Malaria, Zika and other potentially fatal tropical diseases could spread to Britain due to climate change, warns new research.
Currently, deadly illnesses spread by mosquitoes are confined to warm countries as the they can’t survive cooler weather.
But rising temperatures, combined with increasing international travel and trade, means they will reach northern Europe – including the UK.
This may led to a host of lethal insect borne illnesses – which also include chikungunya, dengue fever and leishmaniasis.
The virus encephalitis which can damage the central nervous system and is spread by ticks is already expanding rapidly.
Outbreaks are set to increase across much of Europe over the next few decades – and not just in the temperate countries around the Mediterranean.
Even previously unaffected areas in higher latitudes and altitudes, such as northern Europe, will be hit, warned scientists.
They called for improvements in surveillance and data sharing – along with better monitoring of the environment and climate – to combat the problem.
Professor Jan Semenza, of the European Centre for Disease Prevention and Control, based in Sweden, said: “Climate change is not the only or even the main factor driving the increase in vector-borne diseases across Europe.
“But it is one of many factors alongside globalisation, socioeconomic development, urbanisation, and widespread land-use change which need to be addressed to limit the importation and spread of these diseases.”
By 2040 the average daily temperature in the UK is expected to be between 0.5C and 1C hotter than today.
In February conditions hit a record 69.8F (21C) in West London, making it the first British winter to have ever passed 68F (20C).
The study, presented at the European Congress of Clinical Microbiology and Infectious Diseases in Amsterdam, said global warming has allowed mosquitoes, ticks and other disease-carrying insects to proliferate.
They have adapted to different seasons and invaded new territories across Europe over the past decade.
There have been cases of dengue in France and Croatia, malaria in Greece, West Nile Fever in Southeast Europe and the chikungunya virus in Italy and France. All are spread by mosquitoes – and are potentially fatal.
Dr Giovanni Rezza, director of the department of infectious diseases at the National Institute of Health, based in Rome, said: “The stark reality is longer hot seasons will enlarge the seasonal window for the potential spread of vector-borne diseases and favour larger outbreaks.
“We must be prepared to deal with these tropical infections. Lessons from recent outbreaks of West Nile virus in North America and chikungunya in the Caribbean and Italy highlight the importance of assessing future vector-borne disease risks and preparing contingencies for future outbreaks.”
The links between warming temperatures and international travel, weather sensitive pathogens and climate-change adaptions are complicated – making future predictions difficult.
The current crisis may only be the tip of the iceberg. Dr rezza said: “Mediterranean Europe is now a part-time tropical region, where competent vectors like the Tiger mosquito are already established.”
Hotter and wetter weather could provide ideal conditions for the Asian tiger mosquito (Aedes albopictus), which spreads the viruses that cause dengue and chikungunya, to breed and expand across the south and east of the UK, along with central Europe.
Previously dengue transmission was largely confined to tropical and subtropical regions because freezing temperatures kill the mosquito’s larvae and eggs.
But longer hot seasons could enable the insect to survive and spread across much of Europe within decades.
The European climate is already suitable for the transmission of Lyme borreliosis and encephalitis which are each spread by ticks.
There are an estimated 65,000 cases of Lyme borreliosis a year in the European Union, and a 400 percent rise in reported cases of tick-borne encephalitis in European endemic areas over the past three decades.
In the future, warmer winter temperatures, longer growing seasons, and earlier hotter summers could make conditions more favourable for ticks and increase the range of deer host populations.
Climate change models indicate that by 2040-2060, tick habits in Europe could grow by almost four percent, with Scandinavia most at risk.
Moreover, sandflies – the main carriers of Leishmaniasis which kills by destroying the immune system – may extend their geographical spread to southern parts of the UK, France, and Germany by the end of the 2060s.
Added Prof Semenza: “Given the ongoing spread of invasive mosquitoes and other vectors across Europe, we must anticipate outbreaks and move to intervene early.
“Public health agencies need to improve surveillance, for example through early warning systems, increase awareness of the potential risks among healthcare workers and the general public, as well as adopt innovative control strategies such as community interventions.”
The UK government announced a multi-million pound research fund last month to tackle the health effects of global warming.