Boston's response, 9-02

Boston’s Response to West Nile Virus by Linda Hillyer

What Is West Nile Virus?
West Nile virus (WNv) is a mosquito-borne virus endemic to Africa, West Asia, and parts of
Europe. It was first identified in the United States during the summer of 1999 when a large
number of birds were found dead in the New York City area. Out of a population of more than 7
million, 62 people — or less than .0009% — became ill with the virus, 7 of whom died 1. By
comparison, 2,600 people died of the flu in New York City during the same year 2.

A person can be infected with WNv when bitten by an infected mosquito. Once infected, a
person may experience a wide range of symptoms, from what resembles a mild flu to meningitis,
encephalitis, or sometimes death. Most who are infected, however, do not develop noticeable
symptoms 3. Less than 1% develop severe neurological disease 4. The greatest risk for serious
illness is among the elderly and those with compromised immune systems 5.
West Nile Virus and Boston
WNv was first identified in the Boston area in July 2000 when a dead crow was found near
Willow Pond. As of mid-November of that year, a total of 442 birds had died in Massachusetts
due to infection from the virus, and one horse had developed severe neurological disease. There
were, however, no reported cases in Massachusetts of human infection 6.
When birds in the Boston area began dying from WNv infection, the response of public-health
and other local officials was swift: Suffolk County Mosquito Control began applying pesticides
in local neighborhoods and public spaces, and the city set up a hotline to field the public’s
questions and concerns. Some residents were relieved by the response; others were alarmed at
being exposed to chemicals that they believed to be toxic, especially since notification of their
use was thought to be inadequate.
The Neighborhood Pesticide Action Committee (NPAC) was born out of the latter set of
concerns. This small, but quickly growing, group of residents from the Jamaica Plain area
worked tirelessly throughout the fall and winter to educate their neighbors and public officials
about WNv, the dangers of pesticides, and the use of ecologically sound alternatives. By early
spring, NPAC had urged the Jamaica Plain Neighborhood Council to pass a resolution requesting
the Boston Public Health Commission (BPHC) to implement safer alternatives in place of
pesticide spraying for the virus.
That same spring, BPHC funded NPAC and eight other community-based organizations to
educate Boston residents about WNv prevention. The summer-long campaign consisted of the nine
organizations instructing residents about protective measures they could take — from keeping
mosquitoes out of their homes to eliminating mosquito-breeding sites around their neighborhoods
— as an alternative to pesticide use. BPHC stated that pesticides would not be sprayed as long as
there were no known human cases of the disease; the hope was that, with a well-educated public,
the disease could be contained enough such that no people would become infected. The campaign
was considered a success: not only was the public well educated in WNv prevention, but no human
cases of the disease were reported in the areas of Boston that had been considered most vulnerable
to it 7.
NPAC conducted another highly successful campaign last summer. The community-based
organization informed local residents about a little-publicized law that allows residents to request
their property not be sprayed with pesticides except in the case of a public-health emergency.
NPAC collected well over 500 signed requests from residents living throughout Jamaica Plain.
This enthusiastic response to NPAC’s “no-spray campaign” forced Suffolk County Mosquito
Control to concede by August 2001 that Jamaica Plain had become virtually off-limits to the use of
pesticide spraying as the area’s method of mosquito control.
About the Pesticides
During the summer of 2000, several pesticides were applied in the neighborhoods and public
spaces of the Jamaica Plain area. Scourge, intended to kill adult mosquitoes, was sprayed from
trucks, and Altosid, intended to kill mosquito larvae or pupae, was dropped in the form of
“briquets” in local catch basins. Permethrin 10EC was sprayed once by hand around Daisy Field.
Although during the summer of 2001 neither Scourge nor Permethrin were sprayed for WNv in
the Jamaica Plain area, the larvicide Altosid was again applied to catch basins. Targeted use of
larvicides is generally considered safer than spraying adulticides, which kill adult mosquitoes,
but it does carry risks. Not only does Altosid contain at least one toxic chemical (see the more
detailed description of Altosid below), but in Boston, many of the catch basins into which the
larvicide was dropped empty into the city’s waterways, including the Neponset and Charles
rivers and Boston Harbor.
What They’re Made Of
Scourge contains 18% resmethrin (the pesticide’s “active ingredient”), 54% piperonyl
butoxide, and 20% aromatic petroleum solvent. The remaining 8% are a trade secret 8.
