Scientists say mosquito capable of spreading West Nile virus found in Switzerland

West Nile virus mosquito found in Switzerland

ZURICH — A mosquito capable of spreading the deadly West Nile virus to humans has been detected in central Europe for the first time, Swiss scientists said Friday.

The Asian rock pool mosquito — or aedes japonicus — has colonized an area of 1,400 square kilometers (540 square miles) in central Switzerland, Zurich University researchers said. They found the species in 122 of 3,500 locations tested over the past year.

“This is the first time we have proved that an invasive mosquito species is breeding and spreading in central Europe,” said parasite expert Alexander Mathis.

The Asian rock pool mosquito is native to Japan, Korea and China, but has also spread to North America. In western Europe, it has previously been detected in France and Belgium.

The U.S. Centers for Disease Control says lab experiments show the mosquito can transmit Japanese encephalitis and West Nile virus.

Both diseases can cause serious harm in humans and are potentially fatal. In the United States, West Nile virus infected more than 1,300 people and killed 44 last year.

In those areas where the Asian rock pool mosquito was detected it outnumbered the mosquito species most commonly found in Europe, the northern house mosquito or culex pipiens, Mathis said.

Unlike the northern house mosquito, which only preys on birds, the Asian rock pool mosquito draws blood from both humans and birds, who commonly carry West Nile virus, he said.

So far West Nile virus hasn’t been found in birds in central Europe, Mathis added, meaning there is currently no risk of human infection there.

But he said public health officials should consider taking measures to prevent the Asian rock pool mosquito from spreading.

Efforts are already under way in southern Europe to battle another foreign species, the Asian tiger mosquito. That species has been known to spread chikungunya fever — a virus which causes joint pain, headaches and rashes — and there are fears that it might be capable of transmitting more dangerous diseases like dengue and yellow fever.

The mosquito’s arrival has been blamed on international trade and travel, as well as global warming.