Mapping mosquito diversity in Belgium and The Netherlands a tale - PowerPoint PPT Presentation

Mapping mosquito diversity in Belgium and The Netherlands – a tale of tyres and invasive mosquito species V. Versteirt Institute of Tropical Medicine

Introduction – Little is known in Belgium on mosquitoes • 1910-1930: first scattered records (Goetghebeur) • 1940’s-1950’s: Anopheles studies in polders • List of 1991: 24 species in Belgium • 2001: “Mosquitoes of Europe”: 26 species in Belgium • 2004: study of a number of specific companies (tyre import) – Recent decades: creation of suitable conditions for vector species • Changing eco-climatic conditions • Changing social habitats (closer contact vector-human) • Recurrent import of possible invasive species in to Europe • Increased transport (man & goods) – Yearly reports of arboviral outbreaks in Europe

Introduction: MODIRISK – Inventory of indigenous and exotic mosquito species in Belgium • Species distribution & diversity • Create distribution maps • Define mosquito rich areas – Increase knowledge on presence of vector species + main occurrence – Risk assessment

Introduction: MODIRISK – Sampling of >900 sites • Random selection (based on Corine dataset) – Urban – Agriculture – Nature • Manual selection Import risk areas – Harbours, airports – Zoo, nature reserves – Specific companies (activities) – 2007 & 2008: May-October – 2009 & 2010: validation sampling

Introduction: MODIRISK – Sampling in the Netherlands • April-October 2009-2010 • Longitudinal • Different habitats • IRA – Monitoring vector species – Data used for Modirisk models

Exotic does not mean invasive – Exotic/non-indigenous : accidentally or intentionally moved from its natural geographic range to a biotope where it was never before – Invasive: an exotic species that has a self-sustaining population, spreading in the receiving environment – Risks • Threat to biodiversit y – Outcompetition / replacement native fauna – Increase ubiquitous species • Threat to human and/or animal health – Biting nuisance – Transmission of arboviral diseases

Mosquitoes on the move? – Invasive Aedes mosquitoes • Container-breeding species • Eggs: resistant to desiccation • No restrictive host preferences • Dissemination by human activities Photo F. Schaffner • Adapted to temperate climate (+ winter diapause) – (1) Introduction – (2) Establishment – (3) Spread • Intercepted exotic species • Introduced exotic species • Invasive species…

Mosquitoes on the move – Europe: • Aedes aegypti ( Stegomyia aegypti ) * • Aedes albopictus ( Stegomyia albopicta )* • Aedes atropalpus ( Georgecraigius atropalpus)* • Aedes japonicus ( Hulecoeteomyia japonica ) ‡ • Aedes koreicus ( Huleocoetomyia koreica ) ‡ ‡ = Belgium * = The Netherlands

Aedes aegypti • Important disease vector: YF, DENV, CHIKV • Act as vector in overseas territories and was vector in Europe • Present in the past in Southern Europe • Invades large parts of tropical region • Spreading at the Black See cost (since 2004), introduced • in Madeira (2004) • Introduced by second hand tyre trade in NL (2010)

Aedes aegypti

Aedes albopictus • Late 1800’s USA (Hawaii, ship) • 1985 Continental USA (tyres from Japan) • 1979 (1975): Albany • 1990: Italy • 1999 (1998): France • 2000: Belgium • 2001: Montenegro • 2003: Switzerland - Greece • 2004: Spain - Croatia • 2005: The Netherlands – Slovenia – Bosnia and Herzegovina • 2011: Turkey

Aedes albopictus • Vector for several arboviruses: Chikungunya, Dengue, Yellow fever, la Crosse virus, Equine Encephalitis and West Nile • Biting nuisance, very aggressive! (day-biter) • Strong competitor (outcompetes native mosquitoes) – Spreading gradually in Europe (Southern, moving norhtwards) – Active (flying up to 1.5km) – Passive larvae (international tyre and lucky bamboo trade ) – Passive adults (cars and/or other vehicules)…

Scientific relevance Example of Aedes albopictus actively spreading in Southern France Source: EID

Aedes albopictus in Europe

Aedes atropalpus • Native: North and Central America • Climate assessments – suggest spread in Europe • Readily bites humans; nuisance species • Positive for WNV in US; vector status not clear • Italy (1996), France (2004), Netherlands (2009) • Introduced by used tyre trade

Aedes japonicus – Intercepted in New Zealand (1993, 1998 & 1999) • (Laird et al . 1994; Fonseca et al . 2001): water tank, machinery & used tyres (offloaded from ships with origin Japan) – First established outside its native range in the USA in 1998, spread to 22 states incl. Hawaii, and parts of Canada • (Williges et al., 2008) – Europe: • France (Normandie), 2000: detected on a platform for imported used tyres (then eliminated) (Schaffner et al., 2003) • Belgium, since 2002: established, but so far only on one/two storages of used tyres (Versteirt et al., 2009) • Central Europe: Rapid spread in northern Switzerland and southern Germany (Schaffner et al., 2009; Becker et al., 2011; Schneider 2011)

Aedes japonicus in Europe • … Non spreading in Belgium Rapidly spreading in Switzerland and Germany

Aedes japonicus – Biting nuisance – Putative vector of pathogens of medical and/or veterinary – significance: possible WNV vector, avian malaria, JEV, but status unclear – Potential threat to biodiversity (outcompeting native mosquitoes, USA)

Aedes koreicus – Introduced and established in Belgium (2008) • Morphological particularities indicate Cheju-Do Island as the geographical origin of the introduced population (Versteirt et al., submitted) – Found in several sites in Italy (Belluno Province) 2011 • Link between Belgium & Italy???? – Native from Asia • Original larval habitat: rock and tree holes • Winter diapause at egg stage – Potential vector of arboviruses (Japanese encephalitis) – Vector for filariosis (dogs)

Other mosquitoes intercepted – Aedes triseriatus – Orthopodomyia signifera – Toxorhynchites rutilus • All found in imported tyres ! (France) • All eradicated at entery point!…

Global village

Global traffic From Tatem & Hay (2007). Climatic similarity and biological exchange in the worldwide airline transportation network. Proc. R. Soc. B 274, 1489–1496 Comparison of airports based on annual average traffic-scaled climatic similarity index and traffic ranking

Global traffic From Tatem et al. 2006. Global traffic and disease vector dispersal. Pnas The 10 sea traffic routes identified with the strongest risk factors for importation and establishment of each of four principal members of the An. gambiae complex

Import pathways – Main = second hand tyre trade! • Japan (Asia) – USA – Europe • Asia – Europe – Often via USA! • Ports connected (large containers) – ship & plane – Other trade • e.g. Lucky Bamboo (the Netherlands) – Areas with similar climate at certain moments= highest risk! – World becomes smaller = more connections • Less barriers for mosquitoes to ‘travel’

Relevance – First countrywide study in Europe – Unique sampling scheme – Importance monitoring vectors – Import = related to specific activities – Risk of introduction remains substantial

Policy relevance • Need for surveillance & rapid detection methods – Import areas like ports/airports, but especially second hand trade • Need for clear and uniform eradication protocol – Who – What & how • Follow up & continuation?