Monday, July 11, 2005 | 10:55 a.m.
Raccoons, the cute masked bandits best known for knocking around trash pails late at night, could be more dangerous than they appear.
The Clark County Health District is warning of a new disease that can be spread by raccoons.
District technicians last week received confirmation from a state laboratory that several raccoons collected in Clark County tested positive for a parasitic roundworm. This is the second consecutive year that tests have found evidence of Baylisascaris procyonis, or raccoon roundworm, which can be transmitted to humans.
The raccoons were found in the Lake Las Vegas area, officials said.
While infection does not harm raccoons, in humans it can be potentially fatal. Symptoms include nausea, liver enlargement, loss of muscle control, coma and blindness, said Vivek Raman, an environmental health specialist with the health district.
"It definitely has some pretty severe symptoms," he said.
According to the Health District, 11 human cases of raccoon roundworm infection have been reported in the United States, four of them fatal, since 1980. Raman said no human infections have been noted so far in Clark County.
The U.S. Centers for Disease Control and Prevention reports few diagnosed cases -- there were 25 in 2003 -- but officials suspect cases may have been undiagnosed or diagnosed as something else.
There are no drugs that can kill the roundworm in the body, and the damage caused by the migrating larvae is irreversible. The roundworms develop to maturity in a raccoon's intestine, where they produce millions of eggs that are shed in droppings.
Human infection occurs when people inadvertently ingest roundworm eggs found in soil, water or other contaminated sources.
Raman said prevention is the key to avoid infection. The Health District is advising people to:
Raccoon droppings and material contaminated by the droppings should be removed carefully and burned, buried or sent to a landfill. Prompt removal of droppings should limit the risk of exposure and infection.
"Just like any disease, it's all about prevention," Raman said.
The evidence of infection in the raccoons showed up for the first time last year as part of a collaborative effort between the Health District and the U.S. Agriculture Department.
Raman said the roundworm infection could show up in raccoons found in any part of the county. He noted that while raccoons are not indigenous to the Las Vegas Valley, they are now found throughout the urban area because the animals have adapted to living near people.
Raman said many raccoons seem to live in the southeast part of the valley.
Geoff Schneider, a spokesman for the state Wildlife Department, said the state has not counted the number of raccoons in Clark County, but they are now found in urban areas, at Mount Charleston and near river areas such as Laughlin, the Meadow Valley Wash and Logandale.
Part of the spread has come as people have tried, often unsuccessfully, to keep the animals as pets.
"People have imported them to places, or they've escaped or been released," he said.
Raccoons can bring other kinds of disease and are particularly notable as a vector for rabies, Schneider said.
He said people should remember that raccoons are wild animals and should be treated that way.
"Stay away from them," Schneider said. "Do not feed them. Like any animal, if you feed them they will stay. Don't encourage them. Don't try to make a pet out of them."
For more information on the raccoon roundworm, call the health district at 759-0677.