Permethrin, Permethrin 10EC’s active ingredient, makes up only 10% of the pesticide. The
remaining 90% is petroleum distillate 9. Both resmethrin and permethrin are pyrethroids,
synthetic versions of the insecticides that naturally occur in chrysanthemums. Pyrethroids retain
the insecticidal effects of their natural counterparts but are much longer acting 10.
Resmethrin is said to be “slightly toxic to practically non-toxic” to humans 11, and permethrin is
described as having “low- to moderate” toxicity to humans for short-term exposures 12.
Permethrin, however, has been classified by the EPA as a possible human carcinogen 13, and
both pesticides have been identified as hormone disruptors and as interfering with normal
reproduction and development in laboratory animals 14. In addition, pyrethroids as a group have
been reported to adversely affect the peripheral and the central nervous systems, some even
causing seizures in cases of severe poisoning 15.
Pyrethroids are highly toxic to bees, fish, frogs, and many other organisms, some of which are
natural mosquito predators 16. Such organisms are endangered whenever pyrethroids are sprayed
into the environment, since sprayed pesticides inevitably hit other wildlife besides the targeted
mosquitoes.
Although when acting on its own the acute toxicity of piperonyl butoxide (PBO) has been
reported to be low 17, the EPA has classified it as a possible human carcinogen 18. Within
Scourge, PBO functions as a “synergist,” which means that it makes Scourge much more potent
than it would be were resmethrin acting alone 19. It does this by inhibiting liver enzymes that are
responsible for the breakdown of certain toxins, causing people and other organisms to become
vulnerable to them.
The aromatic petroleum solvent found in Scourge can be allergenic and, when inhaled, may
cause chemical pneumonia. The components that give the solvent its aroma have been identified
as possible carcinogens 20.
The active ingredient in Altosid is methoprene, an “insect growth regulator” that prevents
mosquito larvae from developing into mature adults. Methoprene’s acute toxicity to mammals is
considered low, but it is highly toxic to amphibians and certain invertebrates. It may also harm
fish 21. Methoprene makes up only 8.62% of Altosid; the manufacturer lists the remaining
91.38% as “inert ingredients” 22. So-called inert ingredients identified in other pesticide
formulations are known or suspected carcinogens or nervous-system depressors 23.
Ecologically Sound Alternatives
Ironically, widespread use of pesticides creates some of the very conditions it is intended to
protect us against: It poses significant risks to our health, especially that of fetuses and small
children who are particularly vulnerable to even minute chemical exposures 24. Additionally, it
may actually increase mosquito populations over the long term by killing natural mosquito
predators and developing resistance to the pesticides in the mosquitoes themselves 25.
Ecologically sound methods — methods that are safer for both people and the environment —
have been put into practice in a number of communities. Targeting mosquitoes at their breeding
sites, one of the methods that was used by Boston during the summer of 2001, is the most
effective approach and environmentally the least harmful. In some cases, breeding sites can be
eliminated altogether; for example, old tires, which collect water, thus creating excellent
breeding conditions for some species of mosquitoes (including those that carry West Nile virus),
can be discarded 26. Sites can also be made inhospitable, for instance, by removing or treating
sewage leaks, which also create excellent breeding conditions for these species of mosquitoes. In
still other cases, mosquito predators can be introduced. Fish that feed on mosquito larvae have
long been used successfully in many parts of the world. Certain insects can also be effective, as
are a number of bacteria, fungi, and protozoa. However, even these biological controls must be
used judiciously, since they interfere with the natural balance of the environment. Extensive
monitoring of infected mosquitoes and a thorough understanding of their habitats are vital to the
success of any mosquito-control program 27.
Another alternative was tried and proven effective right here in the Greater Boston area. During
the summer of 2001, Jamaica Plain’s neighboring town of Newton used Bacillus sphericus
experimentally — and with great success — as an alternative to the larvicide Altosid. The
bacteria was used in a one-time application in 40 of the town’s catch basins. Six weeks following
the application, 95 percent of mosquito larvae had been killed and throughout the summer there
was no need to reapply the agent. Its cost was about one-third that of Altosid 28.

What You Can Do
You can make a big difference in protecting yourself and your neighbors from West Nile virus
infection. To cut down on the number of mosquitoes around your home, eliminate potential
breeding sites: because the mosquitoes that carry West Nile virus breed in standing water,
regularly empty or turn over containers such as wheelbarrows, ceramic pots, old tires, and trash
bins; clean out roof gutters; and keep swimming pools and birdbaths clean. To keep mosquitoes
out of your home, repair all screens and make sure they are well attached to their frames. To
prevent mosquitoes from biting you, avoid going outdoors between dusk and dawn if possible.
