A mosquito species that can transmit potentially lethal tropical diseases such as dengue and Zika virus is breeding in the UK for the first time, health officials have found.
The UK Health Security Agency (UKHSA) today revealed the insects, known as Aedes aegypti, have been discovered at homes in east London.
Officials believe they landed in Britain ‘accidentally’ and suggested they may have hitchhiked from abroad in vehicles, bags or imported plants.
Aedes aegypti is native to Africa but has spread to a host of warmer climates in recent times including South East Asia, the Americas and Australia.
The discovery marks the fourth time the species has been detected in the UK, although it is the first time there has been evidence of it breeding here.
However, UKHSA chiefs believe the species won’t ‘become permanently established in England, and has not managed to survive the winter anywhere in northern Europe’.
But officials cautioned ‘mosquitoes can adapt quickly’ and, as temperatures rise every year in the UK, invasive species may become increasingly capable of surviving.
The warning comes just days after the Met Office said this year’s was the hottest-ever summer on record in Britain.
The UK Health Security Agency (UKHSA) today revealed the bugs, known as Aedes aegypti mosquitos, were discovered at residential homes in east London
Aedes aegypti can transmit several serious diseases through its bite, including dengue, which causes more than 12,000 deaths globally every year.
It can also spread yellow fever, which kills up to 82,000 people worldwide per year, as well as Zika virus and chikungunya.
Experts have consistently warned that such diseases could be on the rise in the UK thanks to rising temperatures potentially attracting more disease-carriers.
Health officials in France last week revealed they had seen 33 cases of chikungunya this summer driven by tiger mosquitoes, which were previously only established in the forests of South East Asia.
The UKHSA said measures have been put in place to destroy the mosquito larvae found at the properties in London. Officials will also continue monitoring the area, they added.
Dr Jolyon Medlock, head of medical entomology at UKHSA, stressed the risk to the public remains ‘very low’, with no evidence that the mosquitoes infected people. The insects have also not been found in public areas.
Dengue, zika and chikungunya can cause mild illness, triggering headaches, muscle aches and a rash
‘We believe these mosquitoes are accidental importations,’ Dr Medlock continued. ‘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.’
He added east London residents can take steps to reduce the risk of mosquitoes breeding in their gardens by removing water from gardens and outdoor spaces, including standing water in buckets, containers, paddling pools and plant pots.
Separate experts have said the risk to London residents developing serious disease from mosquitoes remains low. Those who’ve recently been bitten by a mosquito have also been told not to panic.
‘A mosquito bite in London does not mean that someone has been exposed to dengue, chikungunya or Zika,’ said Dr Cesar Lopez-Camacho, from the Nuffield Department of Medicine at the University of Oxford.
‘The current risk remains very low and there is no evidence of local transmission associated with this detection. For most people, a mosquito bite in the UK will simply result in the usual reaction such as itching, redness or mild swelling.
The biting insect has already spread across much of Europe in recent years – including in France , Spain and Italy – as warmer conditions have helped it travel
‘The situation is different if somebody develops fever or becomes unwell and has recently travelled to an area where dengue, chikungunya or Zika is circulating. In that situation, they should seek medical advice and make sure they mention their travel history.’
He added that the arrival of the species in the UK should be seen as ‘an early warning rather than an immediate public-health threat’.
‘We therefore should not be alarmist,’ Dr Lopez-Camacho continued, ‘but neither should we regard mosquito-borne viruses as exclusively tropical diseases. The epidemiology of arboviruses in Europe is changing.’
Other experts described the arrival of the mosquitoes as ‘concerning’.
‘We have seen an increasing number of locally acquired mosquito-borne infections across parts of Europe, including locally acquired chikungunya cases in France this summer,’ said Professor Trudie Lang, professor of global health research at the University of Oxford.
‘These diseases are usually limited to and associated with significant health impacts in tropical and subtropical regions, but that geographical distinction is becoming less clear.’
