Climate change is increasing the risk of malaria for people living in mountainous regions in the tropics

 

Science Editor

Millions of people living at higher altitudes in the tropics will be at risk of malaria as a result of rising temperatures and climate change, according to an analysis of the disease over the past two decades in two mountainous regions in South America and Africa.

Scientists found that when temperatures increased, malaria affected people at higher altitudes than when temperatures were cooler. It is the first study on the ground to show how temperature changes can affect the risk of malaria in populations living 1,200 metres above sea level.

Although researchers have long debated whether malaria will move as a result of climate change, this is one of the first studies showing that the disease does migrate higher when temperatures rise, which threatens the many millions of people who live in historically malaria-free regions of the high-altitude tropics.

“We have identified that malaria does indeed move up and down and that the movement is temperature dependent. It’s been difficult to prove and people have been questioning it now for 20 years,” said Menno Bouma of the London School of Hygiene and Tropical Medicine, who was part of the research team.

“The implications are that if this is true, and that a global warming is occurring leading to an increase in temperatures, then malaria will increase at higher altitudes where many people live. The high altitude areas in the tropics are particularly highly populated,” Dr Bouma said.

“They are more populated than the lowlands partly because there is more rainfall but also partly because there has been less malaria. They have been privileged places to live because of that, and many of these people have not been exposed to malaria and so will not be naturally protected against it,” he said.

The study, published in the journal Science, looked at malaria cases in the Antioquia region of western Colombia from 1990 to 2005 and the Debre Zeit area of central Ethiopia from 1993 to 2005. The researchers matched malaria outbreaks at various altitudes with temperature records to show how the disease rises and falls with warmer or cooler years.

Previous research in the Debre Zeit region of Ethiopia – where 37 million people live in rural areas at risk of higher malaria exposure under a warming climate – estimated that a 1C increase in average local temperatures will result in an extra three million children contracting malaria every year.

“Traditionally, we think of malaria as a disease with limited prevalence in highland regions, but we are now seeing a shift due to climate change. Our latest research suggests that with progressive global warming, malaria will creep up the mountains and spread to new, high-altitude areas. And because these populations lack protective immunity, they will be particularly vulnerable for severe morbidity and mortality,” Dr Bouma said.

Mercedes Pascual of the University of Michigan, a senior author of the study, said: “We saw an upward expansion of malaria cases to higher altitudes in warmer years, which is a clear signal of a response by highland malaria to changes in climate. This is indisputable evidence of a climate effect. The main implication is that with warmer temperatures, we expect to see a higher number of people exposed to the risk of malaria in tropical highland areas like these.”

Malaria, which infects more than 300 million people each year, is caused by a single-celled microbe called Plasmodium that is transmitted by the bite of a mosquito. Both the Plasmodium and the malaria-carrying mosquitoes thrive in warmer temperatures and so with rising temperatures can survive at higher altitudes that have traditionally been malaria-free.

Dr Bouma said that many millions of people in the tropics live at higher altitudes because they have been historically at lower risk of malaria and other tropical diseases. For instance, 43 per cent of Ethiopia’s population live in the Debre Zeit region, at an elevation of between 1,600 metres and 2,410 metres.

Start your day with The Independent, sign up for daily news emails
ebooks
ebooksA special investigation by Andy McSmith
  • Get to the point
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
Independent Dating
and  

By clicking 'Search' you
are agreeing to our
Terms of Use.

iJobs Job Widget
iJobs General

Ashdown Group: Senior Accounts Assistant - Accounts Payable - St. Albans

£26000 - £28000 per annum + benefits : Ashdown Group: Senior Accounts Assistan...

Ashdown Group: Treasury Assistant - Accounts Assistant - London, Old Street

£24000 - £26000 per annum + benefits : Ashdown Group: A highly successful, glo...

Recruitment Genius: Installation and Service / Security Engineer

£22000 - £40000 per annum: Recruitment Genius: This company is part of a Group...

Recruitment Genius: Service Charge Accounts Assistant

£16000 - £18000 per annum: Recruitment Genius: Are you a a young, dynamic pers...

Day In a Page

General Election 2015: Chuka Umunna on the benefits of immigration, humility – and his leader Ed Miliband

Chuka Umunna: A virus of racism runs through Ukip

The shadow business secretary on the benefits of immigration, humility – and his leader Ed Miliband
Yemen crisis: This exotic war will soon become Europe's problem

Yemen's exotic war will soon affect Europe

Terrorism and boatloads of desperate migrants will be the outcome of the Saudi air campaign, says Patrick Cockburn
Marginal Streets project aims to document voters in the run-up to the General Election

Marginal Streets project documents voters

Independent photographers Joseph Fox and Orlando Gili are uploading two portraits of constituents to their website for each day of the campaign
Game of Thrones: Visit the real-life kingdom of Westeros to see where violent history ends and telly tourism begins

The real-life kingdom of Westeros

Is there something a little uncomfortable about Game of Thrones shooting in Northern Ireland?
How to survive a social-media mauling, by the tough women of Twitter

How to survive a Twitter mauling

Mary Beard, Caroline Criado-Perez, Louise Mensch, Bunny La Roche and Courtney Barrasford reveal how to trounce the trolls
Gallipoli centenary: At dawn, the young remember the young who perished in one of the First World War's bloodiest battles

At dawn, the young remember the young

A century ago, soldiers of the Empire – many no more than boys – spilt on to Gallipoli’s beaches. On this 100th Anzac Day, there are personal, poetic tributes to their sacrifice
Dissent is slowly building against the billions spent on presidential campaigns – even among politicians themselves

Follow the money as never before

Dissent is slowly building against the billions spent on presidential campaigns – even among politicians themselves, reports Rupert Cornwell
Samuel West interview: The actor and director on austerity, unionisation, and not mentioning his famous parents

Samuel West interview

The actor and director on austerity, unionisation, and not mentioning his famous parents
General Election 2015: Imagine if the leading political parties were fashion labels

Imagine if the leading political parties were fashion labels

Fashion editor, Alexander Fury, on what the leaders' appearances tell us about them
Phumzile Mlambo-Ngcuka: Home can be the unsafest place for women

Phumzile Mlambo-Ngcuka: Home can be the unsafest place for women

The architect of the HeForShe movement and head of UN Women on the world's failure to combat domestic violence
Public relations as 'art'? Surely not

Confessions of a former PR man

The 'art' of public relations is being celebrated by the V&A museum, triggering some happy memories for DJ Taylor
Bill Granger recipes: Our chef succumbs to his sugar cravings with super-luxurious sweet treats

Bill Granger's luxurious sweet treats

Our chef loves to stop for 30 minutes to catch up on the day's gossip, while nibbling on something sweet
London Marathon 2015: Paula Radcliffe and the mother of all goodbyes

The mother of all goodbyes

Paula Radcliffe's farewell to the London Marathon will be a family affair
Everton vs Manchester United: Steven Naismith demands 'better' if Toffees are to upset the odds against United

Steven Naismith: 'We know we must do better'

The Everton forward explains the reasons behind club's decline this season
Arsenal vs Chelsea: Praise to Arsene Wenger for having the courage of his convictions

Michael Calvin's Last Word

Praise to Wenger for having the courage of his convictions