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News Release RI Department of Environmental Management 235 Promenade Street, Providence, RI 02908 (401) 222-2771 TDD/(401) 222-4462
DEM, HEALTH GEAR UP FOR MOSQUITO SEASON; PERSONAL PROTECTION AND LARVICIDING KEY Residents should, as part of their normal seasonal routine, protect themselves from exposure to West Nile Virus and EEE by avoiding mosquito bites and eliminating mosquito breeding grounds. At this time of year, they are urged to get rid of anything in their yards that holds standing water, such as old tires, buckets, junk, and debris, and to make sure their gutters are clean so that they drain properly. Mosquitoes breed in standing water. Just one cup of standing water can produce hundreds of mosquitoes. New This Year: Alternatives for Communities Personal protection and larviciding are the cornerstones of the state's mosquito response protocol, which has been updated to give communities a choice of larvicides for application in storm drains. DEM scientists continue to address a concern that the use of methoprene may have contributed to the decline of the lobster population. While laboratory studies do show that lobster larvae are affected by methoprene at levels above one part per billion (1 ppb) there is no evidence indicating that use of methoprene in catch basins has any impact on lobsters in the natural environment.* However, the Department is offering an alternative program for communities. They may elect to use Bacillus sphaericus (Bs), a naturally derived bacterium, in place of methoprene. There will be an opportunity for communities to discuss their individual situations with the Department. Director of Health David R. Gifford, MD, MPH and DEM Director W. Michael Sullivan, Ph.D. have today sent a letter to town officials addressing larvicides, the studies, and the real need for human health protection from West Nile Virus. "Our confidence is in the stability of methoprene staying in the storm drains," says Alan Gettman, Ph.D., DEM's mosquito abatement coordinator. "We have a much greater degree of assurance over a greater period of time. We don't have the same confidence in Bs, since it is likely to wash out of storm drains. Communities must re-treat after a heavy amount of rain." Human Health Protection Superb "Human health protection from mosquito-borne illness in Rhode Island has been superb over the past eight years," says Director of Health David R. Gifford, MD, MPH. "We attribute this to the excellent job that communities do in treating their storm drains, as well as to residents taking responsibility for their own personal protection." If preventative measures were abandoned, HEALTH would expect to see 10 new cases of serious West Nile Virus disease each year, resulting in around one death per year. Ten serious cases per year are only an estimate; actual counts could easily exceed ten in some circumstances, according to HEALTH officials. Of particular concern is the state's population of about 150,000 elders, the primary group at risk for serious West Nile Virus disease. There has been no change to the protocol's call for aerial or ground spraying. It will be recommended only when a team of mosquito control experts determines that the public is at substantial risk of contact by infected mosquitoes. DEM will distribute the larvicides Altosid (brand name for methoprene) to municipalities, on a date in May still to be determined, from the Department's supply depot in Cranston, for treating all public area catch basins. While Bacillus sphaericus (Bs) is a much less reliable product, it will be made available to communities opting for that product. Any community opting to utilize Bacillus sphaericus (Bs) must notify DEM's mosquito abatement coordinator, Alan Gettman, Ph.D, no later than Friday, May 16, since the Department would need to place an order for the product. Two identical mosquito control training sessions will be held by DEM on May 22 and May 28 at East Farm at the University of Rhode Island for municipal and state workers who will be applying larvicide. As in past years, DEM will trap mosquitoes on a weekly basis throughout the state beginning during the first week of June. The mosquitoes will be tested at the HEALTH laboratory, and DEM will provide, at minimum, weekly updates on test results to the media, with additional reports as necessary. Positive results will generally trigger additional trapping to assess risk. Tips for Horse Owners Because horses are susceptible to West Nile Virus and EEE, Rhode Island horse owners should vaccinate their horses early in the season and take measures to control and prevent mosquito exposure. Those controls should include: removing or covering all areas where standing water can collect; applying mosquito larvicide in appropriate locations; and avoiding turning animals outside at dawn, dusk, and during the night when mosquitoes are most active. Horse owners should insect-proof facilities where possible; use approved repellants frequently; monitor animals for symptoms of fever, incoordination, stumbling, and neurological signs; and report all suspicious cases to a veterinarian immediately. 2007 Rhode Island Roundup Last year, in Rhode Island, five mosquito pools tested positive for West Nile Virus, and no mosquito pools tested positive for EEE. There were no reported human cases in Rhode Island; however, state officials received reports of a visitor from the United Kingdom who was diagnosed with EEE after returning home from a six-week visit to Rhode Island and New Hampshire. The Viruses EEE, a cyclical virus, while not nearly as common as West Nile Virus, has a higher fatality rate. It is a viral disease contracted through the bite of an infected mosquito. In most years, the virus is limited to native bird populations and bird-biting mosquitoes, but occasionally the virus can be transmitted to humans and domestic animals. EEE virus affects the brain with symptoms that appear 5 to 15 days after being bitten by an infected mosquito. Symptoms may include high fever, headache, stiff neck and decreased consciousness. Up to 50 percent of cases may result in fatality. Individuals with symptoms suggestive of EEE should contact their physician immediately. West Nile Virus is also a mosquito-transmitted, viral disease that causes encephalitis. However, mortality rates are much lower than those of EEE. Most people bitten by WNV-infected mosquitoes do not get sick. However, the elderly and people with weakened immune systems are more prone to infections. Symptoms begin 3-15 days after the bite from an infected mosquito. Symptoms may include fever, headache, nausea, rash, stiff neck, muscle weakness, and disorientation. Of cases with serious symptoms, about 10 percent result in fatality. West Nile Virus made its first appearance in the Western hemisphere, in the New York City area in 1999, and has since spread throughout the country. In 2007, more than 1,200 human cases of West Nile Virus were reported throughout the country, including 124 deaths. -30- *Among the best scientific information available is a recent PhD dissertation conducted by Dr. Mari Butler at the University of Rhode Island assessing methoprene levels in Point Judith Pond following the flushing of catch basins treated with methoprene. Of 12 water samples, two had detectable levels of 0.05 ppb and 0.06 ppb; the rest showed no detectable levels. Similar results were obtained via a 2006 study in Toronto, Canada, which found that releases of methoprene from the outfall of a treated stormwater system were in the 0.03 to 0.04 ppb range, well below EPA standards and not detrimental to lobsters or any other natural resource. Following the lobster die-off in Long Island Sound in 1999, Connecticut-based studies were conducted to determine if the die-off could have been due to mosquito-related pesticides; the studies found no connection. And, a DEM analysis of mortality rates between various life stages of lobster, including newly settled juveniles, does not indicate any impact of methoprene usage. |
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