Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Effects of Climate Change on West Nile Virus

10.09.2013
The varied influence of climate change on temperature and precipitation may have an equally wide-ranging effect on the spread of West Nile virus, suggesting that public health efforts to control the virus will need to take a local rather than global perspective, according to a study published this week in the scientific journal Proceedings of the National Academy of Sciences.

University of Arizona researchers Cory Morin and Andrew Comrie developed a climate-driven mosquito population model to simulate the abundance across the southern United States of one type of mosquito known to carry and spread West Nile virus to humans.


Known as a vector for the West Nile virus, this Culex quinquefasciatus mosquito has landed on a human finger. Eliminating puddles and small containers of water can greatly reduce this mosquito's population. (Photo: CDC/Jim Gathany)

They found that, under the future climate conditions predicted by climate change models, many locations will see a lengthening of the mosquito season but shrinking summer mosquito populations due to hotter and dryer conditions allowing fewer larvae to survive.

However, these changes vary significantly depending on temperature and precipitation. For example, drops in summer mosquito populations are expected to be significant in the South, but not further north where there will still be enough rain to maintain summer breeding habitats and extreme temperatures are less common. These findings suggest that disease transmission studies and programs designed to control populations of disease-carrying mosquitos must be targeted locally to maximize their effectiveness, the authors argue.

"It used to be an open question whether climate change is going to make disease-carrying mosquitoes more abundant, and the answer is it will depend on the time and the location," said Morin, who did the study as part of his doctoral dissertation in the lab of Comrie, UA provost and professor in the UA's School of Geography and Development. Morin is now a postdoctoral researcher on Comrie's team.

"One assumption was that with rising temperatures, mosquitoes would thrive across the board," Morin said. "Our study shows this is unlikely. Rather, the effects of climate change are different depending on the region and because of that, the response of West Nile virus transmitting mosquito populations will be different as well."

"The mosquito species we study is subtropical, and at warmer temperatures the larvae develop faster," Morin explained. "However, there is a limit – if temperatures climb over that limit, mortality increases. Temperature, precipitation or both can limit the populations, depending on local conditions."

In the southwestern U.S. for example, hotter and drier summers are expected to delay the onset of mosquito season; however, late summer and fall rains are expected to result in a longer season. Conversely, the south-central U.S. will see fewer mosquito days due to less rain during summer and early fall. Higher temperatures projected for the shoulder seasons – spring and fall – will likely make for a longer mosquito season across much of the U.S., except in the Southwest during spring where severe drying inhibits population development.

Morin pointed out that while the study focused on one important part in West Nile virus' infectious cycle – mosquitoes of the species Culex quinquefasciatus – there are other mosquito species that transmit the virus. Furthermore, the virus also infects birds, another part in the cycle that was not included in the model simulations.

A so-called container breeder, Culex quinquefasciatus lays its eggs in small volumes of standing water. The larvae therefore depend heavily on precipitation, unlike species that prefer larger bodies of water such as lakes.

According to the Centers for Disease Control (CDC), 70 to 80 percent of people infected with West Nile virus do not develop symptoms. The remaining 20 percent will have flu-like symptoms for a week or two, while severe effects are limited to less than 1 percent of infected individuals. They include encephalitis (inflammation of the brain) or meningitis (inflammation of the lining of the brain and spinal cord) and mostly affect the elderly and individuals with compromised immune response.

First detected in North America in 1999, West Nile virus has since spread across the continental United States and Canada. Cases of humans infected with West Nile virus have been documented in every state in the contiguous United States. The areas of major epidemics vary from year to year. The largest most recent outbreak occurred in Texas in 2012, with 1,868 disease cases reported to the CDC.

"'Which locations are likely to experience epidemics in the future?' – those are the kinds of questions studies like ours may help prepare for," said Morin. "We don't model the actual virus, we only look at the vector, but our study informs at least one part of the ecology of the virus. It is unique in projecting the impacts of climate change on a West Nile vector."

Morin said the study could help managers and decision makers better anticipate how mosquito populations will respond to changes in climate and prepare accordingly.

"For example, if projected precipitation and temperature changes for a given area are indicating a longer mosquito season, public health officials can plan to adapt to that possibility through abatement and awareness campaigns.
This story and photos are online:
http://uanews.org/story/effects-of-climate-change-on-west-nile-virus
Contacts
Sources:
Cory W. Morin, 603-498-1246, cmorin@email.arizona.edu

Andrew C. Comrie, comrie@email.arizona.edu

UANews contact:
Daniel Stolte, 520-954-1964, stolte@email.arizona.edu

Daniel Stolte | University of Arizona
Further information:
http://www.arizona.edu
http://uanews.org/story/effects-of-climate-change-on-west-nile-virus

More articles from Studies and Analyses:

nachricht Europe’s Demographic Future. Where the Regions Are Heading after a Decade of Crises
10.08.2017 | Berlin-Institut für Bevölkerung und Entwicklung

nachricht Scientists reveal source of human heartbeat in 3-D
07.08.2017 | University of Manchester

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

A Map of the Cell’s Power Station

18.08.2017 | Life Sciences

Engineering team images tiny quasicrystals as they form

18.08.2017 | Physics and Astronomy

Researchers printed graphene-like materials with inkjet

18.08.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>