European Mosquitoes and Their Implication for West Nile Virus Biology

European mosquitoes and their implication for West Nile virus biology

ESCMIDJordi Figuerola eLibrary © by author ESCMID eLibrary Taylor et al. 2001. Phil.Trans.R.Soc. © by author WEST NILE VIRUS (WNV)

Emerging zoonotic arbovirus (arthropod-borne virus) Flavivirus genus. Culex mosquitoes are the most important vectors.

ESCMID eLibrary © by author Russia, 1999- 2002 Czech Rep. 1997 y 1999

France 2000 Italy, 1998 France, 1962-65 Romania, 1996-98 Portugal, 1971

Israel, Israel, 1951, 1998-2000 1957 Morocco, Tunisia, 1997 1996 Algeria, 1994 ESCMID eLibraryEgypt, 1950 © by author Russia, Russia, 1999- 2005-11 2002 Czech Rep. 1997 France, 2003, 2004, y 1999 2006 Austria, 2008-2010 Hungary 2004-2011 France 2000 Italy, 1998 France, 1962-65 Romania, 1996-98 Portugal, 1971 Romania, 2010-11 Italy, 2008-2011 Bulgaria, 2010

Spain, 2007, 2010-11 Greece, 2010-11 Portu- gal, Tunisia, 2003 Israel, Israel, 1951, 2004, 1998-2000 1957 2010 Israel, 2000-2011 Morocco, Tunisia, Morocco 1996 1997 2003, 2010 Algeria, 1994 ESCMID eLibraryEgipto, 1950 © by author 2018: 1503 human in the EU.

ESCMID eLibrary © by author ESCMID eLibrary © by author ESCMID eLibrary © by author ESCMID eLibrary © by author ESCMID eLibrary © by author IDENTIFICATION OF HOST SPECIES

ESCMID eLibrary Alcaide et al. 2009. Plos One © by author ESCMID eLibrary © by author 10% 16% 15%

10% 11% 10% 11% 21% 13% 15% 27% 11% 46%

54% 33% 18%

ESCMID eLibrary © by author ESCMID eLibrary © by author ESCMID eLibrary © by author ESCMID eLibrary © by author What is the vectorial competence?

• Vectorial competence is the capacity of a mosquito to transmit the virus.

ESCMID eLibrary © by author • In Europe we have more than 100 species of mosquitoes.

• The vectorial competence widely differs between species.

• But data for European species is very scarce. ESCMID eLibrary © by author What is the vectorial competence?

Mosquito species Infection rate (%) Transmission rate (%) Aedes albopictus 40 26,7 Ochlerotatus caspius - 0 Ochlerotatus detritus - 21

Culex modestus - 40-55

Culex pipiens 33-90 20-60 Culex pipiens pipiens 26-63 0-33 Culex pipiens modestus 20,7 8,7 CulexESCMIDpipiens hybrids 41 eLibrary7 Reviewed in Vogels et al. 2017. Emerging Microbes & Infections © by author Estimating WNV transmission risk

• Risk (birds) = A * Fa * Fa * Cv

• A = Abundance of mosquitoes • Fa = Fraction of blood meals comming from birds • Cv = Vector competence estimated as the proportion of bites from infected mosquitoes that transmit de virus ESCMID eLibrary © by author Figure 4. WNV transmission risks for each different mosquito species estimated from the 12 sampling sites for birds, horses and humans.

Muñoz J, Ruiz S, Soriguer R, Alcaide M, et al. (2012) Feeding Patterns of Potential West Nile Virus Vectors in South-West Spain. PLoS ONE 7(6): e39549.ESCMID doi:10.1371/journal.pone.0039549 eLibrary http://www.plosone.org/article/info:doi/10.1371/journal.pone.0039549 © by author Figure 4. WNV transmission risks for each different mosquito species estimated from the 12 sampling sites for birds, horses and humans.

ESCMID eLibrary © by authorRoiz et al. 2015. Plos One Culex perexiguus Culex pipiens Culex modestus

ESCMID eLibrary © byCulex theileri authorRoiz et al. 2015. Plos One PASSER DOMESTICUS

ESCMID eLibrary © by author 45 sampling sites

ESCMID eLibrary © by author 3 TYPES OF HABITAT Natural - meadow

Rural - horse farm ESCMID eLibrary © by author 3 TYPES OF HABITAT Natural - meadow

Urban - village Rural - horse farm ESCMID eLibrary © by author MOSQUITO SAMPLING

April – December Sampling every 45 days BG traps 335.000 female mosquito captured

ESCMID eLibrary © by author BIRD SAMPLING House sparrows July - October 2013 Daily sampling

Serum WNV

MOST COMMON MOSQUITO SPECIES

Culex theileri - 282,891 Ochlerotatus caspius - 21,155 Culex pipiens - 19,268 Culex perexiguus - 5,939 Anopheles atroparvus - 5,387 Culiseta annulata - 2,514 Ochlerotatus detritus - 1,495 Culex modestus - 1,237 CulisetaESCMID longiareolata - 476 eLibrary © by author 0.67% (0 - 8%) of the house sparrows sampled were positive to WNV antibodies.

ESCMID eLibrary © by author ESCMID eLibrary Martínez de la Puente et al. 2018. Scientific Reports © by author ESCMIDNumber of Culex perexiguus captured ineLibrary areas with and without WNV seropositive House sparrows, as determined by VNT. Martínez de la Puente et al. 2018. Scientific Reports © by author All positive cases of WNV-specific antibodies in bird sera were found in rural and natural habitats

(N=956, est=-1.89, z=1.88, p=0.06)

ESCMID eLibrary © by author All positive cases of WNV-specific antibodies in bird sera were found in rural and natural habitats

(N=956, est=-1.89, z=1.88, p=0.06)

Mean: 77 (0-1424) people Mean: 0 people ESCMID> eLibrary WNV negative cases in birds WNV positive cases in birds © by author Conclusions

• WNV is endemic in many places in Europe

• Culex perexiguus, Culex pipiens and Culex modestus are important vectors of the virus in Europe

• In Spain, WNV is circulating mainly in Culex perexiguus, that fortunately not lives close to humans ESCMID eLibrary © by author Our group research is funded by:

EuroWestNile European West Nile R&D collaborative project