Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Scientists Testing Early Warning System for West Nile Virus

02.11.2012
When weather radar shows a funnel cloud, the tornado sirens howl, and folks run for cover. With outbreaks of West Nile virus, it’s not that simple.

Michael Wimberly, senior scientist at the Geographic Information Science Center of Excellence at South Dakota State University, has begun testing an early warning system for West Nile virus. Through a grant from the National Institute of Allergy and Infectious Diseases, Wimberly has analyzed satellite imaging data from 2000 to the present day to build a store of information to predict the future.

Key collaborators in this interdisciplinary effort include professor Mike Hildreth in biology and microbiology, associate professor Yi Liu in electrical engineering and computer science, and Ting-Wu Chuang, a former postdoctoral researcher now at Taiwan Medical University. Wimberly and Chuang recently published their findings on climatic variability and West Nile virus outbreaks in the northern Great Plains in the journal PLOS ONE.

“My first forecast in 2010 was completely wrong,” he said. An early spring led to a prediction of an active year for West Nile virus, but the opposite was true.

“What we’re doing is unique,” Wimberly said. “We are trying to make a much tighter link from research to application.” To do this, he has been working closely with the S.D. Department of Health and the state epidemiologist.

After his first attempt, Wimberly developed more sophisticated models and predicted a low risk of West Nile infections for 2011. This time he was right.

Temperature strong indicator
“Our research has shown if we look broadly at a regional level, temperature is an extremely strong driver,” he said.

Wimberly found associations between West Nile virus and temperature at two different times of the year. First, an earlier spring green up, like this past year with the warm April, gives the virus a longer amplification period, he said. “In general, mosquitos develop more rapidly, are more active and tend to bite more when it’s hotter.”

Since the virus originates in the bird population but is transmitted to humans through a mosquito, an early spring alone is not a sufficient predictor. Wimberly explained that the Culex tarsalis mosquito must first bite an infected bird to acquire West Nile, and then the virus must incubate in the mosquito.

“The blood goes into the stomach,” he said, but in order for the mosquito to transmit the disease, the virus must reach its salivary glands. This process is also temperature dependent.

“The warmer it gets, the shorter the amount of time it takes for the mosquitos to become infectious,” Wimberly said. Consequently, a warmer than normal summer will accelerate the transmission from mosquitoes to humans.

In 2010, the population of the West Nile-carrying mosquitos was high, Wimberly explained. Yet the expected outbreak never occurred because of the cooler temperatures that summer. Despite the high mosquito numbers, very few were infected with the West Nile virus.

Moisture, more complicated.

Determining the virus’ relationship with moisture and rainfall is more complicated, Wimberly said. Mosquitoes need water to breed; therefore, people assume that areas experiencing a drought will have a reduced risk of West Nile virus.

“There is a tendency to assume a linear relationship with rainfall and mosquitos,” Wimberly said, but it’s more complex than that.

“Culex tarsalis are not flood water mosquitoes, so they don’t respond to rainfall with a huge breeding generation,” he said. The West Nile carriers are selective, preferring grass in roadside ditches, wheel ruts in a pasture, and irrigated alfalfa as a breeding ground. Wimberly called it the “Goldilocks effect--the water needs to be just right.”

After dramatic declines in the incidence of West Nile in 2010 and 2011, some researchers thought the virus had become less virulent and was fading away, Wimberly explained. Others believed that the bulk of the population had already been infected without having major symptoms and were already immune.

Enter 2012, the deadliest West Nile season ever.

Wimberly submitted his forecast for 2012 before the season began, and using a temperature-driven model, he predicted a high risk for West Nile outbreaks in South Dakota.
“You don’t hope you’re right; you don’t want a disease outbreak,” Wimberly said.

But he was right.

Model, a work in progress
Wimberly explained, “You fit a model, use it to make a forecast and put it out there and then evaluate the forecast and see where it’s right and wrong.” But to perfect the model, he said, “you have to be in the game for the long term.”
To do this, Wimberly has applied to the National Institutes of Health for an extension of the four-year grant which began in 2008. His next step will be to incorporate more information to do risk mapping, identifying places where transmission risk is highest.

