July 2009
With summer comes the threat of West Nile virus, spread by mosquitoes and capable of causing West Nile encephalitis, an infection that can result in an inflammation of the brain, in both horses and people. Horses are particularly susceptible to the disease. A West Nile virus exists for horses, which should be vaccinated before mosquito season starts and receive a yearly booster. Vaccination of horses is not a guarantee of protection against infection, and does not offer any protection for other animals or people.
Cutbacks in state funding for mosquito spraying will likely cause the local mosquito population to increase. The best method of prevention of infection with West Nile Virus for people and animals is to reduce the risk of exposure to the mosquitoes that may carry the virus, said Department of Environmental Protection Secretary John Hanger. Hanger said standing water can quickly become a breeding ground for mosquitoes. He asked all Pennsylvanians to follow the simple rule of dump it, drain it and treat it.
"Dump it if it has water in it; drain it if it can be drained; and treat it if it has standing water," said Hanger. "By taking these simple actions in your own backyard, you can eliminate those breeding areas and reduce the threat of contracting the virus." Certain mosquitoes species carry West Nile virus. According to the Centers for Disease Control and Prevention, all residents in areas where virus activity has been identified are at risk of getting West Nile encephalitis.
This year, Governor Edward G. Rendell proposed $4.6 million to battle West Nile. Currently, surveillance and control efforts are underway in all 67 counties, maintaining current levels of funding. However, a Senate-approved budget bill, Senate Bill 850, would reduce next year's funding by 40 percent to $2.8 million, and force DEP to consider eliminating counties from the program.
In addition, the Senate plan proposed to slash an additional $50 million from the Governor's proposed DEP budget of $210 million to $160.8 million. Such a cut would set the department back to the 1994 level, hampering the agency's ability to meet its mission of safeguarding Pennsylvania's health and natural resources. "Pennsylvania has a monitoring, surveillance and spraying program in place that has been proven effective in controlling mosquito populations and decreasing cases of West Nile, but the threat of disease still exists," said Hanger. "If we cut back our aggressive efforts to battle mosquitoes, we increase the risks of contracting this deadly disease." In 2003, the year before Pennsylvania integrated a pest management program that led to better identifying and controlling mosquito populations, the virus was detected in all 67 counties. There were 237 confirmed human cases with nine deaths. Since then, there have not been more than 25 confirmed human cases in any given year. Hanger said the West Nile virus was detected in 37 counties last year. There were 14 persons diagnosed with the disease with one confirmed death. The first positive result of 2009 was found in an American crow collected in Springettsbury Township, York County, on May 5. This is the second-earliest reported evidence of West Nile Virus in Pennsylvania since 2003, when West Nile virus was identified in late April of that year.
Reducing risk involves eliminating mosquito breeding sites to reduce the number of mosquitoes. Mosquitoes lay eggs and develop in stagnant water, so reduction of these sites involves eliminating stagnant water sources.
Tips to eliminate standing water include:
• Throw away tin cans, plastic containers, ceramic pots or similar water-holding containers that have accumulated on property.
• Pay special attention to discarded tires, which can hold stagnant water.
• Maintain drainage holes located on the sides of gardening containers that might allow enough water to collect for mosquitoes to develop.
• Clean clogged roof gutters as needed.
• Turn over plastic wading pools, wheelbarrows and birdbaths when not in use.
• Aerate ornamental pools or stick them with fish.
• Keep water in stock tanks and buckets fresh.
• Clean and chlorinate swimming pools that are not being used.
• Use landscaping to eliminate standing water that collects on your property.
Additional steps can be taken to reduce the likelihood of exposure of animals to adult mosquitoes:
• Avoid turning on lights inside the stable during the evening and overnight hours. Mosquitoes are attracted to yellow incandescent bulbs.
• If light is needed near the stable, place incandescent bulbs outside the stable to attract mosquitoes away from the horses. Black lights (bug zappers) don't attract mosquitoes well.
• Reduce the number of birds in and around the stable area. Eliminate roosting areas in the rafters. Certain species of wild birds are thought to be the main reservoir for the virus. (Although pigeons have been shown to become infected with West Nile Virus, they do not appear to act as reservoirs and therefore don't transmit the virus to mosquitoes).
• Periodically look around the property for dead birds, such as crows. Any suspicious birds should be reported to the Pennsylvania Department of Health at 1-877-PA-HEALTH. Use gloves to handle dead birds and place the birds in plastic bags, as directed by the Department of Health.
• Topical preparations containing mosquito repellents are available for horses.
• Fogging of stable premises can be done in the evening to reduce mosquitoes.
• Try to keep pets indoors during peak mosquito activity times (dusk and dawn). Don't rely on flea products to repel mosquitoes. Try to keep pets from eating dead animals.
For help in assessing mosquito exposure risks on your property and for suggested control practices, contact your county extension office, county Department of Environmental Protection, county Department of Health, or mosquito and pest control company. For more information, visit www.westnile.state.pa.us.
