1
Epidemiology
of infectious diseases
Kolářová M., EPI Autumn 2019
2
THE CAUSATIVE AGENT OF INFECTION (bacteria, viruses, fungi, prions, protozoa)
1. the presence of rezervoir (source) of infection
man, animal at the ende of incubation period
acute stage
cariers
2. the way of transmission A/ direct contact
touching, kissing or sexual intercourse (Staphylococcus spp., Gonococcus spp.,HIV …),
- vertical transmission – from mother to fetus (VHB, VHC, HIV, listeria, rubella, cytomegalovirus…)
B/ indirect contact
- inhalation of droplets containing the infectious agents (TBC, measles, influenza…)
- ingestion of food or water that is contaminated (salmonella, giardia, Norwalk virus, VHA….)
- biological transmission by insects (malaria, borellia….)
3. the susceptibility of the population or its individual members to the organism
concerned Host factors : a g e , n u t r i t i o n, g e n e t i c s
i m m u n i t y – natural (nonspecific),
- acquired
THE INFECTION
= 1. source of infection
……….
0
10000
20000
30000
40000
50000
60000
1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018
0
10000
20000
30000
40000
50000
60000
1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018
Varicella
5
Varicella (chickenpox)
6
Varicella (chickenpox). Lesions at various stages, including vesicles, can
be seen.
0
10000
20000
30000
40000
50000
60000
1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018
Varicella
Kampylobakteriosis
Salmonelosis
0
10000
20000
30000
40000
50000
60000
1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018
Varicella
Kampylobakterióza
Salmonelóza
231,7/100 000
111,3/100 000
490,4/100 000
0
2000
4000
6000
8000
10000
12000
14000
16000
18000
20000
1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018
Virové a střevní infekce
Zahájeno očkování proti
rotavirovým infekcím
Očkování proti RG je v ČR od roku 2007 zařazeno mezi
doporučená očkování :
Rotarix od 6 týdnů věku nejlépe dokončit do 16. týdne věku (max.
24. týdne),
Rotateq 1. d. od 6 týdne věku do 12. týdne, dokončit nejlépe do
10
Rotavirus
0
200
400
600
800
1000
1200
1400
1600
1800
1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018
VHA 15,8/100 000
VHC 10,4/100 000
VHB 0,8/100 000
VHE 3,9/100
Virus Hepatitis B
By GrahamColm at
English Wikipedia, CC
BY-SA 3.0,
0
200
400
600
800
1000
1200
1400
2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012
Název grafu
Gonokokové infekce
11,1/100 000
Syfilis
9,7/100
000
Second
ary
syphilis
with
Gonococcal
Helical structure of Treponema
14
Helical structure of Treponema pallidum with the periplasmic
flagella.
15
Secondary syphilis with typical skin rash.
16
Gonococcal urethritis.
0
500
1000
1500
2000
2500
19891990199119921993199419951996199719981999200020012002200320042005200620072008200920102011201220132014201520162017
Tuberkulóza
2 079 případů = 20,2/100
000
505 případů = 4,9/100
000
Ziehl-Neelsen stain of 'cords' of Mycobacterium
18
Ziehl-Neelsen stain of 'cords' of Mycobacterium tuberculosis
isolated from a broth culture. Tubercle bacilli aggregate end to
end and side to side to form serpentine cords, especially in
broth cultures.
19
Slime-producing coagulase-negative staphylococci. Scanning electron micrograph of the
surface of an intravascular catheter incubated in vitro with (a) slime-producing and (b)
nonslime-producing strains of Staphylococcus epidermidis. With permission from
Christensen.9
20
Staphylococcus aureus
21
Staphylococcal nasal carriage. This patient had a small staphylococcal abscess beneath the
mucosa of the nose, illustrating how Staphylococcus aureus, which colonizes the nares, can
infect skin and submucosa. Intact mucosa is highly resistant to infection; such infections
usually occur as a result of defects in the mucosal membranes or via hair follicles inside the
nose.
22
Septic pulmonary emboli. Multiple nodular pulmonary infiltrates secondary
to a dialysis catheter-associated infection. The patient presented with high
fevers, cough and pleuritic chest pain. Staphylococcus aureus was isolated
from multiple blood specimens.
