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Domestic mosquitoes transmit dangerous diseases

Anyone bitten by mosquitoes is increasingly at risk of contracting dangerous diseases. This is the assessment of Doreen Werner, biologist at the Leibniz Center for Agricultural Landscape Research (ZALF) in Müncheberg near Berlin. Since the past year, it has been clear that it is not only immigrant exotic mosquito species that transmit pathogens such as Zika, Dengue or Chikungunya viruses. Scientists from the Friedrich-Loeffler-Institut (FLI) have also identified domestic mosquitoes as carriers of the West Nile virus, said the biologist, who works closely with the FLI.

Native species spread West Nile fever to humans

Native species would have transmitted West Nile fever to several people in Germany. This disease, originally from Africa, was previously known as an animal disease, especially in birds. Domestic mosquitoes would suck blood in birds as well as other vertebrates and humans, thus transferring the virus from one species to another.

According to the mosquito expert, climate change with the higher temperatures favors the spread of the virus , The warmer it is, the faster the virus in the mosquito grows and the risk of transmission increases.

The mild winter weather lures the first mosquitos outdoors. “From 6 to 7 degrees during the day, mosquitoes are on the move that have hibernated in attics, in basements, tree hollows or in piles of firewood,” says Werner. The starved females would bite to refill the blood.

Werner says of the diseases with the West Nile virus: “Domestic mosquitoes have been identified as carriers. They suck blood from birds as well as other vertebrates and humans. In this way, they can transmit the virus from one species to the other. ”

Mosquitoes as disease carriers become permanent problems

The actual animal disease, especially birds infected, also led to illnesses in humans. “The disease has no clear symptoms and can vary from mild nausea and headache to fever to severe neurological damage,” she said. The warmer it was, the faster the virus could multiply in the mosquito. “We assume that the West Nile virus will spread further through mosquitoes in Germany this year,” says the biologist.

With regard to global warming, the topic of “mosquitoes as disease carriers” is becoming a permanent problem in Germany, she estimates. Exotic invasive species, which spread further and could transmit tropical pathogens such as zika or dengue virus, also played a role, said the mosquito expert.

Evidence of a further establishment of these species is provided by, among others Mosquito Atlas, an internet portal for the spread of mosquito species that has been under construction since 2012. Everyone can catch mosquitoes in their living area and send them to the ZALF. The species is identified and mapped there.

Climate change is also noticeable in mosquitoes

The Asian tiger mosquito is thus establishing itself from the south. Populations in Bavaria and Baden-Württemberg are increasing. The Asian bush mosquito has only not yet arrived in Saxony, Brandenburg, Mecklenburg-Western Pomerania and Schleswig-Holstein. And Aedes koreicus, also called Korean bush mosquito, has established itself in Augsburg and Wiesbaden.

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Gefährliche Stechmücken - West-Nil-Virus in Deutschland

Dangerous mosquitoes – West Nile virus in Germany

In the past year, citizens have more than 14. 700 Caught specimens sent to Müncheberg. “In view of the rather anti-mosquito weather 2019 this is remarkable,” said Werner. She is currently determining the items found and entering them in the virtual atlas.

According to Werner, climate change is also noticeable in mosquitoes. The female animals needed moist breeding sites to lay eggs and thus reproduce. “The past two dry years have been poor in mosquitoes. Species that breed on flooded areas had bad cards, ”she says.

House mosquitoes usually start laying eggs in April

No matter how many Mosquitoes that had survived the winter, the weather conditions in the spring were decisive. House mosquitoes would usually start laying eggs in April. Despite the latest rainfall, there are currently hardly any potential breeding places such as puddles, filled rain barrels or flower vases. “Even field bunkers and forest ponds are partially completely dry because the water seeps away immediately.”

This development is alarming. “Even if we humans are happy if we don't have mosquitoes pissing on us, they are still important as food for birds, bats or other insects,” says the expert. This is also confirmed by Manuela Brecht from the Brandenburg State Association of the German Nature Conservation Association (Nabu). Dragonflies and fish would feed on mosquito larvae. Due to the drought, this food source is missing and causes, among other things, insect death. (AP)

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