Download Mode of transmission

GEOGRAPHIC DISTRIBUTION
OF DISEASES
Jana Dáňová
Department of Epidemiology
GEOGRAPHIC DISTRIBUTION
OF DISEASES
Diseases exist in environment
independent on human
↓
Etiologic agent
Animal reservoir
Vector
Biotop
GEOGRAPHIC DISTRIBUTION
OF DISEASES
NATURAL FOCI

limited foci
silent

diffuse foci
active
human is the coincidential part
of the transmission
VECTOR - BORNE DISEASE
reservoir and source of the disease are
animals and also vectors
person to person transmission does
not exist
mode of transmission is vector – borne
VECTOR – BORNE DISEASE
types of vector
Mosquito
Fly
Tick
Flea
Louse
ARBOVIRAL DISEASES
more than 100 types of viruses (Arboviruses) could
cause different infections of a man
diseases are caused by different etiologic agents
clinical symptoms of diseases are very similar
according clinical symptoms are known
4 main syndroms:
Acute benign fevers
Meningitis, encephalitis
Hemorhagic fevers
Polyarthritis with fever and exantema
ARTHROPOD-BORNE VIRAL DISEASES
ARTHROPOD-BORNE VIRAL ENCEPHALITIDES
Mosquito-borne - Eastern equine enc., Western equine enc.,
Japanese enc., St.Louis enc., West Nile enc., Murray Valley enc.
Tick-borne - Central european tick-borne enc.,
Spring-summer enc., Louping ill
ARTHROPOD-BORNE VIRAL FEVERS
Mosquito-borne Venezuelan equine enc., Chikungunya, O´nyongnyong
Tick-borne - Colorado tick fever
ARTHROPOD-BORNE VIRAL HEMORRHAGIC FEVERS
Mosquito borne - dengue, yellow fever
Tick-borne - omsk hemorrhagic fever
CENTRAL EUROPEAN TICK-BORNE
ENCEPHALITIS
Clinical symptoms: diphasic meningoencephalitis
first symptoms are not typical – influenza like
second part after several days of recovery –
meningeal symptoms
Etiologic agent: virus of central european TBE (Flavivirus)
Reservoir: rodents, ticks
Mode of transmission: bite of infective tick, consumption
of milk from certain infected animals
Incubation period: 7 – 21 days, commonly 14 days
TICK-BORNE ENCEPHALITIS
source NIPH
Středoevropská encefalitida přenášená klíšťaty
8
7
6
nemocnost
5
4
3
2
1
0
1965
1970
1975
1980
1985
1990
1995
2000
Tick - borne encephalitis - Czech Republic 1990 - 2010
abs.numbers
1029
816
744
629
709
623
619
647
643
606
633
589
551
546
507
490
415
356
422
338
182
1990
1991 1992 1993 1994
1995 1996 1997 1998
1999 2000 2001 2002
2003 2004 2005 2006
2007 2008 2009 2010
Tick-borne encephalitis and lyme disease Czech Republic 1993 - 2010
abs.numbers
tick borne
6300
lyme dis.
4357
4192
4062
3847
3773
3547
3658
3677
4350
3863
3647
3558
3588
3243
2722
2470
2138
1027
629
1993
619
1994
743
1995
571
1996
719
415
422
490
1997
1998
1999
2000
633
2001
647
2002
606
2003
507
2004
643
2005
2006
546
633
816
2007
2008
2009
589
2010
DENGUE FEVER
Clinical symptoms: an acute febrile viral disease,
headache, myalgia, arthralgia, retroorbital pain
dengue hemorrhagic fever – bleeding manifestations and
involvement of organs, maculopapular rash
Etiologic agent: dengue virus types 1, 2, 3, 4
Reservoir: man, also mosquito
Mode of transmission: by the bite of infective mosquitoes
Aedes aegypti
Incubation period: 3 – 14 days commonly 4 – 7 days
Dengue - Czech Republic 1999 - 2010
abs.numbers
17
15
11
10
9
7
7
6
4
3
2
1
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
YELLOW FEVER
Clinical symptoms: an acute viral disease, sudden onset,
fever, chills, headache, muscle pain, nausea, vomiting,
the pulse slows (Faget´s sign), hemorrhagic symptoms –
epistaxis, buccal bleading, hematemesis (vomito negro),
melena, jaundice is present in the second part of disease
Etiologic agent: virus of yellow fever (flavivirus)
Reservoir: in urban areas – man and Aedes aegypti
in forest areas mainly monkeys, forest mosquitoes
Mode of transmission: bite of infective mosquitoes
Incubation period: 3 – 6 days
AEDES
MALARIA
Clinical symptoms: varied clinical symptoms – fever, chills,
headache, icterus, renal, liver failure
Etiologic agent: Plasmodium – Pl. vivax, Pl. ovale,
Pl. malariae, Pl. falciparum.
Reservoir: humans – human malaria only important reservoir
Mode of transmission:
bite of infective female
anopheles mosquito
Incubation period: 12 days Pl. falciparum, 14 d. Pl.vivax, ovale
30 days Pl.malariae
MALARIA
Malárie, 1950-2003, případy hlášené hygienické službě
40
35
počet případů
30
25
20
15
10
5
0
1950
1955
1960
1965
1970
1975
1980
1985
1990
1995
2000
ANOPHELES MOSQUITO
Imported Malaria to Czech Republic 1998 - 2010
abs.numbers
29
26
25
23
23
22
21
18
16
16
14
13
11
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
EHRLICHIOSIS
Clinical symptoms: myalgia, arthralgia, headache,
lymphadenopathy
1. Sennetsu fever (Japan)
2. American ehrlichiosis
Etiologic agent: Ehrlichia sennetsu
Ehrlichia chaffeensis
Ehrlichia phagocytophila
(Rickettsiaceae  Ehrlichiaceae  Ehrlichia)
Mode of transmission: tick borne disease
by Sennetsu fever vector unknown
Incubation period:
1. Sennetsu fever (Japan) - 14 days
2. American ehrlichiosis - 7 – 21 days
Ehrlichiosis cases (caused by Ehrlichia chaffeensis)
reported to CDC by state health departments
1999-2006
Age-specific incidence of Ehrlichiosis (caused by
Ehrlichia chaffeensis), reported to CDC 2001-2002
BABESIOSIS
Clinical symptoms: fever, chils , myalgia, fatigue,
jaundice, hemolytic anemia
Etiologic agent: Babesia microti, Babesia equi,
Babesia divergens

