Most feared species invading UK revealed as ‘yellow fever’ mozzies present in London

Government health chiefs have issued a warning after the ‘yellow fever’ mosquito was found breeding in homes in east London for the first time

A tropical-disease-spreading mosquito has been found breeding in the UK for the first time after health chiefs confirmed the invasive Aedes aegypti has turned up at homes in east London.

In a warning issued on Thursday (September 3), the UK Health Security Agency (UKHSA) said it is carrying out enhanced surveillance and trapping after Aedes aegypti mosquitoes and larvae were detected at residential properties.

The discovery was reported through UKHSA’s Mosquito Watch scheme and marks the first time Aedes aegypti – also known as the dengue or yellow fever mozzie – has been identified breeding in the UK.

Control measures have already been put in place to destroy the larvae and the area will be monitored closely to identify and eradicate any further mosquitoes. UKHSA said it runs programmes to monitor mosquitoes, providing early warning and supporting rapid public health action.

Dr Jolyon Medlock, Head of Medical Entomology and Zoonoses Ecology at UKHSA, said: “While Aedes aegypti can transmit diseases such as dengue, chikungunya and Zika virus in countries where these infections are circulating, the risk to the public from this finding is assessed as very low. There is no evidence that these mosquitoes have caused human infections and importantly, to date, there is no evidence of the mosquitoes or larvae being detected in nearby public areas.

“We believe these mosquitoes are accidental importations. Invasive mosquitoes can hitchhike in vehicles, baggage and imported plants, and if they find a suitable climate, can survive. Despite evidence of breeding in this local area and the recent heatwaves, the species is not established in the UK and cannot survive long-term in the typical UK climate, which is too cold overall.

“However, it is expected that in a warming climate, we will continue to see incursions of invasive mosquitoes, and increased reports of them being able to survive in the UK. As a precaution, residents can help reduce opportunities for all species of mosquitoes to breed by removing standing water from gardens and outdoor spaces, including water that collects in buckets, containers, paddling pools and plant pots.

“Members of the public can support mosquito detection through UKHSA’s Mosquito Watch scheme and submit photographs or specimens where possible. We will continue to monitor the situation closely.”

The warning comes as the UK is already home to more than 2,000 established non-native species, according to the GB Non-native Species Secretariat (NNSS), ranging from disease-carrying mosquitoes to destructive animals and plants.

Invasive species that have already been observed in the UK:

Asian Hornet

They are specialised predators of native honeybees and pollinators. A single hornet can consume dozens of bees a day, threatening the UK’s entire agricultural pollination system.

They are primarily concentrated in Kent, Sussex, Hampshire, and the Channel Islands, though tracking apps show them pushing further inland each summer.

Grey Squirrel

Introduced from North America in the 19th century, they carry the Squirrelpox virus. While immune themselves, the virus is fatal to native Red Squirrels.

They also strip bark from native trees, damaging woodland ecosystems. They are widespread and established across almost all of England, Wales, and Central/Southern Scotland.

Signal Crayfish

They escape from commercial farms, outcompete native white-clawed crayfish for food, and carry a deadly “crayfish plague”. They also burrow into riverbanks, causing severe erosion.

They are pervasive across major river networks throughout England and Wales, and slowly expanding into Scotland.

Killer Shrimp

Arriving via boat ballast water from Eastern Europe, these aggressive predators kill and alter the local ecology of native freshwater invertebrates without eating them. They are found in major reservoirs and water systems across Cardiff, Cambridgeshire, and the Midlands.

Japanese Knotweed

It has no natural predators in the UK. Its incredibly aggressive root system grows through tarmac, exploits cracks in concrete, and can structurally compromise buildings and flood defenses.

They are ubiquitous across the entirety of the UK, with heavy infestations in urban areas like Swansea, Bristol, and Greater London.

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