“Over time, we get better,” Wimberly said, and as a result, the public health community will begin to trust the forecasts.

Though sirens might not sound to warn about West Nile virus, Wimberly’s forecasts may one day offer a warning to take precautions to avoid contracting the disease.

About GIS
The Geographic Information Science Center of Excellence (GIScCE) is a collaboration between SDSU and the U.S. Geological Survey's Earth Resources Observation and Science (EROS) Center. The GIScCE enables South Dakota State University faculty and students to collaborate with EROS scientists to conduct research, seek professional development, and implement educational programs in the field of geographic information science.

About South Dakota State University

Founded in 1881, South Dakota State University is the state’s Morrill Act land-grant institution as well as its largest, most comprehensive school of higher education. SDSU confers degrees from eight different colleges representing more than 175 majors, minors and specializations. The institution also offers 29 master’s degree programs, 12 Ph.D. and two professional programs.

The work of the university is carried out on a residential campus in Brookings, at sites in Sioux Falls, Pierre and Rapid City, and through Cooperative Extension offices and Agricultural Experiment Station research sites across the state.

Michael Wimberly | Newswise Science News
Further information:
http://www.sdstate.edu

Further reports about: Dakota EROS Excellence Award Nile Delta SDSU Science TV Virus West Nile virus educational program

More articles from Life Sciences:

nachricht Perseus translates proteomics data
27.07.2016 | Max-Planck-Institut für Biochemie

nachricht Severity of enzyme deficiency central to favism
26.07.2016 | Universität Zürich

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Self-assembling nano inks form conductive and transparent grids during imprint

Transparent electronics devices are present in today’s thin film displays, solar cells, and touchscreens. The future will bring flexible versions of such devices. Their production requires printable materials that are transparent and remain highly conductive even when deformed. Researchers at INM – Leibniz Institute for New Materials have combined a new self-assembling nano ink with an imprint process to create flexible conductive grids with a resolution below one micrometer.

To print the grids, an ink of gold nanowires is applied to a substrate. A structured stamp is pressed on the substrate and forces the ink into a pattern. “The...

Im Focus: The Glowing Brain

A new Fraunhofer MEVIS method conveys medical interrelationships quickly and intuitively with innovative visualization technology

On the monitor, a brain spins slowly and can be examined from every angle. Suddenly, some sections start glowing, first on the side and then the entire back of...

Im Focus: Newly discovered material property may lead to high temp superconductivity

Researchers at the U.S. Department of Energy's (DOE) Ames Laboratory have discovered an unusual property of purple bronze that may point to new ways to achieve high temperature superconductivity.

While studying purple bronze, a molybdenum oxide, researchers discovered an unconventional charge density wave on its surface.

Im Focus: Mapping electromagnetic waveforms

Munich Physicists have developed a novel electron microscope that can visualize electromagnetic fields oscillating at frequencies of billions of cycles per second.

Temporally varying electromagnetic fields are the driving force behind the whole of electronics. Their polarities can change at mind-bogglingly fast rates, and...

Im Focus: Continental tug-of-war - until the rope snaps

Breakup of continents with two speed: Continents initially stretch very slowly along the future splitting zone, but then move apart very quickly before the onset of rupture. The final speed can be up to 20 times faster than in the first, slow extension phase.phases

Present-day continents were shaped hundreds of millions of years ago as the supercontinent Pangaea broke apart. Derived from Pangaea’s main fragments Gondwana...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

GROWING IN CITIES - Interdisciplinary Perspectives on Urban Gardening

15.07.2016 | Event News

SIGGRAPH2016 Computer Graphics Interactive Techniques, 24-28 July, Anaheim, California

15.07.2016 | Event News

Partner countries of FAIR accelerator meet in Darmstadt and approve developments

11.07.2016 | Event News

 
Latest News

Clone Wars – FLI researcher is honored with prestigious Sofja Kovalevskaja Award

27.07.2016 | Awards Funding

New approach for environmental test on livestock drugs

27.07.2016 | Ecology, The Environment and Conservation

Two neonicotinoid insecticides may have inadvertent contraceptive effects on male honey bees

27.07.2016 | Agricultural and Forestry Science

VideoLinks
B2B-VideoLinks
More VideoLinks >>>