Nav: Home

Forecasting mosquitoes' global spread

March 04, 2019

Outbreaks of mosquito-borne illnesses like yellow fever, dengue, Zika and chikungunya are rising around the world. Climate change has created conditions favorable to mosquitoes' spread, but so have human travel and migration and accelerating urbanization, creating new mini-habitats for mosquitoes.

In today's Nature Microbiology, a large group of international collaborators combined these factors into prediction models that offer insight into the recent spread of two key disease-spreading mosquitoes -- Aedes aegypti and Aedes albopictus. The models forecast that by 2050, 49 percent of the world's population will live in places where these species are established if greenhouse gas emissions continue at current rates.

"We find evidence that if no action is taken to reduce the current rate at which the climate is warming, pockets of habitat will open up across many urban areas with vast amounts of individuals susceptible to infection," says Moritz Kraemer, PhD, of Boston Children's Hospital and the University of Oxford (UK). Kraemer was co-first author on the study with Robert Reiner of the University of Washington (Seattle), Oliver Brady of the London School of Hygiene and Tropical Medicine, Jane Messina of the University of Oxford and Marius Gilbert of the Universite Libre de Bruxelles (Belgium).

A spatial-temporal analysis

The team gathered historic data on the distributions of Aedes aegypti and Aedes albopictus over time in more than 3,000 locations in Europe and the U.S., going back as far as the 1970s and 1980s. They also mapped the locations based on their present-day suitability as mosquito habitats, then projected their suitability in 2020, 2050 and 2080 based on various climate models, projections of urban growth and other variables. They also included human migration and travel patterns, using data from census data and mobile phone records.

In recent times, they found, Aedes aegypti has tended to spread over long distances, while Aedes albopictus's spread has been more localized. Within the U.S., Aedes aegypti spread north at a relatively constant rate, about 150 miles per year. Aedes albopictus spread most quickly between 1990 and 1995; its advance has since slowed to about 37 miles per year. In Europe, Aedes albopictus has spread faster, advancing about 62 miles per year increasing to 93 miles per year in the past five years.

"We observed striking differences in the spread of both mosquito species, which has direct implications for surveillance and control strategies," says Kraemer. "We hope that these high-resolution maps will be used to target specific geographic areas for surveillance, control and elimination of these harmful mosquito populations."

What's next for mosquitos?

The models suggest that under current climate conditions and population densities, both mosquito species will continue to spread globally over the coming decades.

Aedes aegypti is predicted to spread mostly within its current tropical range, but also in new temperate areas in the U.S. and China, reaching as far north as Chicago and Shanghai, respectively, by 2050. In the U.S., this spread is expected to occur in large urban areas, through long-distance introductions of the insect. Aedes aegypti is expected to decline in the central southern United States and Eastern Europe, which climate models predict will become more arid. It's not expected to reach Europe except for parts of southern Italy and Turkey.

Aedes albopictus, however, is forecast to spread widely throughout Europe, ultimately reaching large areas of France and Germany over the next 30 years. It's also expected to establish a toe-hold in parts of the northern U.S. and the highland regions of South America and East Africa.

Climate change: the wild card

In the next 5 to 15 years, the models predict that spread of both species will be driven by human movement, rather than environmental changes. But thereafter, expansion will be driven by changes in climate, temperature and urbanization that create new mosquito habitats. And if climate change isn't curbed by 2050, the spread is predicted to be even greater.

"With this new work, we can start to anticipate how the transmission of diseases like dengue and Zika might be influenced by a variety of environmental changes," says Simon I. Hay, director of Geospatial Science at IHME and Professor of Health Metrics Sciences at the University of Washington. "Incorporating this information into future scenarios of risk can help policymakers predict health impacts and help guide strategies to limit the spread of these mosquito species, an essential step to reduce the disease burden."
Hay and Nick Golding of the University of Melbourne were co-senior investigators on the study. See the paper for a full list of authors and funders.

Boston Children's Hospital

Related Climate Change Articles:

Fairy-wrens change breeding habits to cope with climate change
Warmer temperatures linked to climate change are having a big impact on the breeding habits of one of Australia's most recognisable bird species, according to researchers at The Australian National University (ANU).
Believing in climate change doesn't mean you are preparing for climate change, study finds
Notre Dame researchers found that although coastal homeowners may perceive a worsening of climate change-related hazards, these attitudes are largely unrelated to a homeowner's expectations of actual home damage.
Older forests resist change -- climate change, that is
Older forests in eastern North America are less vulnerable to climate change than younger forests, particularly for carbon storage, timber production, and biodiversity, new research finds.
Could climate change cause infertility?
A number of plant and animal species could find it increasingly difficult to reproduce if climate change worsens and global temperatures become more extreme -- a stark warning highlighted by new scientific research.
Predicting climate change
Thomas Crowther, ETH Zurich identifies long-disappeared forests available for restoration across the world.
Historical climate important for soil responses to future climate change
Researchers at Lund University in Sweden, in collaboration with colleagues from the University of Amsterdam, examined how 18 years of drought affect the billions of vital bacteria that are hidden in the soil beneath our feet.
Can forests save us from climate change?
Additional climate benefits through sustainable forest management will be modest and local rather than global.
From crystals to climate: 'Gold standard' timeline links flood basalts to climate change
Princeton geologists used tiny zircon crystals found in volcanic ash to rewrite the timeline for the eruptions of the Columbia River flood basalts, a series of massive lava flows that coincided with an ancient global warming period 16 million years ago.
Think pink for a better view of climate change
A new study says pink noise may be the key to separating out natural climate variability from climate change that is influenced by human activity.
Climate taxes on agriculture could lead to more food insecurity than climate change itself
New IIASA-led research has found that a single climate mitigation scheme applied to all sectors, such as a global carbon tax, could have a serious impact on agriculture and result in far more widespread hunger and food insecurity than the direct impacts of climate change.
More Climate Change News and Climate Change Current Events

Top Science Podcasts

We have hand picked the top science podcasts of 2019.
Now Playing: TED Radio Hour

Why do we revere risk-takers, even when their actions terrify us? Why are some better at taking risks than others? This hour, TED speakers explore the alluring, dangerous, and calculated sides of risk. Guests include professional rock climber Alex Honnold, economist Mariana Mazzucato, psychology researcher Kashfia Rahman, structural engineer and bridge designer Ian Firth, and risk intelligence expert Dylan Evans.
Now Playing: Science for the People

#540 Specialize? Or Generalize?
Ever been called a "jack of all trades, master of none"? The world loves to elevate specialists, people who drill deep into a single topic. Those people are great. But there's a place for generalists too, argues David Epstein. Jacks of all trades are often more successful than specialists. And he's got science to back it up. We talk with Epstein about his latest book, "Range: Why Generalists Triumph in a Specialized World".
Now Playing: Radiolab

Dolly Parton's America: Neon Moss
Today on Radiolab, we're bringing you the fourth episode of Jad's special series, Dolly Parton's America. In this episode, Jad goes back up the mountain to visit Dolly's actual Tennessee mountain home, where she tells stories about her first trips out of the holler. Back on the mountaintop, standing under the rain by the Little Pigeon River, the trip triggers memories of Jad's first visit to his father's childhood home, and opens the gateway to dizzying stories of music and migration. Support Radiolab today at