The aggressive nilfebersmyggan mosquito has been confirmed just north of Karlstad, marking its continued spread approximately 310 miles northward in Sweden since it was first detected in Skåne a decade ago, according to mosquito expert Anders Lindström at the Swedish National Veterinary Institute (SVA).
Lindström emphasized the public health significance of the finding, noting that the species, Culex modestus, can transmit viruses between birds and humans, making surveillance critical.
The mosquito, known to carry West Nile virus, was first identified in Sweden in early June 2016 when a specimen was captured in Skåne. While the virus can cause flu-like symptoms and, in rare cases, severe neurological inflammation in horses and humans, most infections are asymptomatic. A small number of cases may involve fever and flu-like symptoms, and in isolated instances, nervous system involvement can lead to fatalities.
Although there is currently no evidence of West Nile virus circulation in Sweden, outbreaks have occurred in other European countries including Hungary, France, and Italy, according to SVA.
Lindström, who discovered the mosquito when it attempted to bite him, stated that SVA researchers will now work to map the mosquito’s distribution to assess its prevalence. With this species now present, Sweden has a total of 50 species of stinging mosquitoes.