23
◼ Impetigo in a child.
24
◼ b-Hemolytic streptococci group A on a blood agar plate.
Note the clear b-hemolytic zone.
25
◼ Electron microscopy of group A streptococcus. The
fuzzy M protein layer can be seen protruding from
the cell wall..
26
Erysipelas. Note the sharp demarcation of the
affected skin.
27
Scarlatina (scarlet fever)
28
◼ Necrotizing fasciitis caused by group A strepococci.
There is only moderate erythema but at surgery there
was extensive soft tissue damage.
29
Mixed culture of two morphotypes of Enterobacteriaceae
on blood agar plate (Escherichia coli and Salmonella spp.).
30
Pseudomonas aeruginosa monotrichous polar flagellum
seen on electron microscopy.
31
Burned leg that has been superinfected with Pseudomonas
aeruginosa.
32
Cultured Helicobacter pylori in coccoid and bacilli forms,
bound to immunomagnetic beads.
33
Obtained after an outbreak, this micrograph depicts Gram-positive
Clostridium difficile bacteria.
Source: CDC
34
Under a moderately-high magnification of 8000X, this colorized scanning
electron micrograph (SEM) revealed the presence of a small grouping of Gramnegative
Salmonella typhimurium bacteria that had been isolated from a pure
culture. See PHIL 10986 for a black and white version of this image.
35
36
Primoinfection HIV
37
Colonies of Nocardia asteroides showing smooth chalkywhite
appearance.
38
Primary cutaneous nocardial infection is characteristically painless, localized
and slowly progressive. (a) There is marked swelling and erythema in this
child's finger. (b) However, because the finger was painless the child was not
brought to medical attention until the infection had progressed to involve the
entire finger.
39
Typical rash of meningococcal septicemia. Fine
erythematous macules and petechiae are present in some
areas.
40
Morbilli (Measles). A disseminated erythematous rash can be
seen over the trunk and arms.
41
Rubella. A pink macular rash can be seen on the forearm.
42
Rubella
43
Parotitis epidemica ( mumps)
44
Sarcoptes scabiei
45
46
Scabies
47
Crusted or Norwegian scabies in a patient who has AIDS.
48
Giemsa stain of blood with Borellia burgdorferi.
49
Tick - Ixodes ricinus
50
Lyme boreliosis (LB)
51
LB - Typical erythema migrans rash.
52
A blood-engorged female Aedes albopictus mosquito feeding
on a human host.
53
Francisella tularensis
54
Tularemia
55
Tularemia
56
Hlístice Trichinella spiralis
57
Pathogenesis of rabies.
58
1. the presence of source of infection
is the site or sites in which a disease agent normally lives and reproduces in
diferrent stages of a disease
May be classified as:
- human - at the ende incubation period,
if is ill,
reconvalescent,
carriers – healthy,
chronic diseases
- animals - at the ende incubation period,
if is ill,
carriers – healthy,
reconvalescent, chronic
59
2. the metod of transmission
A/ direct contact
touching, kissing or sexual intercourse (Staphylococcus spp.,
Gonococcus spp.,HIV …),
- vertical transmission – from mother to fetus (VHB, VHC, HIV,
listeria, rubella, cytomegalovirus…)
B/ indirect contact
- inhalation of droplets containing the infectious agents (TBC,
measles, influenza…)
- ingestion of food or water that is contaminated (salmonella,
giardia, Norwalk virus, VHA….)
- biological transmission by insects (malaria, borellia….)
60
3. the susceptibility of the population or its individual
member to the organism concerned, and the characteristic
of the organism itself.
Host factors :
Non specific immunity
Barrier action (natural barrier)
External barrier:
skin , mucosa
Secretion of skin and mucosa
Accessory organ
Internal barrier: placenta, blood-brain barrier
Phagocytosis
Humoral action :
Complement, Lysozyme, Fibronection, Cytokines.
