By Mosticare Editorial, 31 July 2026

Mosquitoes in Germany: the species, West Nile virus, and the real risk in 2026

Germany used to be the easy case. Mosquitoes were a summer nuisance at the lake and on the balcony, and the diseases they carry belonged to other countries. That description is now out of date. Germany has two separate mosquito stories running at the same time, and they involve two different insects, two different viruses, and two different parts of the country.

The first story is a native mosquito that already carries West Nile virus in the east of the country. The second is the invasive Asian tiger mosquito, which is spreading north and west and can carry dengue and chikungunya. This guide keeps the two apart, because confusing them is the fastest way to be both frightened and wrong.

The two mosquitoes that matter

Most of the mosquitoes that bite you in a German garden are native house mosquitoes of the Culex group, above all Culex pipiens. They are the ones at the pond at dusk, the ones that find the open bedroom window on a warm night, the ones that have always been here. They breed in standing water, they bite mainly from evening into the night, and until recently they carried no disease worth worrying about in Germany.

The second insect is new. The Asian tiger mosquito, Aedes albopictus, is small, black, and marked with bright white bands on its legs and a single white stripe down its back. It bites during the day, with a peak around dusk, and it breeds in tiny amounts of water in containers rather than in ponds. The ECDC factsheet records its body length at four to six millimetres and its flight range at a few hundred metres, which is why it is very much a mosquito of the garden, the yard, and the street where it hatched.

The important point is that the disease risk in Germany is split between these two. West Nile virus in Germany is spread by native Culex mosquitoes, not by the tiger mosquito. Dengue and chikungunya, if they ever transmit locally in Germany, would be spread by the tiger mosquito, not by Culex. Keeping the two vectors and the two virus families separate is the whole of an honest German mosquito briefing.

West Nile virus: already here, mainly in the east

West Nile virus is the part of the German picture that surprises people most, because it is not an import risk or a forecast. It is an established fact of the eastern German summer.

The virus arrived recently. Germany was considered free of West Nile virus until the hot summer of 2018, when the first infections appeared in birds and horses. The first human cases followed in 2019. Since then the Robert Koch-Institut has recorded between four and 35 locally acquired human infections in Germany every year. The peak year so far was 2024, with 35 human cases.

The 2025 season was much quieter. The Friedrich-Loeffler-Institut, which runs the national reference laboratory for the virus, confirmed only four horse cases and 21 cases in wild and zoo birds for 2025, and reported a similarly low human count, most likely because a cold, dry spring left far fewer mosquitoes than usual. So far in 2026 the RKI has recorded one locally acquired human case, to 29 July, with the transmission season only part way through. Year to year, then, West Nile virus in Germany runs hot and cold with the weather, but the baseline no longer returns to zero.

Geography matters more than the totals. Human West Nile infections in Germany cluster in the east: Berlin, Brandenburg, Saxony, Saxony-Anhalt and Thuringia are the recurring endemic states, with a first case reported in Bavaria in 2025. Berlin sits at the centre of this. The capital has recorded infected birds since 2018 and human cases since 2019, and research from the city has described the virus as having effectively settled into the local mosquito and bird population rather than arriving fresh each year. For a resident of Leipzig, Halle, Potsdam or Berlin, West Nile virus is now a normal, low-level feature of a hot summer.

What West Nile virus actually does

The reason for calm rather than alarm is in the clinical numbers. About 80 per cent of people infected with West Nile virus have no symptoms at all. Most of the rest have a short flu-like illness with fever, headache and aching limbs, sometimes called West Nile fever. Fewer than one in a hundred infections leads to the serious neuroinvasive form, which affects the brain and the nervous system and is the reason the virus is taken seriously in older and immunocompromised people.

The neuroinvasive share looks high in surveillance tables only because the mild and silent infections are never counted. There is no vaccine and no specific antiviral treatment for people, so the whole of prevention is avoiding bites during the July to September transmission window, when warm nights let the virus circulate. That is a point in favour of practical protection, not a reason for fear.

The Asian tiger mosquito: where it is, and where it is not

The second German story is the arrival of the tiger mosquito, and this is where public reporting most often runs ahead of the facts. It is worth being precise about where the insect is actually established.