If you cannot avoid doing so, wear a long-sleeved shirt, long pants, and socks, and apply a
mosquito repellent. Repellents that contain the insecticide N-N-diethyl-meta-toluamide (DEET)
are generally considered the most effective but not necessarily the safest; use them with caution.
A range of safer alternatives is available, from essential oils to commercially formulated
products 29.
We must also tell public officials about our concerns. To ensure that pesticides are not used
this season, let public officials know that you would like ecologically sound measures to be
taken to protect you and your community from West Nile virus. This includes the application of
the alternative larvicide Bacillus sphericus (B.s.): The experimental use of B.s. in Newton last
summer was so successful that the Boston Public Health Commission has decided to use it this
summer in catch basins that empty into so-called sensitive areas — wetlands, such as Jamaica
Pond and the Muddy and Neponset rivers. For budgetary reasons, however, BPHC does not plan
to switch over to Altosid entirely until next summer; although B.s. is less expensive than Altosid,
BPHC would like to use up the large store of Altosid that it still has on hand. Remind public
officials that Altosid contains the toxic chemical methoprene as well as many “inert ingredients”
and that you would like to see it replaced throughout Boston as soon as possible 30.
You may also want to sign one of NPAC’s “no-spray pledge cards,” which requests of the city
that your property not be sprayed with pesticides except in the case of a public-health
emergency. In doing so, you will be joining more than 500 other local residents who have
already made this request. You will be protecting your property from unwanted pesticides and
alerting public officials that you would like your community and the city to use ecologically
sound methods of mosquito control.
We Must Remain Vigilant
Despite our success in preventing the need for pesticide spraying last summer, WNv did infect
three Massachusetts residents, one of whom died. Horses, mosquitoes, and many species of birds
were also infected with the virus 31. By the end of May of this year, WNv-infected birds had
already been identified in New Jersey, New York, Pennsylvania, Georgia, District of Columbia,
Florida, Virginia, and Massachusetts. As of early September, four Massachusetts residents had
contracted WNv from “in-state” exposures 32.
WNv is still very much with us, and prevention is an ongoing challenge and responsibility. The risk of human infection is usually low before late summer, according to the Massachusetts Department of Public Health, but Boston residents must remain vigilant: it is important that we take precautionary measures throughout the season to reduce our risk during the summer months33. Sources
1. John N. Goldman, M.D. “West Nile Virus: A New Threat in Pennsylvania,” Pennsylvania
MEDICINE, Summer 2000.
2. Juan Gonzalez, “City Beat: Cure’s More Deadly Than the Disease,” Daily News, online
edition, 7/25/00. Flu-death figure was given by Karl Coplan of the Pace Environmental
Litigation Clinic, who in turn was quoting Dr. Neal Cohen, commissioner of New York City
Department of Health, speaking at a hearing.
3. Rachel Massey, “West Nile Virus, Part 1,” Rachel’s Environment & Health Biweekly, #709,
October 12, 2000 (Annapolis, MD: Environmental Research Foundation). Back issues available
by e-mail: erf@rachel.org.
4 .CDC MMWR, 11/24/00 (in “Editor’s Note”).
5. Massey, “West Nile Virus, Part 1.”
6. “Update: West Nile Virus Activity — Eastern United States, 2000,” CDC Morbidity and
Mortality Weekly Report, November 24, 2000, Vol. 49, No. 46, pp. 1044-1047.
7. Andy Epstein, RN, MPH, and Suzanne Strickland, MPH, “WNV Year 2001: Boston Public
Health Commission Response,” October 3, 2001.
8. Aventis Environmental Science, “Material Safety Data Sheet,” November 2000.
9. Clarke Mosquito Control Products, Inc., “Material Safety Data Sheet,” May 4, 1999.
10. National Coalition Against the Misuse of Pesticides (NCAMP), “chemicalWATCH
Factsheet,” Vol. 10, No. 1, March 1990.
11. EXTOXNET (Extension Toxicology Network), “Pesticide Information Profiles:
Resmethrin,” Revised June 1996.
Available at http://ace.orst.edu/cgi-bin/mfs/01/pips/resmethr.htm.
12. National Pesticide Telecommunications Network (co-sponsored by Oregon State University
and the U.S. Environmental Protection Agency), “Permethrin,” 1/17/01.
