Mosquitoes are hitch-hiking across sub-tropical regions, according to scientists at the Smithsonian

Mosquitoes are hitch-hiking across sub-tropical regions, according to scientists at the Smithsonian

When it comes to travelling, it’s key that you remember to take with you all of your travel documents, your currency, your essential items and of course your suitcase. However, it may also be the case that you are bringing an unwelcome invader with you - in the form of a mosquito. Scientists at the Smithsonian Tropical Research Institute have found that mosquitoes are spreading to new places in the world, via a type of ‘hitch-hiking’.

The scientists have discovered that several species of mosquitoes are actually successful at sneaking into luggage, cars, trains and even planes - and ultimately travelling across tropical regions using humans as a sort of public transport system! As such, these species are now widely spread across many regions and are using their new found locations to spread their diseases, including dengue, chikungunya, and Zika.

Now, it is of course a wider scale problem than just the odd mosquito finding its way into an open car window... Findings show that many mosquito species actually came to new places on board trading ships, leaving their native countries as accidental stowaways and arriving in brand new places in the world. 

One of the biggest ways that this happens is through the trade of new and used tyres, as tyres are actually the perfect home for mosquitoes - as once the rain falls within the tyre, it’s difficult to remove with no natural run off, and it also has a shaded interior which maintains a steady temperature, so little water evaporates from these either. Once eggs have been laid inside, they can survive in their dried state while transported long distances along the roads in vehicles or on board ships. Upon reaching their destination, the addition of rainwater allows the eggs to hatch into immature mosquitoes, and starting their life in a new place as they then breed and hatch new babies as normal.

The species Aedes aegypti was the first to move, leaving Africa for the first time in the 19th Century, while Ae. albopictus only begun its worldwide invasion around 40 years ago, travelling from Asia with the trade of modern goods such as car tyres. They are so adept at this sneaky transportation because their eggs can survive and travel long distances, and they have also evolved to be specialists at living with people. 

These blood sucking mosquitoes feed on humans and now generally lay their eggs in man-made containers filled with fresh rainwater, such as plastic buckets, troughs or tubs, which provide a steady source of water even in the dry season. However, even if the water dries up, the hardy Aedes eggs have an incredible ability to survive in a desiccated state, hatching into aquatic larvae and emerging as adults, even after months with no rainfall. It’s this ability that permits Aedes mosquitoes to travel long distances, often assisted by people, enabling them to transport across the world and reach their new habitats. 

The movement of Aedes mosquitoes along the highways raises concerns when looking at ways to combat mosquito borne diseases, since the mosquitoes could be using these transport networks to exchange genetic material - creating new species of mosquito as they do so, some of which may exchange genes involved in insecticide resistance, or which can influence the ability of a mosquito to transmit or disseminate disease. 

It is clear, then, that mosquitoes are an ever growing problem in tropical regions, as they reach new areas and continue to create new species all of the time. Therefore, adequate mosquito protection for those travelling there is key. Make sure you check out our full range of effective, DEET and alcohol free mosquito repellent products over on the website.

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