London School of Hygiene & Tropical Medicine

A small number of eggs of the Aedes albopictus (or Asian Tiger) mosquito, which is capable of transmitting diseases including dengue, chikungunya and Zika have been found in the UK for the first time.

In recent years, there have been a number of exotic mosquitoes that have become established in Europe and Public Health England (PHE) conducts surveillance for invasive mosquitoes in the UK. It was through this routine surveillance that PHE confirmed eggs from Aedes albopictus in one trap in Kent.

Following the discovery, insecticide was used in the area as a precaution and PHE stated that 'enhanced monitoring of the area was implemented and no further evidence of this mosquito has so far been found.' They continue to monitor the situation closely and say there is currently no risk to public health in the UK.

How significant is the presence of these eggs and what level of response is required? Dr James Logan, Associate Professor of Medical Entomology at the London School of Hygiene & Tropical Medicine explains:

"There is a very low risk of disease transmission from these mosquitoes in the UK. Although the Aedes albopictus species is capable of transmitting viruses that cause diseases like dengue and Zika, importantly, not all mosquitoes of this species carry the viruses. The mosquitoes first have to be infected by biting somebody with the disease, which is extremely unlikely here in the UK. It is also worth noting that although Aedes albopictus may be involved in transmitting Zika virus, it is not the main vector in the current Zika outbreak - this is a different species - the Aedes aegypti mosquito.

"The discovery of these eggs is important but not unexpected. We have predicted that the Aedes albopictus mosquito species would enter the UK for some time and Public Health England has a surveillance system in place to detect imported species. It is important to note that this appears to be an imported case and we do not have evidence that this mosquito species has established itself in the UK. Mosquito monitoring has been increased in the area where the eggs were detected and mosquito control measures have been introduced as a precaution. As the weather turns colder this will also hinder further development of this species and cause mosquito populations in general to die away.

"There is a risk that more mosquitoes of this species could come to the UK in future. So, going forward, it is important that the government invests in creating enhanced surveillance and control measures for mosquito species that may be imported from other countries."

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