May/June 2003 Vol. 5, No.3

How to avoid West Nile Virus when gardening

As summer approaches and we find ourselves spending more time outdoors, we should also know how to protect ourselves and our families against the West Nile virus.

The West Nile virus is spread through the saliva of infected mosquitoes. It's then transmitted to humans, birds and horses. Symptoms include fever, headaches and body aches, usually lasting for a few days.

The good news is that less than 1 percent of mosquitoes carry the virus, and less than 1 percent of the people or animals bitten by an in-fected mosquito ever develop symptoms of the disease. When detected early, most people have a good chance of recovery. On the other hand, this virus can be fatal. In rare cases, the disease can lead to permanent neurological problems.

Weather conditions, including rainfall and temperatures, should be considered in the spread of the mosquitoes and, consequently, the virus. Last summer, the virus outbreak affected close to 165 people in Missouri, with five of those cases resulting in death. A University of Missouri researcher at the College of Veterinary Medicine (Dr. Gayle Johnson, veterinarian and associate professor of veterinary pathobiology) has been tracking the virus around the state and predicts that the virus outbreak will be as severe this summer as it was in 2002.

As a gardener, it would help if you are adequately informed about mosquito control measures such as: mosquito surveillance, source reduction, biological control strategies, ground and aerial application of insecticides, and public education.

Recommendations to gardeners to avoid the virus:
• Avoid going outside at dusk or dawn. Many of the mosquitoes that carry the West Nile virus are especially likely to bite around dusk and dawn.

• When possible, wear long- sleeved clothes and long pants treated with insect repellent.

• Apply an insect repellent before working in the garden. Recommended insect repellent contains DEET (N,N-diethyl- meta-toluamide). A higher percentage of DEET should be used if you will be outdoors for several hours, while a lower percentage of DEET can be used if time outdoors will be limited.

• Limit the number of places available for mosquitoes to lay their eggs. Eliminate and empty standing water sources from around your home, such as old tires, logs or containers.

• Consider biological control of mosquito larvae and adult.

• Use live mosquito fish (Gambusia) in ditches and ponds.
• Use birds, bats and dragonflies to control adult mosquitoes.
• Place Mosquito dunks and mosquito bits [biological mosquito larvicide containing Bacillus thuringiensis israelensis (BTI) as active ingredient] on surfaces of garden pond and other areas likely to harbor mosquitoes.
• Apply a few drops of extra virgin olive oil on water surfaces.

• See a doctor if you suspect you have been bitten by a mosquito and are not feeling well.

• Stay updated and educated on the West Nile virus.

For more information, visit websites for National Centers for Disease Control and Prevention (www.cdc.gov/ncidod/dvbid/westnile/ ) and University of Missouri (http://www.missouri.edu/~news/releases/aprmay02/westnile.html ).

Anne Gachuhi, MS
Horticulture Specialist
GachuhiA@missouri.edu

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		Editor: Roxanne T. Miller MillerRT@missouri.edu