tick-borne encephalitis - who tick-borne encephalitis (tbe) -human tbe cases transmitted by tick...

Download Tick-borne encephalitis - WHO Tick-borne encephalitis (TBE) -human TBE cases transmitted by tick bites,

Post on 01-Aug-2020

1 views

Category:

Documents

0 download

Embed Size (px)

TRANSCRIPT

  • Tick-borne encephalitis: Disease epidemiology and burden

    of disease

    Jochen Süss National Reference Laboratory for Tick-borne Diseases

    Friedrich-Loeffler-Institute, Jena, Germany

    WHO-Meeting of the Strategic Advisory Group of

    Experts on Immunization (SAGE) 5-7 April 2011

    CCV/CICG, Geneva

  • Tick-borne encephalitis (TBE)

    - human TBE cases transmitted by tick bites, and – more rarely – by milk and milk products

    - important viral zoonose

    - the most important cause of viral infections of the central nervous system in Central and Eastern European countries and in Russia

    - the most important and widespread of arbovirus diseases that can be transmitted by ticks in Europe (and Asia?)

  • TBEV - Host - Vector - Interactions

    Pathogen

    Vector

    (i) (ii)

    (iii) e.g. rodents, birds (humans)

    e.g. Ixodes ricinus TBEV prevalence 1-3% Germany, Austria 1.7% Lithuania 14.3% special focus Switzerland 3-5% (25%) Latvia

    I. persulcatus acc. to P. Nuttal, 1999, mod.

    Vertebrate host

    focal nature of the disease!

  • Ixodes ricinus and I. persulcatus in Europe and Far East

    according to Lindgren, Jaenson, Sonenshine, Minar

  • Phylogenetic tree of flaviviruses (glycoprotein E)

    Source: Heinz and Stiasny, 2010; Jääskeläinen et al., 2010; Chausov et al., 2010 (mod.)

    Sofjin

    Siberian/Siberian

    Siberian/Baltic

    Neudoerfl

    Zausaev Vasilchenko

    Ixodes ricinus

    Ixodes persulcatus

  • TBEV subtype pattern in Europe and Asia

    EU SI FE

    EU

    SI

    FE SI EU

    EU

    FE FE SI

  • Alimentary transmission of TBEV (dairy products from livestock)

    Raw milk: goat < sheep < dairy cow

    Russia Czech Republic Hungary Austria Slovakia Lithuania Latvia Poland Lithuania Estonia Albania Bosnia Serbia

    Recent alimentary outbreaks: 2007: Hungary/Lakhegy: 154 exposed individuals 25 confirmed cases (Balogh et al., 2009) 2008: Austria/Vorarlberg: 7 exposed individuals 4 confirmed cases (Holzmann et al., 2009)

    XXXXX: from the 1990 more milk-borne cases and outbreaks!

    Historical alimentary outbreak: 1954: Slovakia/Roznava: > 261 patients (Blaškovič, 1954)

  • TBE is a notifiable disease in 16 European countries (Austria, Czech Republic, Estonia, Finland, Germany, Greece, Hungary, Latvia, Lithuania, Norway, Poland, Russia, Slovak Republic, Slovenia, Sweden, Switzerland) . At present, TBE is not notifiable in Belgium, France, Italy, Portugal, Spain, Denmark, and the Netherlands. In 19 European countries TBE is endemic AND which report reliable data:

    Between 1990 and 2009 169,937 TBE cases were reported, an average of 8,497 cases/year.

    This is considered an underestimate due to insufficient routine diagnostics and surveillance!

    In Belgium, Portugal, Spain, and the Netherlands no authochthonous TBE cases were reported; the reasons are largely unknown. (Süss, J., Eurosurveillance 2008; 13(26))

  • TBE: Reporting structures / surveillance activities Clinically and diagnostically confirmed AUTOCHTHONOUS TBE cases Detection (and characterization) of TBEV in unengorged ticks (selected points) Detection of TBEV in rodents (and specific antibodies) Surveillance in wildlife Surveillance in livestock sentinels (antibodies; goat and sheep flocks)

  • TBE risk areas have been monitored by TBE incidence since 2007 (Robert-Koch-Institute, 2007). Risk areas (districts) are defined as areas with a mean of 1 case per 100.000 inhabitants in the district (Landkreis) in the course of 5 years. Previously, TBE risk areas in Germany were determined by the number of confirmed human cases per district a year and not by incidence

    Def. risk area (Germany) – Robert-Koch-Institute

  • TBE – case definition (Germany and other countries)

