Surveillance and Epidemiologic Investigation
Surveillance activities measure
and monitor the impact of HIV and AIDS on disease incidence and mortality. An HIV
surveillance system continuously and systematically collects, analyzes, evaluates, and
disseminates data describing important health events of the HIV epidemic. Much of
surveillance focuses on case finding because it provides the data upon which other
activities and services (trend analysis, partner notification, early intervention and
prevention) are based.
Data gathered through surveillance:
- provides current information on the status of the
epidemic and the development of trends;
- indicates the magnitude and extent of medical, economic
and social impact and need;
- identifies levels and trends of HIV infection that are
necessary for developing, targeting, and evaluating both prevention and care and treatment
- provides information on which to base decisions about
policy development and resource allocation.
The history of AIDS/HIV surveillance in Wisconsin
In the early to mid-1980's, AIDS surveillance was strictly passive. It was
conducted by one individual on a case-by-case basis from reports submitted by physicians,
many who were seeing their first AIDS case. Because there was no approved test for HIV in
the early 1980's, cases were confirmed using clinical criteria based on a crude CDC case
In March 1985, the FDA approved the HIV enzyme
immunoassay (EIA) and Western blot test for screening blood products to ensure safety of
the blood supply. The test was quickly adapted in clinical settings and the Wisconsin
legislature enacted legislation in the fall of 1985 requiring all positive confidential
HIV tests be reported to the state epidemiologist. Wisconsin was one of the first three
states in the nation to enact such legislation. Simultaneously, the Wisconsin Alternate
Counseling and Testing Site (CTS) Program was established to defer persons at risk of HIV
infection from seeking testing at blood/plasma centers.
By the spring of 1986, the AIDS/HIV Program initiated
active surveillance with hospitals statewide and passive laboratory-based reporting. Over
time, surveillance data collection methods have been streamlined and automated. Sentinel
physicians and hospitals/clinics were identified and visited by surveillance staff to
strengthen the surveillance network and enhance reporting.
Confidential, name-associated reporting of confirmed HIV infection and AIDS to
the State Epidemiologist is required by Wisconsin statute (s. 252.15). Case reports are
submitted to the Wisconsin AIDS/HIV Program from private physicians, hospitals, clinics,
ambulatory care facilities, sexually transmitted disease clinics, the Wisconsin
correctional system, family planning clinics, perinatal clinics, Indian health clinics,
blood and plasma centers, military entrance processing stations, and laboratories
performing HIV testing.
Other sources of AIDS/HIV surveillance data include
state entitlement programs (AIDS/HIV Drug Assistance Program and AIDS/HIV Health
Insurance Premium Subsidy Program), tumor registry reports, ICD-9 discharge code reviews
conducted by the Bureau of Health Information and Policy, vital records death certificate
registry, and the tuberculosis (TB) registry.
AIDS and HIV reports are reported directly to the state
epidemiologist rather than local health departments. Case reports are usually received by
the Division of Public Health within one to two months of a physicians diagnosis.
Laboratory-based reporting is required by law.
Laboratories performing confidential name-associated HIV confirmatory testing (Western
blot, viral load, DNA PCR, CD4) report to the AIDS/HIV Program the name of the subject of
all positive samples and the name of the physician who ordered the test. This is useful in
identifying newly infected persons. The surveillance team uses these lists to ensure that
all case reports are received from clinicians.
Once collected, surveillance data is analyzed to define
the demographics of the epidemic in Wisconsin. This information can be used by prevention
staff to focus interventions, identify objectives for the HIV Prevention Planning Council,
identify trends, and provide essential data for program planning and resource allocation.
The numbers of cases of AIDS and HIV are also used to determine program funding from the
federal and state government.
Security of surveillance records has always been a
priority for the Wisconsin AIDS/HIV Program. Physical security measures have become
increasingly sophisticated through the use of automated technology that is integrated with
the security services of state law enforcement personnel. Written policies and procedures
ensuring security include annual in servicing of staff, locating staff who handle
patient/client data in a restricted area, and signed confidentiality assurances by
individual Program staff.
Surveillance staff continue to look for ways to improve
case-finding methods, increase onsite visits at clinical settings (especially outpatient
clinics), and investigate new technologies for efficiently managing highly confidential
For additional information regarding the surveillance
activities of the Wisconsin AIDS/HIV Program, contact Wendy Schell at
Last Revised: January 19, 2012