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9.5.2000 00:10
West Nile
virus kills
horse in
Wakefield
 The discovery means that the virus has spread to mosquitoes that bite humans.
By ARIEL SABAR
Journal Staff Writer
The first sign that mammal-biting mosquitoes in Rhode Island are carrying the West Nile virus surfaced yesterday, when state officials announced that a horse in South Kingstown had contracted the disease.
The discovery is the state's first evidence of the virus in mosquito species that bite human beings. Until now, officials had found West Nile only in dead birds.
State environmental officials said the results were not a surprise because they follow a pattern in other states of the virus emerging first in birds and then in mammals. Last fall, some 20 horses fell ill with the disease on Long Island, and 9 died. Last week, a horse with the virus in Bedford, Mass., showed severe neurological symptoms and was euthanized.
"This simply confirms what we had every reason to believe was true -- that at some level, we hope a low level, West Nile virus is now in mosquitoes that do bite people," said Malcolm J. Grant, the associate director for natural resources at the state Department of Environmental Management. "This should certainly get people's attention and, I would hope, raise their level of vigilance."
Local officials are planning to spray parts of South Kingstown and northern Narragansett with the pesticide Sumithrin starting at 7 tonight.
West Nile virus, which was first detected in the United States a year ago, crossed into Rhode Island last month. Since then, four birds have been found with the disease, and officials have sprayed sections of Cranston, Warwick, East Providence, Westerly, Middletown and Newport. There are plans to spray a section of Coventry tonight. The disease is spread by mosquitoes, which carry it in their salivary glands and pass it to other animals when they bite.
Because a number of mosquito species bite only birds, there was at least a theoretical possibility before now that the disease had not spread to mammal-biting mosquitoes. Still, state officials said yesterday that human infections were by no means a certainty, naming Massachusetts as a state where a horse was afflicted but humans have not gotten sick.
Anna F. Prager, a Town Council member in South Kingstown, said the discovery will mean lifestyle changes for a town checkered by brooks, marshes, walking paths and other
al fresco
spots favored by both mosquitoes and people. "I think it's going to put a damper on our enjoyment of our outdoors," Prager said yesterday. "The very things we value are all of sudden full of danger for us."
Prager said she has already changed her early-morning gardening ritual, now donning long pants, a long-sleeve shirt, a scarf, and a hat before watering her flower garden.
The infected horse, which had been stabled on Saugatucket Road in Wakefield, had fallen ill with symptoms of a neurological disorder. A local veterinarian referred it to the Tufts University School of Veterinary Medicine, in Massachusetts, where it was put to death on Aug. 28. A brain-tissue sample was sent to a U.S. Department of Agriculture veterinary lab in Ames, Iowa. The lab notified the Rhode Island environmental agency of its preliminary suspicions on Friday, and of its final results in a 10 a.m. phone call yesterday.
State officials said the horse hadn't been anywhere but South Kingstown in the past year, meaning that it contracted the virus there. The stable is in a rural stretch of the town, between Routes 1 and 108, covered with open fields and farmland. State officials would not disclose the exact location of the stable or the name of its owner, citing concerns about privacy.
Despite the discovery of the infected horse, scientists have yet to find any infected mosquitoes in the thousands they have been trapping since June -- a paradox that continues to befuddle state officials.
In humans, the West Nile virus can cause fever, headache, rashes and swelling of the lymph glands. In more serious cases, it can lead to a brain inflammation called encephalitis. According to the federal Centers for Disease Control and Prevention, the virus is fatal to humans in 3 percent to 15 percent of cases, most involving the elderly and others with weaker immune systems.
Officials suspect that the number of infections in Rhode Island is now peaking and will begin to diminish as the weather cools and mosquito populations dwindle.
Still, officials repeated warnings yesterday that Rhode Islanders use bug repellent with the chemical DEET, and avoid cool, moist and shady areas at dusk and dawn, when mosquitoes are most active.
Horses with West Nile virus typically show symptoms of anorexia, depression, listlessness, fever, and a range of other problems, from aimless wandering to paralysis of the lower lip. There are no documented cases of the disease spreading from horse to human, or from horse to horse. State officials recommended insect-proofing stables, applying repellents, and keeping horses stabled from dusk to dawn, when mosquitoes feed.
Researchers have found that cats and dogs are extremely unlikely to become ill from the virus. "People shouldn't be worried about their pets, unless their pets happen to be horses," said Grant, of the state environmental agency.
More details about the ground spraying are expected to be announced at an 11 a.m. news conference today at the South Kingstown Town Hall. Residents and their pets should stay inside at least 10 minutes after the spraying, and longer if possible. South Kingstown residents who want more information can call 789-9331, and Narragansett residents can call 782-0637.
Find out more about the West Nile virus
, from recent local news to information about the disease to official tracking reports, at:
http:/ projo.com/specials/westnile/
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