Surveillance of hantavirus pulmonary syndrome (HPS)
In 1993, hantavirus pulmonary syndrome (HPS) was first recognized in what became known as the Four Corners outbreak in the southwestern United States.
HPS is caused by several species of hantaviruses that are carried by rodents. These viruses are distributed throughout much of North and South America.
In the early stages of the Four Corners outbreak, pathologic examination of autopsy tissues contributed to the overall characterization of the disease. During that time, pathologists also discovered that immunohistochemistry (IHC) was a reliable diagnosis method for the disease.
IHC also allows for simpler specimen handling and makes it possible to diagnose HPS cases that had been previously undiagnosed.
As a result, IHC became part of the national surveillance program and helped to define both the epidemiology and clinical spectrum of HPS. To date, previously unidentified cases have now been identified to as far back as 1959.