Available at http://ace.orst.edu/info/nptn/factsheets/perm7.htm.
13. Audrey Thier, “Mosquito Control Pesticides,” The Toxic Treadmill: Pesticide Use and Sales
in New York State, 1997-1998, October 2000 (Albany, NY: Environmental Advocates and New
York Public Interest Research Group). Available at www.envadvocates.org.
14. Ted Schettler, M.D., Gina Solomon, M.D., Maria Valenti, and Annette Huddle, Generations
at Risk: Reproductive Health and the Environment (Cambridge, Mass.: MIT Press, 1999), pp.
135 and 186.
15. United States Environmental Protection Agency, Office of Pesticide Programs, “Recognition
and Management of Pesticide Poisoning, 5th Edition,” updated September 15, 1999, pp. 87-88.
Available at www.epa.gov/pesticides/safety/healthcare/handbook.htm.
16. Eric Kiviat, “Mosquito Ecology, and Management of Mosquitoes and People,” News from
Hudsonia, Vol. 10, No. 1, February 1994, p. 3.
17. NCAMP, “chemicalWATCH Factsheet,” Vol. 10, No. 3, August 1990.
18. Massey, “West Nile Virus, Part 1”; NCAMP, Technical Report, Vol. 9, Nos. 8/9,
August/September, 1994.
19. NCAMP “chemicalWATCH Factsheet,” August 1990.
20. NCAMP “chemicalWATCH Factsheet,” March 1990.
21. Carrie Swadener, “Managing Mosquitoes without Poisons,” Journal of Pesticide Reform,
Winter 1993, Vol. 13, No. 4 (Eugene, OR: Northwest Coalition for Alternatives to Pesticides);
NCAMP, “chemicalWATCH,” Pesticides and You, August 1986.
22. Wellmark International, “Material Safety Data Sheet,” May 2000.
23. Mueller-Beilschmidt, “Toxicology and Environmental Fate of Synthetic Pyrethroids,”
Journal of Pesticide Reform, Vol. 10, No. 3, p. 33.
24. Massey, “West Nile Virus, Part 1.”
25. NCAMP, “Mosquitoes: Integrated Pest Management for Homes and Communities,” 1998.
26. Massachusetts Department of Public Health, “Steps You Can Take to Prevent West Nile
Virus Encephalitis,” April 2000.
27. NCAMP, “Mosquitoes: Integrated Pest Management for Homes and Communities”; Carrie
Swadener, “Community Mosquito Control,” Journal of Pesticide Reform, Summer 1994, Vol.
14, No. 2 (Eugene, OR: Northwest Coalition for Alternatives to Pesticides); Dynamac
Corporation, Rockville, MD, “National Park Service IPM Information Package: Mosquitoes,
Final Report,” 27 July 1984, pp. XXI-7–XXI-14.
28. NPAC conversation with Dave Henley, Middlesex County Mosquito Control, April 29, 2002.
29. Massachusetts Department of Public Health, “Public Health Fact Sheet: West Nile Virus
Encephalitis,” April 2002. Available at http://www.state.ma.us/dph/cdc/factsheets/fswnv.pdf;
Swadener, “Managing Mosquitoes without Poisons”; “Tools for Green Living: Resources for
Eco-Awareness and Action, E Magazine, May/June 2000”; Chris Hayhurst, “Keeping Bugs at
Bay: Banning the Biters with Natural Insect Repellents,” E Magazine, July/August 2000.
30. NPAC communication with Leon Bethune, Office of Environmental Health, Boston Public
Health Commission, June 27, 2002.
31. Massachusetts Department of Public Health, “Public Health Fact Sheet: West Nile Virus
Encephalitis,” April 2002. Available at http://www.state.ma.us/dph/cdc/factsheets/fswnv.pdf.
32. “West Nile Virus Found in Birds of Four States,” Boston Metro, May 24, 2002, p. 2;
Massachusetts Department of Public Health, “West Nile Virus Detected in Massachusetts,”
September 9, 2002. Available at http://www.state.ma.us/dph/media/2002/pr0524.htm;
Massachusetts Department of Public Health, “2002 West Nile Virus Update.” Available at
http://db.state.ma.us/dph/wnile.
33. Massachusetts DPH, “West Nile Virus Detected in Massachusetts,” May 24, 2002.

Source: http://www.npacboston.org/documents/BostonResponse_9-02.pdf