Could climate change trigger the return of eradicated mosquito-related disease?

November 05, 2018

The largest ever study of the mosquito evolutionary tree, going back 195 million years, suggests that present-day climate change could result in the spread and return of dangerous mosquito-borne diseases to new places or areas where they had previously been eradicated, scientists are warning.

These diseases - including malaria, Yellow fever, Zika virus, and Dengue fever - cause millions of deaths each year. While many of these diseases have been eradicated from Europe and are under control in other parts of the world, resurgence is always possible.

New research from the Milner Centre for Evolution at the University of Bath, University of York and China Agricultural University, shows that the rate at which new species of mosquitos evolve generally increases when levels of atmospheric carbon dioxide are higher. This is concerning because the greater the number of mosquito species, the more potential exists for new ways of vectoring diseases, and perhaps for new variants of those diseases.

However the research showed that whilst there is a link between rising CO2 levels and mosquito diversification, the association is more complicated than previously thought, with other factors - such as the diversity of mammalian hosts - contributing to an increase in the species richness of mosquitos.

Professor Matthew Wills, from the University of Bath's Milner Centre for Evolution, said: "It's only the female mosquitos that take a blood meal, and they use the CO2 that mammals and other vertebrates exhale as a very general cue to locate their hosts. One line of thinking is that as ambient levels of atmospheric CO2 rose, as they have done in recent decades, mosquitos may have found it increasingly difficult to distinguish between the CO2 from their hosts and those background levels.

"Vision, body heat and other smells might then have become more important in locating their blood meals, but many of these cues tend to be more specific to particular hosts. As a general rule, we know that strong host specificity can be an important driver of speciation within parasites, and the same may be true in mosquitos."

Dr Katie Davis, from the University of York's Department of Biology, said: "We found that the increase in the diversity of mammals led directly to a rise in the number of mosquito species, and also that there is a relationship between CO2 levels and the number of mammal species, but there are still missing pieces of this puzzle, so we can still only speculate at this stage.

"It is important to look at the evolution of the mosquito against climate change because mosquitos are responsive to CO2 levels. Atmospheric CO2 levels are currently rising due to changes in the environment that are connected to human activity, so what does this mean for the mosquito and human health?

"Despite some uncertainties, we can now show that mosquito species are able to evolve and adapt to climate change in high numbers. With increased speciation, however, comes the added risk of disease increase and the return of certain diseases in countries that had eradicated them or never experienced them before."

Chufei Tang, formerly at the Milner Centre for Evolution and now at the China Agricultural University, said: "The rising atmospheric CO2 has been proven to influence various kinds of organisms, but this is the first time such impact has been found on insects. This research provides yet another reason for people to participate in low-carbon lifestyles."

More research is needed to understand what climate change means for the future of the mosquito and the work will contribute to further discussions about the value of the mosquito to the ecosystem and how to manage the diseases they carry.
-end-
The study, Tang et al (2018) "Elevated atmospheric CO2 promoted speciation in mosquitoes (Diptera, Culicidae)" is published in Communications Biology, DOI: 10.1038/s42003-018-0191-7.

University of Bath

Related Climate Change Articles from Brightsurf:

Are climate scientists being too cautious when linking extreme weather to climate change?
Climate science has focused on avoiding false alarms when linking extreme events to climate change.

Mysterious climate change
New research findings underline the crucial role that sea ice throughout the Southern Ocean played for atmospheric CO2 in times of rapid climate change in the past.

Mapping the path of climate change
Predicting a major transition, such as climate change, is extremely difficult, but the probabilistic framework developed by the authors is the first step in identifying the path between a shift in two environmental states.

Small change for climate change: Time to increase research funding to save the world
A new study shows that there is a huge disproportion in the level of funding for social science research into the greatest challenge in combating global warming -- how to get individuals and societies to overcome ingrained human habits to make the changes necessary to mitigate climate change.

Sub-national 'climate clubs' could offer key to combating climate change
'Climate clubs' offering membership for sub-national states, in addition to just countries, could speed up progress towards a globally harmonized climate change policy, which in turn offers a way to achieve stronger climate policies in all countries.

Review of Chinese atmospheric science research over the past 70 years: Climate and climate change
Over the past 70 years since the foundation of the People's Republic of China, Chinese scientists have made great contributions to various fields in the research of atmospheric sciences, which attracted worldwide attention.

A CERN for climate change
In a Perspective article appearing in this week's Proceedings of the National Academy of Sciences, Tim Palmer (Oxford University), and Bjorn Stevens (Max Planck Society), critically reflect on the present state of Earth system modelling.

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.

Read More: Climate Change News and Climate Change Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.