rabies,
tick-borne
encephalitis),
bacterial
(leptospirosis, anthrax), toxic (diphteria, botulism)
infections.
 Are obtained from the blood of animals vaccinated
multiple times,
 Introduced intramuscularly using the method of
Bezredka, taking into account the risk for severe
complications (anaphylactic shock, serum disease)
 Have a shorter half-life in the organism.
Contraindications to prophylactic
vaccination
 Acute fever
 Recently sustained infections
 Chronic diseases
 Second half of pregnancy, first nursing
period
 Allergic diseases and states
 Oncology pathology
Postvaccination reactions
 These are the clinical and laboratory signs of
unstable pathological (functional) changes in
the organism, which appear in relation to
vaccination.
 Reactions may be local and general, in this
account severe.
 A severe local reaction at the injection site is
edema of soft tissues greater than 50mm
in diameter, infiltrate greater than 20mm in
diameter, hyperemia greater than 80mm in
diameter.
 Severe general reaction are characterized by
an increase of body temperature to ≥ 39оС.
Postvaccination reactions
 Increase of body temperature < 39º С;
 Increase of body temperature ≥ 39° С (severe
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general);
Pain, edema of soft tissues ≥ 50 мм, hyperemia at
the injection site ≥80 mm, infiltrate ≥20 mm (severe
local);
Lymphoadenopathy;
Headache;
Irritability, sleep disturbance;
Rash of non-allergic etiology;
Anorexia, stomach pain, dyspepsia, diarrhea;
Catarrhal phenomena;
Myalgia, artralgia;
Transitory thrombocytopenia.
Postvaccination complications
– are stable functional and morphological changes in
the body, beyond the physiological norms and lead to
significant violations in health (frequency– 1:100 000
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vaccinations):
Post-injection abcess;
Anaphylactic shock or reaction;
Allergic reaction (Quinke edema, syndrome of StevenJohnson, Layel);
Febrile syndrome;
Afebrile seizure;
Cold subcutaneous abcess;
Trophic ulcer greater than 10 mm;
Regional lymphadenitis;
Keloid scar;
Generalized BCG-infection, osteomyelitis, osteitis.
 Anaphylactic shock– characterized by a sudden
drop of arterial pressure and disturbance of cardiac
fuction. Appears, as a rule, in the first 30 minutes
after vaccination, requires resuscitation.
 Seizures without increased body temperature
(afebrile seizures) – appears during DTaP
vaccinations (1 out of 30-40 thousand vaccines). In
contrast to febrile seizures, appear the irritation of
definite areas of the brain and meninges with
vaccine antigens.
 Encephalitic reaction (serous meningitis) – has
a frequency of 1:10000 vaccinations against
measles and parotitis. Develops as a result of
irritation of the meninges by vaccine viruses.
Characterized
by
headaches,
neurological
symptoms, and sudden disappearance without any
long-term effects.
Postvaccination complications
Keloid scar after vaccination
Postvaccination complications
Vaccination eczema
Multiform exudative erythema in a 1 year-old
child after vaccination against small-pox
Erythema
Innoculation of virus on the left
eyelid
Postvaccination complications
(serum disease)
PROPHYLAXIS FOR POSTVACCINE
COMPLICATIONS
 Strictly following the guidelines of vaccinating;
 Careful selection of people for vaccinations
including contraindications;
 Following the instructions of transporting and
storing vaccines;
 Observing proper dosage of drugs and
intervals between vaccination.
Ant-epidemic measures in the focus
 Examination by epidemiologist or a rural
physician;
 Final disinfection;
 Taking of material for microbiologic
investigation;
 Observation during the incubation period;
 Health education of population.
Thanks For Your Attention!