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 How to become a T follicular helper cell
31.07.2015 | La Jolla Institute for Allergy and Immunology

nachricht Heating and cooling with light leads to ultrafast DNA diagnostics
31.07.2015 | University of California - Berkeley

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Quantum Matter Stuck in Unrest

Using ultracold atoms trapped in light crystals, scientists from the MPQ, LMU, and the Weizmann Institute observe a novel state of matter that never thermalizes.

What happens if one mixes cold and hot water? After some initial dynamics, one is left with lukewarm water—the system has thermalized to a new thermal...

Im Focus: On the crest of the wave: Electronics on a time scale shorter than a cycle of light

Physicists from Regensburg and Marburg, Germany have succeeded in taking a slow-motion movie of speeding electrons in a solid driven by a strong light wave. In the process, they have unraveled a novel quantum phenomenon, which will be reported in the forthcoming edition of Nature.

The advent of ever faster electronics featuring clock rates up to the multiple-gigahertz range has revolutionized our day-to-day life. Researchers and...

Im Focus: Superfast fluorescence sets new speed record

Plasmonic device has speed and efficiency to serve optical computers

Researchers have developed an ultrafast light-emitting device that can flip on and off 90 billion times a second and could form the basis of optical computing.

Im Focus: Unlocking the rice immune system

Joint BioEnergy Institute study identifies bacterial protein that is key to protecting rice against bacterial blight

A bacterial signal that when recognized by rice plants enables the plants to resist a devastating blight disease has been identified by a multi-national team...

Im Focus: Smarter window materials can control light and energy

Researchers in the Cockrell School of Engineering at The University of Texas at Austin are one step closer to delivering smart windows with a new level of energy efficiency, engineering materials that allow windows to reveal light without transferring heat and, conversely, to block light while allowing heat transmission, as described in two new research papers.

By allowing indoor occupants to more precisely control the energy and sunlight passing through a window, the new materials could significantly reduce costs for...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

3rd Euro Bio-inspired - International Conference and Exhibition on Bio-inspired Materials

23.07.2015 | Event News

Clash of Realities – International Conference on the Art, Technology and Theory of Digital Games

10.07.2015 | Event News

World Conference on Regenerative Medicine in Leipzig: Last chance to submit abstracts until 2 July

25.06.2015 | Event News

 
Latest News

Tool making and additive technology exhibition: Fraunhofer IPT at Formnext

31.07.2015 | Trade Fair News

First Siemens-built Thameslink train arrives in London

31.07.2015 | Transportation and Logistics

California 'rain debt' equal to average full year of precipitation

31.07.2015 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>