    Clinical picture typical of TBE

    Detection of TBEV-specific IgM and IgG antibodies in the serum

    Place of exposure

    Typically a biphasis course with flu-like symptoms during the first phase, signs of meningitis, encephalitis or radiculitis or mixed forms after an asymptomatic period without fever

    Detection of TBEV-specific antibodies in the CSF – increased CSF serum index cross reactive antibodies against other flaviviruses (or vaccinations) – ELISA test versus neutralization test moderate pleocytosis

    Further epidemiological circumstances: history, vaccination status, tick bite, exposure in known risk areas, raw milk in risk areas

    However, case definitions vary in different countries

  • TBE – case definition (Germany and other countries)

    Clinical picture typical of TBE

    Detection of TBEV-specific IgM and IgG antibodies in the serum

    Place of exposure

    Typically a biphasis course with flu-like symptoms during the first phase, signs of meningitis, encephalitis or radiculitis or mixed forms after an asymptomatic period without fever

    Detection of TBEV-specific antibodies in the CSF – increased CSF serum index cross reactive antibodies against other flaviviruses (or vaccinations) – ELISA test versus neutralization test moderate pleocytosis

    Further epidemiological circumstances: history, vaccination status, tick bite, exposure in known risk areas, raw milk in risk areas

    However, case definitions vary in different countries

  • Rhineland Palatinate

    Baden- Wuerttemberg

    Bavaria

    Hesse Thuringia

    1998 Definition risk area risk area

    Development of TBE risk areas in Germany

    1998

    1998: 63 TBE risk districts 2010: 136 TBE risk districts

    2010 (Germany:440 districts)

  • Recorded (!) TBE cases in Europe and Russia 1990 – 2009 (2010)

    Europe without Russia

    Russia

    Europe including Russia

    (Süss, 2011, TTBDIS)

    2010 preliminary

  • 0

    1000

    2000

    3000

    4000

    5000

    6000

    7000

    TBE in Europe 2000 – 2009

    CZ 6542

    LT 3848

    D 2977 SLO 2620

    LV 2608

    PL 2362 EST 1740

    S 1549 CH 1328

    H A SK FIN

    HR I

    TBE cases

    N F DK 25

    without Russia

    Number of TBE cases in 10 years

    Czech Republic Lithuania Germany Slovenia Latvia Poland Estonia Sweden Switzerland Hungary Austria Slovakia Finland Croatia Italy Norway France Denmark

    (Süss, unpublished)

  • 0

    2

    4

    6

    8

    10

    12

    14

    RU

    TBE in Europe 2000 – 2009 (incidence)

    CZ

    LT

    D

    SLO

    LV

    PL

    EST

    S CH H A SK FIN

    HR

    I

    TBE incidence

    N

    Mean value of incidence in the last 10 years

    RU

    Estonia 12.91 Slovenia 12.82 Latvia 11.31 Lithuania 11.15 Czech Rep. 6.19 Russia 3.02 Sweden 1.77 Switzerland 1.76 Slovakia 1.36 Austria 0.88 Hungary 0.72 Poland 0.62 Finland 0.42 Germany 0.36

    (Süss, unpublished)

  • China: North east, Heilongjiang province, (Zhi Lu et al., Vector-borne and Zoonotic Diseases, 2008). Kazakhstan: East region and region Almaty (Pavel N. Deryabin, pers. commun., 2010)

    Mongolia: North, (Walder et al., IJMM 296 S1, 69-75 (2006) (Khasnatinov et al., 2010: first fatal case, Far East subtype)

    Japan: Hokkaido (Ikuo Takashima et al.)

    Korea: (Su-Yeon Kim et al., Vector-borne and zoonotic diseases (2008), no cases

    TBEV outside Europe

    Kyrgyzstan: siberian subtype (Atkinson, 2010)

  • Korenberg, E., Advances in Virus Research 74 (2009) 124-144

    TBE-incidence (per 100.000 inhabitants)

    TBE cases (incidence) in Russia 1950 - 2009

    Climate change? Anthropogenic influence? Vaccination coverage? Reporting? Diagnostics?

    ?

    ?

    1990 - 2009

    ?

  • Age & Clinical Manifestation of TBE

    acc. to Kaiser, 2005 (unpublished)

    66 62 54 41 33

    14

    34 38 46 59 67

    86

    1-15 16-30 31-45 46-60 61-75 76-90 Age (Years)

    0%

    20%

    40%

    60%

    80%

    100%

    Meningitis Encephalitis/Myelitis

  • Long-term prognosis in TBE (encephalomyelitis)

    Patients 57

    n

    De

Recommended

View more >