Ranchers and horse-owners who are concerned about the spread of West Nile Virus, but can't just change water in their animal's troughs every day have an important ally - fish.
Mosquito fish or feeder goldfish living in the troughs will eat the mosquito larvae, said Willis Lamm, president of Least Resistance Training Concepts, who also owns a ranch in Stagecoach.
"Just toss them into the tank and they stay there year-round," Lamm said.
There have been seven people in Lyon County diagnosed with West Nile virus this year, according to the state Health Division, and spokeswoman Martha Framsted said people should do whatever is necessary to avoid mosquitoes.
"We keep encouraging people to move that standing water or get the mosquito-eating fish," she said. "We are urging everyone to take preventive measures."
Lamm said the feeder goldfish are available at pet stores.
Mosquito fish are minnow-like fish that are available over the Internet, said Ed Foster, environmental science for the state Dept. of Agriculture.
"Mosquito fish will live in any standing water," he said. "But they can't make it through the winter in Northern Nevada, though it doesn't' matter because neither do the mosquitoes."
Lamm prefers feeder goldfish because they can survive the winter. "As long as you don't let the tank ice over, they will make it through the winter," he said.
Foster said Lyon County has had two birds that tested positive, one positive horse and 30 mosquito pools that tested positive for West Nile.
He said the mosquito pools are a unit of measurement for labs that test for West Nile in mosquitos. A pool consists of one to 99 trapped mosquitoes, which are then squished into a mash, put through a separation process. The next step is to add a serum, then expose the collection to heat. He said the tests are run daily.
"Horses are way down for West Nile this year," Foster said. "And Lyon is doing an excellent job of getting the samples."
Mike Holmes, the state Department of Agriculture's estray horse manager, said one mare in the Stagecoach area probably died as a result of West Nile Virus and her surviving foal tested positive for it. He added that disease was part of the natural balance of living wild, and there wasn't much that could be done about it. He added that this year West Nile has been less of a problem in the wild horse herds.
"Last year I had a lot more calls on it," he said.
Pam Zierenberg, a Central Lyon County Vector Board member, said the county treats the rivers in March with pesticide briquettes to kill the larvae, then does aerial sprayovers to kill the adult mosquitoes.
"We also have two fogging machines that spray specific areas, when someone calls in about a problem in a residential area," she said.
• Contact reporter Karen Woodmansee at kwoodmansee@nevadaappeal.com or 882-2111 ext. 351.
Fast facts
West Nile Virus
• Is spread through the bite of an infected mosquito
• Infects birds, horses and people
• Most who are infected never show symptoms
Tips on prevention
• Wear long pants and long-sleeve shirts when outdoors
• Use insect repellent that contains DEET
• Get rid of standing water where possible
• Don't go out at the dusk or dawn hours when mosquitoes are more active
• Avoid shaded areas during the daytime
By the numbers
Human exposures as of Thursday:
• Carson City - 4
• Churchill County - 4
• Clark County - 1
• Douglas County - 10
• Elko County - 10
• Humboldt County - 13
• Lander County - 1
• Lyon County - 7
• Pershing County - 1
• Washoe County - 4
Non-humans testing positive for the past week
County Mosquito pool Bird Horse
Carson City 0 1 0
Churchill 2 0 0
Clark 2 (1 suspect) 0 0
Douglas 1 1 0
Elko 14 (3 suspect) 0 2
Humboldt 3 0 1
Lander 1 (suspect) 0 0
Lyon 2 0 0
Pershing 1 0 0
Washoe 2 0 0
- Source: Nevada Department of Agriculture and the Nevada Division of Health