It kills more than 600,000 people every year and is coming to a water butt near you! Malaria. Once thought to be the result of “bad air” hence the name (mal=bad and aria = air) malaria is a well known cause of devastation in Africa, Asia and parts of America but we in the colder parts of the world have been largely protected. Aside from the many researchers here in the UK who are trying to understand and develop new preventatives and treatments, malaria has largely been a very sad thing that happens to others. Thanks to climate change we may not be as safe as we think.

Malaria is caused by a fascinating parasite called plasmodium (pronounced plaz-mo-deeum). There are in fact four parasites in the plasmodium family that commonly infect humans falciporum, vivax, ovale and malariae.

Falciporum is the most deadly, followed by vivax – these are the parasites that cause severe malaria, which often leads to a horrible death.

Plasmodium doesn’t infect humans directly, it needs a host to grow in – enter the mosquito.

Without mosquitos malaria would not exist. It isn’t just any mosquito either, the anopheles (pronounced an-off-ell-ees) mosquito, and only the female at that, is the vehicle malaria uses to get into our bodies.

The relationship between the malaria parasite and the mosquito is an intriguing one. In the same way as mosquitoes inject blood thinners to make sucking our blood easier, it seems that plasmodium may change the behaviour of mosquitos for its benefit.

Researchers have observed that mosquitos infected with malaria seem to be less selective about what animals they feed on. Sucking the blood of animals they would not normally prey on like hamsters.

Infected mosquitos also tend to feed for longer, almost like the mosquito is being controlled by the parasite to make sure it gets as much time to move from mosquito to human as possible.

Luckily for us we don’t have big populations of mosquitos. We live in a country that is cold – so fewer mosquitos breed. However, as climate has been changing, even the tiniest overall increases in temperature have caused the malaria map to spread.

The red region around the Equator that has traditionally been the malaria zone is bleeding outwards into new places. It won’t take a great temperature increase to see that danger zone starting to reach the UK. In addition we see that heavily populated areas such as cities tend to be hotter than rural areas. The so-called Urban Heat Island effect can increase temperatures in large cities by up to eight degrees.

Conveniently for mosquitos, cities are also places where more and more people are using garden water butts. With their standing water, that has collected bits of leaves and muck via your guttering, water butts make excellent mosquito farms.

These are early warning signs that we should be taking note of. It doesn’t mean we all have to move to Scotland (though I wouldn’t at all mind a life in the Highlands), we just need to be wary that a malaria outbreak in the UK is absolutely possible.