Our sister city to the north, Dallas, is suffering through a severe outbreak of West Nile virus among humans this summer. They've had about 700 confirmed cases and 10 deaths as a result of the disease. Consequently, the mayor has decided that it is time for drastic action. He has declared a state of emergency and has authorized the start of aerial spraying of the county for the mosquito which delivers the virus to humans. This will be the first use of aerial spraying for the mosquito in the county since 1966 and it does, of course, raise some environmental concerns.
The full effects of the insecticide used are open to question. It may, for example, kill many other insects besides mosquitoes, both "good" insects like butterflies and bees as well as "bad" insects. And what about the domino effect? What might be the damage up the food chain to the wildlife that depend on those insects as a part of their diet - birds, bats, frogs, e.g.? And what are the full implications of the spraying for humans who may be vulnerable - pregnant women, the elderly or chronically ill, e.g.? It's a complicated question, but ten people have already died there and across the state there have been a total of sixteen fatalities this summer. Officials are making the gamble that the benefits of the spraying to human life will outweigh the damage that it may do to the environment.
While the prevalence of the disease among humans in Dallas is noteworthy and worrisome, I have not heard of any unusual outbreaks of West Nile among birds this summer. There are always some deaths from the virus and in some summers I've even found one or more dead birds in my yard that I suspected might have been West Nile victims, but I haven't seen any dead birds here so far this summer.
What can you do to help prevent the disease? The best advice is to just make sure there are no standing water breeding grounds for mosquitoes in your yard. Moreover, if you do find a bird that is dead from unknown causes, especially a member of the Corvid family that is highly susceptible to the disease such as a jay or a crow, it would be a good idea to contact your local Health Department to see if they are testing dead birds for West Nile. Also, it is always good practice not to touch such animals with your bare hands.