[BCNnet] West Nile update

[Judy Pollock]

A note from the BCN West Nile Task Force:

Since the mosquito season will soon be upon us, we thought we'd send around a
summary of some of the research about the disease that has emerged over the
winter, as well as a suggested "action item": There is broad agreement that
larviciding of sources of stagnant water such as catchbasins early in the
season, before mosquitos hatch out, is the best way to fight this disease that
is so devastating to birds and people. This should greatly reduce the need for
the later spraying of adult mosquitoes, which is much more damaging to
ecosystems.

If you want to help, you can contact your municipality to make sure they
have a
plan to larvicide soon, and also a plan to monitor adult mosquitoes for the
disease, so that spraying is not undertaken without good reason. Find out who 
is doing the testing. Is it the same people who will be paid to do the
spraying? That's not so good. Kim Stone at Safer Pest Control is working on
this issue, and could advise you if you have concerns about what you find out.
(312 641-5575) You might also find out if there would be prohibitions on
spraying natural areas, which might have much more damaging environmental
consequences than spraying a neighborhood (depending on the location).

We've also attached Audubon's recommendations regarding mosquito control.
Since
these were published we've been told that there is little difference between
synthetic and bacterial larvicide in its environmental impact, but that the 
bacterial is hugely more expensive because it needs to be reapplied each
month.
Most places seem to be choosing the synthetic - that may not be such a bad
thing.

Notes from current WNV research
WNV Fatalities in 2002: 
241 humans, 4300 horses 
14,122 birds tested positive represent "only the tip of the iceberg; the 
actual number is probably 100-1000 times higher) Nick Komar, CDC

Human fatalities in NYC: 
1999:61 
2000: 14 
2001: 14 
2002: 80 Most of the first three year's cases were in the epicenter of the
five
boroughs; in the fourth year, the disease moved out from the epicenter.

>From Peter Marra, Smithsonian: 
"Thus far, West Nile Virus has been thought of as being a disease that
primarily [afflicts] crows. We believe this to be questionable and the result
simply of a sampling bias. We really have no evidence of what the actual
prevalence is in the wild."

>From Nick Komar, CDC: 
95-100% of crows and magpies infected under lab conditions died; House Finch
also showed high mortality.

>From Audubon-Chicago Region/BCN: 
Chickadees and crows all but disappeared from areas that coincided with the
human cluster sites from August through November. In the region's December
Christmas Counts, crow numbers had decreased 81% from their 11-year average, 
blue jays 66 percent, and black-capped chickadees 35%.

Cornel Lab of Ornithology analyzed FeederWatch data based on these findings,
and found 91% fewer crow reports and 26% fewer chickadee reports in Illinois.

Additional research facts: It has been shown that birds which ingest infected
prey become infected, and evidence now exists that birds pass the disease
through droppings. It is not known whether humans can be infected by handling 
or eating infected birds but precautions are advised.

36 species of mosquitoes are known vectors. The four main ones are culex
pipiens, c. restuans, c. quinquefasciata, and c. salinarious. The first three
are highly efficient container breeders; the fourth is found in marshes and
lakes.

Douglas Causey, PhD, Harvard University Museum of Comparative Zoology: The
problem with looking at the disease picture from a strictly human
standpoint is
that we and animals are all in this together. . Last year, avian deaths 
increased five-fold over 2001. West Nile Virus has spread to the Caribbean in
2003, and it now is a leading suspect in the disturbing 10-fold drop in
several
bird species in Costa Rica over the past year. Many of these are migratory 
songbirds, the loss of which will be noted across the United States.

For more current and thorough information, check out
www.audubon.org/bird/wnv. 
This site contains links to other useful pages, particularly abstracts from a
conference that was held at the Smithsonian this winter. For local analysis,
see http://www.chicagowildernessmag.org/issues/spring2003/spraydebate.html.

Audubon's Recommendations for Management of Mosquitoes

The National Audubon Society recommends that health and pest control
authorities in affected states employ an integrated approach to the management
of mosquitoes carrying the West Nile Virus. This means using targeted 
mosquito spraying only as a last resort for control of West Nile virus.
Reducing mosquito breeding grounds and using bacterial larvicide in bodies of
water are less toxic and often more effective means of control. These are the
recommended first lines of defense.

Compounds such as Anvil that are used in aerial sprayings are toxic to fish
and
also to invertebrate animals including beneficial insects, which are also
important food sources for wildlife. The risks need to be weighed against the 
impact of the disease.

Audubon Senior Vice President of Science Dr. Frank Gill stated: "West Nile
Virus is a disease that, unfortunately, has come to stay in the Western
Hemisphere. It affects people, horses, bats and other small mammals, and our
native birds. While more than 99 percent of West Nile cases turn out to be
completely harmless, the risk of West Nile nationwide has caused
communities to
take prudent measures against the mosquitoes that carry the disease. Our 
experience with West Nile in the Northeast shows that an integrated
approach to
pest management is the most effective and safest method available. Audubon
advises states to enact measures that will quickly effect this change. It 
will greatly help people, other mammals, and the birds which are the disease's
primary victims."

Integrated pest management calls for elimination of mosquito breeding habitat,
the use of environmentally sound tools to combat the insects, and a more
targeted approach to the use of pesticides. "Communities can greatly enhance 
their ability to eliminate the threat of disease-carrying mosquitoes by
replacing chemical larvacides with bacteria-based products, which kill
mosquitoes, but not beneficial insects, such as dragonflies; amphibians; and
fish that prey upon mosquitoes," Gill continued. "By eliminating pools of
stagnant water in parks and at dumps, and by allowing some drainage of dammed
areas, communities also decrease the available breeding ponds for mosquitoes.
Homeowners can help; cleaning out gutters and removing tarps, tires, and other
objects where water can collect also prevents osquitoes from reproducing."

"Aerial spraying of pesticides has been shown to be less effective than
targeted, localized spraying. If pesticides are to be employed, a focused,
limited, and timely response works best. Combining this approach with the use 
of highly effective bacterial larvacides and community and home cleanup of
standing water is the most effective and efficient use of our states' energies
and limited resources."

Summary of IPM approach:
1. Public Education 
2. Reducing breeding grounds 
3. Monitoring and surveillance of mosquito populations 
4. Bacterial larvicide 
5. Targeted spraying only as a last resort

If you are interested in becoming involved with task force activities, let me
know.

Judy

Judy Pollock
Evanston (Cook)
bobolnk@ix.netcom.com