[This story was edited Nov. 9 to correct the title of Dr. Ken Cox who is quoted in the story. He is medical informatics and special projects expert, U.S. Army Public Health].

Protecting the health and welfare of military veterans is the primary aim of the Department of Veterans Affairs. But making good on that mission is more than providing clinical services, hospital beds and pharmaceuticals to the sick and infirm. It also means knocking down health threats with sophisticated biosurveillance systems used to track diseases and infections.

From a national perspective, the Centers for Disease Control and Prevention also seek to monitor potential outbreaks of diseases such as pandemic influenza. And because veterans are numerous and spread out across the country, VA health data provides a vital input to the civilian public health picture. Together the CDC and the VA cover much of the waterfront of potential pandemic trouble spots.

"We send CDC a package of data that we collect on a nightly basis," said Dr. Mark Holodniy, director of VA's Office of Public Health Surveillance and Research, including demographic information and diagnostic codes relating to medical encounters. "The CDC has a group that collects this and other data in an effort to develop a situational awareness at the national level."

The data VA sends to CDC is derived from the VA's Electronic Surveillance System for Early Notification of Community- based Epidemics (ESSENCE), which monitors data from VA's VistA electronic health records at more than 150 veterans treatment facilities nationwide.

ESSENCE, originally developed by the Defense Department, detects disease outbreaks by applying software algorithms to medical data. For the last six years VA has been running a version of ESSENCE it acquired for its own use. The two are now merging their systems in order to provide each department with a broader public health picture. (See accompanying story.)

VA's Office of Public Health Surveillance and Research also is building a system focused on identifying and monitoring hospital-associated infections. Called the Healthcare-Associated Infection and Influenza Surveillance System (HAIISS), the system was built to streamline hospital care, identify drug resistant microbes and research the efficacy of antibiotics. (See sidebar.)

Guts of ESSENCE
ESSENCE is a Web-based application that monitors and provides alerts on rapid or unusual increases in the occurrence of infectious diseases and biological outbreaks. The system captures the numeric diagnostic codes entered into electronic health records and automatically collates that data among 10 categories of syndromes so public health officials can look out for outbreaks of diseases like pneumonia, influenza and food-borne illnesses.

"If the focus is on influenza, for example, the system will identify the number of cases in a specific location that showed up the day before and going back four weeks," said Dr. Ken Cox, medical informatics and special projects expert, U.S. Army Public Health. "Then it looks at those data and applies a statistical approach to determine whether the number of cases are more than would otherwise be expected."

The guts of ESSENCE is an extract, transform and load (ETL) package provided by Informatica, an enterprise data integration technology firm. The ETL tool makes sure that data loaded into the ESSENCE databases are clean, in the proper format and include all fields necessary for further processing. The data must also comply with privacy rules requiring the de-identification of records.

An Informatica tool called B2B is used to extract, transform and standardize unstructured data contained in a document, spreadsheet and messaging files and combine them with structured data extracted from electronic health records. Another Informatica tool, called PowerCenter, monitors databases to extract new information automatically.

Geospatial tools
Analysts also use tools from spatial data software maker ESRI to detect geographical patterns from among many thousands of seemingly random points of data. ESRI's ArcGIS system applies latitude and longitude data to patients' home addresses and displays symptomatic data outcomes in tabular formats for statistical analysis or graphically, by displaying the data on a map.

"Both the tables and the maps can help statisticians determine where concentrations of symptoms have occurred," said Bill Davenhall, ESRI's global marketing manager for health and human service solutions. "Without the geographical information you don't know whether you are seeing an outbreak or something random."

But public health officials do not rely on statistics alone to assess medical situations. "The statistics are always verified at the local level to determine whether it is a true outbreak or not," said Cox.

ESSENCE, block by block
Block One of ESSENCE, the version currently being run by VA and DoD, has three younger siblings in the development or planning stages.

Block Two, which will be introduced later this year, will detect evidence of flulike illnesses in addition to influenza itself by tracking data such as prescription of anti-viral medications. Block Two will also analyze lab orders in addition to the diagnostic data currently being crunched.

Block Three, which is in development, will add an analysis of a patient's chief complaint into the mix, a task which will present some challenges, according to Dr. Ken Cox, medical informatics and special projects expert, U.S. Army Public Health.

"This is not all captured as computable data," he said. "We will be using text parsers and natural language processors to look for key words."

A projected Block Four will analyze lab results. "That will lead us to where we are heading," said Cox, "the development of a fused detector algorithm instead of applying algorithms to separate data. We'll be able to sort data and post it on a dashboard."

SIDEBAR

Macro to micro surveillance

The health care advantages of early detection and treatment of oft-seen hospital-borne syndromes like bloodstream, surgical site and urinary tract infections and pneumonia are selfevident. But the trend is being pushed for financial reasons by health care insurers and government payors.

"A patient checks in for one day for a hernia operation, but ends up staying an extra 10 days for pneumonia he caught in the hospital," said Dr. Mark Holodniy, director of the Veteran Health Administration's Office of Public Health Surveillance and Research. "Why should we pay?" is the argument being heard from Medicare and other insurance programs.

The VHA is in the process of building a platform which seeks to provide a solution to this conundrum by identifying and tracking hospital associated infections and by studying antimicrobial usage and resistance. A pilot for the Healthcare-Associated Infection and Influenza Surveillance System (HAIISS) is already underway in the Veterans Hospital in Palo Alto, Calif., where Holodniy is stationed.

"We are trying to mitigate the additional costs and to prevent the morbidity, or sometimes the mortality, that results from these hospital infections," said Holodniy. "We also want to intervene early when infections are detected in order to avoid all of these downstream issues."

HAISS is powered by QC Pathfinder, a commercial software package from Vecna Technologies Inc., that uses data imported from VistA, the VA electronic health record, such as admission date, patient demographics, and selected clinical data, to detect infections and to analyze and diagram the types of bacteria present in a hospital.

QC Pathfinder's embedded algorithms are able to detect infections and categ