The tiger mosquito has been arriving in Germany for years. The first eggs were found in 2007 at a motorway rest stop near the Swiss border, brought in along the transport routes from southern Europe. The first fully established population, with all life stages present, was confirmed in Freiburg in 2014. Since around 2019 the insect has settled into the warmer south and west: Baden-Wurttemberg, Bavaria, Hesse and Rhineland-Palatinate carry the longest-standing populations.

The newer front is the north and west. In North Rhine-Westphalia the state health office has recorded established populations in the south of the state since 2024, in and around Bonn and in the neighbouring districts of Euskirchen and the Rhein-Erft area. The city of Cologne, by contrast, has issued public warnings but has not confirmed an established local population, and it is worth stating that plainly: the tiger mosquito is expected in Cologne, it is not yet established there. Further east, an established population has been confirmed in Jena in Thuringia, and Berlin is now the northernmost point in Germany with a confirmed tiger-mosquito population. Many of these detections come through the citizen-science mosquito atlas, to which residents post specimens for identification.

The mechanism behind the spread is not mysterious. The insect travels along roads and railways as a stowaway, and milder German winters increasingly let the populations it drops off survive and breed the following year rather than dying out. Warm, wet summers of the kind Germany now has regularly are close to ideal for it.

What the tiger mosquito can and cannot do

The tiger mosquito is a competent vector for dengue, chikungunya and Zika, which is why its spread is watched so closely. That competence is a capacity, not an event. For local transmission to happen, an infected traveller has to be bitten by a local tiger mosquito, which then bites someone else, all inside the same small area and the same warm window.

As of 2026, no locally acquired dengue or chikungunya case has been documented in Germany. The imported cases arrive every year in travellers, but the onward local transmission that has produced small summer clusters in France and Italy has not yet been recorded on German soil. The honest framing is a rising but still unrealised risk: the vector is now present in parts of Germany, the virus arrives in travellers, and the two have not yet met at scale in a German summer. Prevention now is what keeps that gap open.

The real disease risk in Germany in 2026

Put the two stories together and the picture is specific rather than scary. In eastern Germany, West Nile virus is a real if low-level risk during high summer, spread by native mosquitoes, and worth respecting most if you are older or have a weakened immune system. In the south and west, and now in Berlin, the tiger mosquito is establishing itself and brings a future, not yet present, risk of dengue and chikungunya. Across the whole country, the everyday reality is still an itchy bite rather than an illness.

None of this calls for panic, and panic tends to send people towards the wrong tools. The evidence-based response is the same set of unglamorous measures that public-health agencies have recommended for decades, applied a little more seriously than Germany was used to.

Protecting a household, without fear and without gadgets

Protection against mosquitoes in Germany runs on three plain ideas: remove the water they breed in, keep them out of the rooms where you sleep and sit, and cover skin when you are out at their biting hours. Nothing on that list is exotic, and nothing on it plugs in.

Remove the standing water. Both German mosquito problems begin in water. Culex uses ponds, blocked gutters, rain barrels and any container left to fill; the tiger mosquito needs only a bottle cap's worth in a plant saucer, a watering can, a bucket or a clogged drain. Emptying or covering standing water around a house and garden once a week, through the summer, removes the breeding sites within the few hundred metres a tiger mosquito ever travels. It is the single most effective thing a household can do, and it costs nothing.

Keep them out of where you sleep and sit. A fine mesh barrier is the oldest and most reliable defence there is, because it works by geometry rather than by chemistry. A close-woven net over the bed, or fine-mesh screens on the windows, stops mosquitoes from reaching skin at night without putting anything into the air of a bedroom. For a warm German summer this has a second advantage: a mesh barrier lets a household sleep with the window open in a heatwave and still keep the Culex mosquitoes, and the West Nile risk they carry, on the far side of the mesh. An enclosed mesh space on a terrace or balcony does the same job for the evening outdoors, where the tiger mosquito bites.

