Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: SATURDAY, December 10, 1994 TAG: 9412120047
SECTION: VIRGINIA PAGE: B1 EDITION: METRO
SOURCE: BRIAN KELLEY STAFF WRITER
DATELINE: CHRISTIANSBURG LENGTH: Medium
Federal and state employees spent this week trapping mice along the Appalachian Trail from Giles to Roanoke counties in the hunt for the deadly, rodent-borne hantavirus, which infected a hiker 18 months ago.
Officials initially believed the Australian long-distance hiker was infected while staying at the Wapiti Shelter in Giles County - where two hikers were murdered in 1981 - or at a private hiker hostel south of Pearisburg, but have discarded those theories and cast a wider net.
"It's still more of a risk to drive on the interstate highway than to hike on the Appalachian Trail," said Dr. Suzanne Jenkins, assistant state epidemiologist in Richmond.
Tests conducted in 1993 found the virus in mice in Giles, Rappahannock and Madison counties. The University of Virginia's Mountain Lake Biological Station collected the Giles mice in 1993 as part of a national search for the hantavirus, Jenkins said.
The chances of contracting the virus are slim if hikers and others avoid touching mice feces or stirring up dust in an enclosed, mouse-infested area. The virus is contained in mice droppings, urine and saliva and can become airborne.
An expert with the U.S. Centers for Disease Control in Atlanta this week taught live-trapping and organ collection techniques to local Health Department sanitarians and National Park Service employees. They collected mice from Giles north on the trail into Roanoke County, as well as from off-trail locations.
"We don't know where this hiker was infected; it's just impossible to tell," said Dr. D. Craig Smith, acting director of the New River Valley Health District. "We may have some suspicions, but they're immaterial, really.
"Everybody feels like it was Virginia" where the hiker was infected, Smith said. "Pointing a finger in one direction or another wouldn't serve any purpose."
The mice-trapping ended Thursday. After placing traps in the evenings, workers collected them in the mornings and took the mice to an undisclosed location for processing. There, workers anesthetized the rodents, drew blood, then euthanized them and removed their organs for testing in Atlanta. The test results won't be in for six to eight weeks.
"That was done with full protective garb: positive air-purification system, gowns and masks, the whole bit," Smith said.
The tests, though, may give investigators a clue about where the hiker became infected in a process that's a bit like assembling a puzzle. There are several different strains of hantavirus. If a strain is found in the organs of one or more of the mice, researchers can test it with antibodies taken from the hiker's blood. If the antibodies react to any strains, it's more likely the hiker was infected wherever that particular mouse was taken.
An outbreak of the hantavirus killed 40 people in the Southwestern United States last year. Ninety-eight people have been infected nationwide. The Appalachian Trail case - only confirmed recently through follow-up tests with the hiker - is one of the handful recorded in the East.
The Australian hiker in his 60s - whose name officials have not released - became ill, left the trail and sought treatment in late June 1993 in Chambersburg in southern Pennsylvania. He spent nearly a month in a hospital recovering from serious complications to his lungs and other internal organs. He had hiked the 500 miles of trail in Virginia between mid-May and mid-June 1993. The incubation period for hantavirus ranges from three days to six weeks, but most of the time it is two weeks, Jenkins said.
Using the hiker's detailed diary and the usual incubation period, federal investigators first narrowed down the search to Giles County. But after reviewing a telephone interview with the man and learning that deer mice are endemic to Appalachian Trail shelters, Jenkins rejected pinpointing any specific location.
"This hiker did not like staying in buildings," Jenkins said. "We trapped mice in buildings. That doesn't mean we thought necessarily that he got infected there. He primarily slept in a tent or out in the open."
The symptoms of a hantavirus infection are flu-like, with fever, body aches, chills and difficulty breathing.
Now that a local team is trained, there may be more mouse collection and testing along the trail in Virginia, Jenkins said.
by CNB