The Japanese Mosquito arrives in Navarra

The Japanese mosquito(Aedes Japonicus), Asian bush mosquito in English, is a species native to Japan and Korea that was detected in Europe (Normandy, France) in 2000. The first sighting in Spain was in the town of Siero (Asturias) in 2018. This September Enrique Baquero, researcher at the Institute of Biodiversity and Environment BIOMA, University of Navarra, has identified a specimen inside a building in Pamplona and in broad daylight.

"The advance of this mosquito is being slow but continuous towards the east of Spain and so far, in addition to Asturias, it had already been sighted in Cantabria and Guipúzcoa. And its expansion, as in the case of other invasive mosquito species, is mainly due to the movement of people and goods", he assures.

According to published studies consulted by the expert, the Japanese mosquito is more resistant than other species to the winter temperatures found in temperate regions, and the eggs resist freezing and desiccation, remaining inactive during the winter. In addition, says Enrique Baquero, this mosquito species has a higher tolerance to contamination in breeding sites, so they can potentially spread at a faster rate. "In temperate areas such as Navarra, adults will be present from early summer and will remain active until early autumn".

Vector competence in the transmission of West Nile virus (WNV), Dengue and Chikungunya has been demonstrated for this mosquito species. Because it is capable of transmitting these arboviruses - viruses that affect vertebrates - there is concern that it could become a public health problem, especially since it easily colonizes urbanized environments with high human density.

"In Navarra we have a large number of birds of prey and we are also in a funnel of migratory movement of birds, which increases the possibility of WNV transmission, since the presence of this new vector is added to that of a species already present, Culex pipiens, which is currently the usual vector for this virus," adds Enrique.

In a recent scientific review (Petersen et al. 2024), which assesses the potential risks of mosquitoes to human health, this mosquito is among the species most in need of vigilance, and it is stated that it poses a significant risk for the transmission of new viruses. Baquero stresses the importance of studying zoonoses -diseases transmitted from animals to humans- and the analysis of interactions between human populations and animal communities.

"BIOMA Institute researchers, in relation to our studies of Biodiversity, are always on the alert observing the arrival of new species of animals, in order to identify them and evaluate at a scientific level the consequences they may have for human health (One Health) and the importance for the environmental balance," he concludes.

Bibliographic reference
- Petersen , V., Santana, M., Karina-Costa, M., Nachbar, J.J., Martin-Martin, I., Adelman, Z.N., Burini, B.C. 2024 Aedes (Ochlerotatus) scapularis, Aedes japonicus japonicus, and Aedes (Fredwardsius) vittatus (Diptera: Culicidae): Three Neglected Mosquitoes with Potential Global Health Risks. Insects, 15, 600. https://doi.org/10.3390/insects15080600