Specific immunity
Humoral immunity
Immunoglobulin: IgG, IgM, IgE, IgA, IgD
Cell mediated immunity
61
THE CAUSATIVE AGENT OF INFECTION (bacteria, viruses, fungi, prions, protozoa)
1. the presence of rezervoir (source) of infection
man, animal at the ende of incubation period
acute stage
cariers
2. the way of transmission A/ direct contact
touching, kissing or sexual intercourse (Staphylococcus spp., Gonococcus spp.,HIV …),
- vertical transmission – from mother to fetus (VHB, VHC, HIV, listeria, rubella, cytomegalovirus…)
B/ indirect contact
- inhalation of droplets containing the infectious agents (TBC, measles, influenza…)
- ingestion of food or water that is contaminated (salmonella, giardia, Norwalk virus, VHA….)
- biological transmission by insects (malaria, borellia….)
3. the susceptibility of the population or its individual members to the organism
concerned Host factors : a g e , n u t r i t i o n, g e n e t i c s
i m m u n i t y – natural (nonspecific),
- acquired
THE INFECTION
= 1. source of infection
……….
62
63
Organisms vary in their capacity to survive in the free state
and to withstand adverse environmental conditions, for
example:
* heat, cold, dryness.
Sporo-forming organisms, such as tetanus bacilli
which can survive for years in a dormant state,
have a major advantage over an organisms like
the gonococcus which survive for only a very short time
outside the human host.
64
Colonisation and contamination of humans
by micro-organisms.
Many parts of the body are colonized by normal flora, which
can be the source of endogenous infection. Large
numbers of micro-organisms are found in moist areas of
the skin (e.g. the groin, between the toes), the upper
respiratory tract, the digestive tract (e.g. the mouth, the
nasopharynx), the ileum and large intestine, the anterior
parts of the urethra and the vagina.
Other routes are interhuman transmission of infections and
exposure to exogenous contamination.
65
Routes of transmission
➢ Air
➢ Food, Drink or Water
➢ Direct or indirect contact
* Transplacental
➢ Insects (Artropods)
66
Main portals of entry
➢ Respiratory tract
➢ Gastro-intestinal tract
➢ Genito-urinary tract
➢ Direct break through skin
* surgical and wounds
➢ Direct into blood via needles/catheters
The pathogenicity of pathogen is related to:
➢ invasiveness
➢ virulent
➢ number of pathogen (infectious dosis)
➢ mutation (variability)
67
68
Prevention of infectious diseases
Isolation of patients:
- Dpt. of infectious diseases,
- „high degree of isolation“ (ebola)
- at home,
- barriers nursing technique
SOURCE
OF INFECTION
MODE
OF TRANSMISSION
SUSCEPTIBLE
ORGANISM
69
Prevention of infectious diseases
SOURCE
OF INFECTION
MODE
OF TRANSMISSION
SUSCEPTIBLE
ORGANISM
HANDWASHING, DISINFECTION OF HANDS
LINEN WASHING,
CLEANING
GOOD PREPARING OF FOOD, SAFE
WATER……..,
………
DISINFECTION
STERILIZATION
70
Prevention of infectious diseases
SOURCE
OF INFECTION
MODE
OF TRANSMISSION
SUSCEPTIBLE
ORGANISM
i m m u n i t y
– natural (nonspecific),
- acquired (vaccination)
71
◼ The distribution of the
smallpox rash is
usually similar to that
shown here. It is
most dense on the
face, arms and hands,
legs and feet. The
trunk has fewer pocks
than the extremities.
72
Smallpox is a disfiguring disease. Three out of ten cases may die. It is caused by variola
virus. The disease is spread by secretions from the patient's mouth and nose, and by material
from pocks or scabs. It is transmitted directly from one person to the next. Close contact with
patients, or their clothing or bedding, is thus required for infection. A patient who has
developed the distinctive symptoms of smallpox will have been exposed to the virus about two
weeks previously.
73
If the epidemiology is know, we can interfere with
transmission:
„BREAKING THE CHAIN OF INFECTION“
Different infections have different epidemiologies
and thus require different methods of control
74
In the practical part it is preoccupied with
preventive measures
repressive measures
related to infectious diseases