From satellites in a low Earth orbit to predictive modeling software and geographic information systems, technology has taken a prominent role in the fight against West Nile virus and other mosquito-borne infectious diseases.

Experts are harnessing information technology to control pesticide spraying, provide online reporting capabilities and electronically exchange information among federal, state and local government officials. Local inspectors now carry personal digital assistants to record the latitude and longitude of possible mosquito breeding areas while NASA officials provide satellite observations to help forecast high-risk areas for mosquito-borne diseases.

Government officials and experts involved in mosquito control and West Nile virus prevention said IT is helping them better monitor, detect and prevent the spread of the disease each season.

"It's one of the big things right now in mosquito control," said Joe Conlon, a technical adviser at the American Mosquito Control Association, a nonprofit scientific and educational organization.

People are now getting doctorates in identifying habitats via satellite tracking, Conlon said. At its annual meeting this year, the 71-year-old association held a separate symposium on GIS and Global Positioning System technology for the first time. Previously, the subject matter was rather esoteric, he said.

Conlon said West Nile virus is the tip of an iceberg of potentially harmful infectious diseases, and technology helps officials remain vigilant in surveillance, detection and response. "This disease is not going to go away," he said.

From Uganda to the United States
West Nile virus, which scientists first isolated in Uganda nearly 70 years ago, was first detected in the United States in New York in 1999. A person infected with the arbovirus " a virus transmitted by an arthropod " can contract West Nile fever. Its symptoms include fevers, headaches, fatigue, aches and rashes.

But the virus can also threaten a person's nervous system. Such neuroinvasive diseases include West Nile encephalitis, which is an inflammation of the brain; West Nile meningitis, an inflammation of the membrane around the brain and spinal cord; or West Nile meningoencephalitis, an inflammation of the brain and surrounding membrane.

Most people infected with the virus show no symptoms, while about 20 percent will contract West Nile fever. Less than 1 percent will contract a neuroinvasive disease. Through 2005, the virus, which has spread across the continental United States, has accounted for 19,706 human cases and 785 deaths. In 2006, 901 cases and 31 deaths had been reported as of Aug. 29.

Since 2000, state health departments have been reporting human and animal West Nile cases through the Centers for Disease Control and Prevention's electronic-based Arbovirus Surveillance Network, or ArboNet, which collects and archives such data on several arboviruses. The data is available to state and local health departments almost as soon as CDC receives it.

Other federal agencies, including NASA and the U.S. Geological Survey, also use the data. USGS displays West Nile cases " and those of other diseases " reported in birds, humans, mosquitoes, chickens, horses and other mammals on up-to-date interactive online maps.

Although federal agencies are integral to collecting data about West Nile virus and other infectious diseases and showing their national spread, most disease prevention falls to state and local agencies.

Across to California
In California, West Nile has been detected in 49 of the state's 58 counties. In 2006, 117 human cases and two deaths had been recorded through August.

California health officials said they were working on West Nile even before the first case was recorded there in 2002. More than 60 local vector control or mosquito abatement agencies participate in the state's surveillance system, which involves surveillance and testing of humans, horses, mosquitoes, chicken flocks and other birds. Through active marketing, California encourages people to contact a toll-free hot line or Web site to report dead birds " often a good indicator of West Nile activity " or get information about the disease.

Stan Husted, supervising public health biologist at the Vector-Borne Disease Section of the state's Department of Health Services, said the hot line recorded 121,000 calls last year. This year, the state has recorded 40,000 calls through the hot line and received 5,000 dead-bird reports online, he said. The system enters the data into a SQL database that multiple hot line operators and other state officials can access.

State officials said the system classifies information by ZIP code so hot line operators can tell residents whether a local agency will be able to pick up dead birds for testing or whether they should dispose of them. The system also geocodes all reports so operators can immediately determine whether the location is valid.

Test results of birds are sent to the University of California at Davis' Center for Vectorborne Diseases, which can then quickly alert state and local officials via a password-protected electronic clearinghouse " the California Vectorborne Disease Surveillance Gateway " if they need to start emergency control procedures.

Ryan Carney, the health department's dead-bird surveillance program coordinator, said the gateway uses ESRI's ArcIMS product for real-time mapping of all surveillance elements, and agencies can query information and perform other functions. This year, the results are in real time, and agencies can also make PDFs of what they're viewing.

"It's the whole picture, a comprehensive view of what is going on throughout the state, and it gives agencies immediate perspective because it is mapped and in real time," Carney said.

State officials also expanded a test project this year called the California Dynamic Continuous-Area Space-Time (Dycast) program across the state. Developed in collaboration with Hunter College's Center for the Analysis and Research of Spatial Information, Dycast statistically analyzes dead-bird reports and places them in color-coded quarter-mile grids.

"It generates a probability index or a risk map, which shows the hot spots and peak activity," Carney said. "It looks at where dead birds are clustering in an episodic, relevant manner."

The procedure is run daily and helps agencies direct their surveillance efforts, control measures and public education. Carney said the tool is a rapid indicator of West Nile activity even before a dead bird is tested for the virus, which can take several days.

And down to the Florida Keys
The Florida Keys Mosquito Control District established an IT shop about five years ago in an effort to better coordinate its surveillance, detection and prevention efforts across the archipelago, which has a population of 80,000 and stretches 138 miles from the tip of Florida to Key West.

Ralph DePalma, the district's IT program manager, said the Florida Keys' mosquito population is profuse and the geography is not conducive to control measures that work in other counties.

Application of pesticides is highly regulated because many areas are national wildlife refuges, national parks, underwater preserves or sanctuaries.

Several years ago, the district invested in a CompassCom-developed automatic vehicle location (AVL) system and GPS to help manage and track the fleet of trucks and aircraft that spray pesticides.

Spraying has become more efficient and cost-effective because dispatchers are able to direct vehicles to the right locations, DePalma said. The district added a data communications application to the AVL system so employees can send information from the field in real time.

The district also established a large database of inspections and