Protozoal parasits
Reservoir: rodents for Babesia microti
cattle for Babesia divergents
Mode of transmission: tick
B.microti - Ixodes scapularis
B. equi – Ixodes pacificus
B.divergens – I.ricinus
Incubation period: 1 week – 12 month
TULAREMIA
Clinical symptoms: clinical manifestation depents
on route of transmission
ulceroglandular type
oropharyngeal type
oculoglandular type
pleuropulmonary type
Etiologic agent: Francisella tularensis
Reservoir: wild animals – especially rabbits,
also ticks
Mode of transmission: contact with infected animals, handling or
ingesting insufficiently cooked meat, vectorborne transmission
Incubation period: 1 – 14 days, usually 3 – 5 days
19
66
19
68
19
70
19
72
19
74
19
76
19
78
19
80
19
82
19
84
19
86
19
88
19
90
19
92
19
94
19
96
19
98
20
00
20
02
20
04
19
64
nemocnost
TULAREMIA
Tularémie
12
10
8
6
4
2
0
Tularemia - Czech Republic 1998 - 2010
abs.numbers
222
225
113
110
103
94
83
87
65
60
51
1998
1999
2000
2001
2002
2003
2004
53
54
2005
2006
2007
2008
2009
2010
PLAGUE
Clinical symptoms: first symptoms are nonspecific - fever,
headache, mylagia
specific symptoms – lymphadenitis, inquinal area
(90%), less common axilar, cervical area,
pneumonia
untreated bubonic plague – case fatality 50 – 60 %
Etiologic agents: Yersinia pestis
Reservoir: wild rodents
Mode of transmission: bubonic plague – flea - Xenopsylla cheopis
Pneumonia – person to person
transmission
Incubation period: bubonic plague 1 – 7 days
pneumonia – 2 – 4 days
XENOPSYLLA CHEOPIS
LYME DISEASE
Clinical symptoms: skin lesion – „erythema migrans“
systemic symptoms, neurologic, rheumatologic
and cardiac involvement
Etiologic agent: Borrelia burgdorferi sensu lato
B.garinii, B.afceli (Europe)
Borrelia burgdorferi sensu stricto
(North America)
Reservoir: wild rodents
Mode of transmission: tick-borne transmission
Incubation period: for erythema migrants 3 – 32 days after tick
exposure
20
04
20
03
20
02
20
01
20
00
19
99
19
98
19
97
19
96
19
95
19
94
19
93
19
92
19
91
19
90
19
89
19
88
19
87
19
86
nemocnost
LYME DISEASE
Lymeská choroba
70
60
50
40
30
20
10
0
Lyme disease - Czech Republic 1993 - 2010
abs.numbers
6300
4062
4350
4357
4192
3847
3773
3863
3547
3658
3677
3559
3243
3588
3243
2722
2470
2138
1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010
RABIES = LYSSA
an acute fatal viral encephalomyelitis - case fatality rate
100%, death is due to respiratory paralysis
Infectious agent: Rhabdovirus genus Lyssavirus
Occurence: worldwide, estimated 40 000 deaths a year,
almost in developing countries
Reservoir: foxes, dogs, coyotes, wolves, bats
Mode of transmission: by a bite or scratch of animal
(organ transplantation)
Incubation period: usually 2-8 weeks
5 days – 1 year or more
HANTAVIRAL DISEASES
Hantaviruses infect rodents worldwide, several
species have been known for some time to infect
humans with varying severity – increased
vascular permeability, hypotensive shock,
hemorrhagic manifestations
HEMORRHAGIC FEVER WITH RENAL
SYNDROME
HEMORRHAGIC FEVER WITH PULMONARY
SYNDROM
HANTAVIRAL HAEMORRHAGIC
FEVER WITH PULMONARY
SYNDROM
an acute zoonotic viral disease- fever, myalgia,
GI complaints respiratory distress, hypotension
Infectious agent: multiple Hantaviruses
(Sin Nombre, Bayou)
Occurence: first described summer 1993
North and South America
Reservoir: deer mouse and other rodents
Mode of transmission: aerosol transmission from rodents
excreta, indoor exposure in poorly ventilated homes
Incubation period: 2 weeks ( few days – 6 weeks)
HANTAVIRAL HEMORRHAGIC
FEVER WITH RENAL SYNDROME
an acute zoonotic viral disese characterized by fever, back
pain, hemorrhagic manifestations and renal involvement
Infectious agent: Hantanviruses, Hantaan virus(Asia),
Dobrava (former Yugosl.) Puumala (Europe)
Occurence: worldwide, more comon among rural
population, spring, early summer
Reservoir: field rodents
Mode of transmission: aerosol transmission from rodents,
humans are accidental host
Incubation period: few days – 2 months, aver. 2 – 4
weeks
THANK YOU FOR ATTENTION