Cover skin at biting hours, and use repellents as a supplement. When you are outside at dusk and after dark, long sleeves and long trousers cut the exposed area. On the skin that is left, the repellents that the evidence supports are DEET and picaridin, which the WHO lists among effective personal-protection measures. They are a supplement to the barriers and the water tipping, not a replacement for them, and they are most worth using in the eastern states during the West Nile season and around known tiger-mosquito areas.

The measures that are not on this list matter too. Ultrasonic plug-in devices, mosquito-repelling apps, citronella candles in the open air, and vitamin B supplements have no reliable evidence behind them, and time or money spent on them is time not spent tipping out the water or fitting the mesh.

Berlin and the bedroom

Berlin is the one German place where both stories overlap, and it makes the bedroom the front line. The capital has an established tiger-mosquito population and sits inside the West Nile endemic zone, and its hot, still summer nights are exactly when Culex mosquitoes carry the virus and when open windows invite them in.

The response is not to seal the windows and swelter. It is to put a physical barrier between the bed and the room air, so that the window can stay open for the heat while the mosquitoes stay out. A fine-mesh canopy over the bed, or fitted window screens, delivers both at once: cooler sleep and a lower bite risk, with nothing sprayed, plugged in or breathed. For a Berlin household during a July heatwave, that is the calm, correct version of taking West Nile virus seriously.

The terrace, the balcony and the garden

Outdoors, the tiger mosquito is the one to plan around, because it bites in the daytime and through the evening, exactly when a terrace or balcony is in use. Repellent on the skin helps, but the more comfortable answer for a fixed outdoor space is to enclose the seating area in fine mesh, turning a terrace or a balcony into a room the mosquitoes cannot enter. Combined with weekly tipping of every saucer, bucket and blocked drain within a few hundred metres, an enclosed outdoor space lets a household use the garden through a German summer without spraying anything into the air it breathes.

Frequently asked questions

Is West Nile virus really in Germany?
Yes. Germany has recorded locally acquired human West Nile virus infections every year since 2019, between four and 35 per year, with 35 in 2024 and a much lower count in 2025. The cases cluster in the eastern federal states, including Berlin, Brandenburg, Saxony, Saxony-Anhalt and Thuringia. It is spread by native Culex mosquitoes, not by the tiger mosquito.

How dangerous is West Nile virus?
For most people, not very. About 80 per cent of infections cause no symptoms, and most of the rest bring a short flu-like illness. Fewer than one in a hundred infections leads to the serious neuroinvasive form, which is the main concern for older people and those with weakened immune systems. There is no vaccine and no specific treatment, so avoiding bites is the whole of prevention.

Is the tiger mosquito established in Cologne?
Not as of 2026. The city of Cologne has warned that the tiger mosquito may spread there, but no established local population has been confirmed. In North Rhine-Westphalia the confirmed established populations are in the south of the state, in and around Bonn, Euskirchen and the Rhein-Erft area, present since 2024.

Can I catch dengue or chikungunya from a mosquito in Germany?
Not from local transmission so far. No locally acquired dengue or chikungunya case has been documented in Germany as of 2026. Cases in Germany are imported by travellers. The tiger mosquito that could in principle transmit them locally is now established in parts of the south, the west and Berlin, so the risk is rising, but it has not yet materialised.

What actually keeps mosquitoes away?
Three things with evidence behind them: tipping out standing water around the home every week, putting fine mesh between mosquitoes and the people who sleep or sit there, and covering skin plus using a DEET or picaridin repellent at biting hours. Ultrasonic devices, apps and vitamin B do not work.

When is the risk highest?
For West Nile virus, from July to the end of September, when warm nights let the virus circulate in Culex mosquitoes in eastern Germany. The tiger mosquito is active across the warmer months and bites in the daytime, with a peak around dusk.

The short version

Germany now carries two mosquito realities at once. In the east, and above all in Berlin, West Nile virus is an established low-level summer risk spread by native mosquitoes, serious mainly for the vulnerable and best met by not being bitten. In the south, the west and Berlin, the tiger mosquito is settling in and brings a future risk of dengue and chikungunya that has not yet arrived. The response to both is the same and it is undramatic: empty the standing water every week, put fine mesh between the mosquitoes and the people, cover skin at dusk, and leave the plug-in gadgets on the shelf.