The Evolving Geography of Malaria

How the worlds most ancient disease has developed over the last century.

The malaria parasite has been killing children and sapping the strength of whole populations for tens of thousands of years. It is impossible to calculate the harm malaria has done to the world – Bill Gates

Malaria is one of the oldest diseases in the world. It is an ancient killer, with the earliest evidence being mosquitoes carrying the parasite preserved in amber from over 30 million years ago. The strain of the disease that affects humans most likely evolved alongside us in Africa. It then accompanied us on the many great migrations humanity has made. Malaria came along for the ride as we populated every corner of the world.

 

Mosquitoes carrying the malaria parasite preserved in amber.

 

The parasite itself is an evolutionary marvel – it twists and turns around any obstacle that is thrown up against it. These obstacles range from host species extinction causing the parasite to develop in order to infect a new species of animal, to the problems faced by chloroquine resistance in the 20th century and the artemisinin resistance that is creeping up on South East Asia in the present day.

All civilisations in human history have dealt with malaria at some stage. Alexander the Great famously died of the disease, as did his Roman successors. Malaria was present for Genghis Khan, the conquistadores and colonialists in the Americas, and the soldiers in both world wars. However, we have entered an era where one civilisation now lives without fear of the parasite. The affluent west.

If you look at three diseases, the three major killers, HIV, tuberculosis and malaria, the only disease for which we have really good drugs is HIV. And it’s very simple: because there’s a market in the United States and Europe. – Jim Yong Kim

In the United Kingdom, malaria had been a problem for centuries. What some at the time described as « marsh fever » was actually a form of malaria. In the marshlands of Kent and Essex it was a particular problem come the summer months, and it is posited by medical historians to be a major cause of mortality up until the 19th century. By the 1950’s however, malaria had all but disappeared from England. This was as a result of approaches by Ronald Ross, who enacted the first anti-mosquito measures in England to combat malaria, and S.P James, who furthered these measures through his realisation that poor housing conditions and poverty were indirect catalysts for malaria infection. Once it was understood that poverty and malaria were interlinked, the transmission cycle for malaria was broken.

The United States also eliminated malaria in the mid 20th century, and like the United Kingdom the solution was to separate people from the mosquitoes that infected them by using labourers to dig drainage and a large scale deployment of insecticide. These measures, coupled with the improving standard of living in the United States, caused deaths from malaria to drop rapidly between the 1920’s and late 1940’s.

 

A graph depicting the decline of malaria in the United States.

What the United States and the United Kingdom have in common is that they were able to approach malaria elimination from a position of social and economic strength. Similar countries such as France, Italy and the rest of europe also struggled with malaria for centuries but managed to eliminate the disease because they managed to break the link between poverty and malaria. Whilst malaria is one of the worlds most ancient killers, it is merely a symptom of a wider disease – poverty.

Maps of malaria transmission worldwide in 1900 compared to 2011.

Across the developing world malaria tends to remain and in some cases, thrive. The parasite needs a conduit to move around continents as it has done in the past. An ideal condition for large scale outbreaks is large scale development. In the 17th century malaria was the main cause of death for the workers building the royal castle in the swamps of Versailles. The construction of the Panama canal also saw workers become infected and die from malaria, and modern industry is no different. Agricultural development in the highlands of Kenya acts as a terminal for malaria across the country. Workers travel from all around to work in the highlands, including some from Lake Victoria infected with malaria. This has previously caused the disease to explode throughout Kenya as when returning home, the workers bring the disease with them.

The ancient cradle of malaria was in Africa, and it is there that we see the hotbed of current cases, with a significantly higher death rate than anywhere else in the world. Part of the reason for this is that plasmodium falciparum, the deadliest form of malaria, is prevalent in Africa. The primary reason however is a lack of resources across the board that are needed to combat the disease. International aid efforts are vital in treating those that already have malaria and providing anti-mosquito measures where funding is available. The Bill and Melinda gates foundation has been instrumental in fighting to prevent the spread of artemisinin resistant strains and the cause against the disease globally. Sadly, the wider problem is not something that the west can simply throw money at. The problem comes back to breaking the back of the transmission cycle, which is not just a challenge for Africa geographically and environmentally, but politically and economically also.

This is why lowering the cost of diagnosing the disease is so important. If the diagnosis of malaria is cheap, accurate and accessible it has the knock on effect of saving money on the purchasing of anti-malarials. This will in turn free up money that could be used for developing infrastructure and moving human living conditions away from mosquito habitats. Mosquitoes can breed in something as simple as a pothole filled with rainwater, so even something as simple as investment in transport can contribute to driving down malaria cases.

Industry leaders also need a more efficient diagnostic tool for malaria. In order to boost productivity and succeed with large scale developments and operations, a healthy workforce is vital. Not only would businesses be able to provide rapid health care, they can use data taken from a digital diagnostic app or device in order to understand if malaria will be a problem on any given project. Freeing workforces, a key factor in the evolving geography of malaria, allows developing countries to develop faster. This can, in theory, provide an economy robust enough to take the measures that the western world have already put into place.

 

Malaria is preventable with the right means.

I saw an abstract this week in the Lancet Global Health journal dated to July 2013. The title of the article read: « Malaria Eradication: is it possible? is it worth it? should we do it? » Whilst the article was answering these questions intelligently, it would seem that alongside some of the groundbreaking technological innovations in the health field right now the answer to all three should invariably be yes. Is it possible? It was possible to eradicate malaria from marshes in Louisiana and deltas in the south of France, so yes. Is it worth it? The economic burden of malaria on developing countries hampers global trade, let alone the human cost of the disease worldwide, so yes. I think the last question « should we do it » is answered by the first two, and that answer is indeed, yes.