Pesticide Spraying for WNV & Asthma

[1] Pesticide Spraying for West Nile Virus Control and Emergency
Department Asthma Visits in New York City, 2000.
[2] Policy Implications -- Spraying on a Summer Night: A Safer Way to
Stop West Nile Virus.

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[1]
PESTICIDE SPRAYING FOR WEST NILE VIRUS CONTROL & EMERGENCY DEPARTMENT
ASTHMA VISITS IN NEW YORK CITY, 2000. Karpati et al. 2004.
Environmental Health Perspectives 112 (11): 1183-1187

<http://ehp.niehs.nih.gov/docs/2004/6946/abstract.html> Link from
abstract page to full text.

Adam M. Karpati,1,2 Mary C. Perrin,3,4 Tom Matte,5 Jessica Leighton,3
Joel Schwartz,6,7 and R. Graham Barr6,8,9
1Division of Disease Control, New York City Department of Health and
Mental Hygiene, New York, New York, USA; 2Epidemiology Program Office,
Centers for Disease Control and Prevention, Atlanta, Georgia, USA;
3Division of Environmental Health, New York City Department of Health
and Mental Hygiene, New York, New York, USA; 4Department of
Environmental Health Sciences, Mailman School of Public Health,
Columbia University, New York, New York, USA; 5National Center for
Environmental Health, Centers for Disease Control and Prevention,
Atlanta, Georgia, USA; 6Channing Laboratory, Department of Medicine,
Brigham and Women's Hospital, Harvard Medical School, Boston,
Massachusetts, USA; 7Division of Environmental Health, Harvard School
of Public Health, Boston, Massachusetts, USA; 8Division of General
Medicine, Department of Medicine, College of Physicians and Surgeons,
and 9Department of Epidemiology, Mailman School of Public Health,
Columbia University, New York, New York, USA

Abstract
Pyrethroid pesticides were applied via ground spraying to residential
neighborhoods in New York City during July-September 2000 to control
mosquito vectors of West Nile virus (WNV). Case reports link pyrethroid
exposure to asthma exacerbations, but population-level effects on
asthma from large-scale mosquito control programs have not been
assessed. We conducted this analysis to determine whether widespread
urban pyrethroid pesticide use was associated with increased rates of
emergency department (ED) visits for asthma. We recorded the dates and
locations of pyrethroid spraying during the 2000 WNV season in New York
City and tabulated all ED visits for asthma to public hospitals from
October 1999 through November 2000 by date and ZIP code of patients'
residences. The association between pesticide application and
asthma-related emergency visits was evaluated across date and ZIP code,
adjusting for season, day of week, and daily temperature,
precipitation, particulate, and ozone levels. There were 62,827 ED
visits for asthma during the 14-month study period, across 162 ZIP
codes. The number of asthma visits was similar in the 3-day periods
before and after spraying (510 vs. 501, p = 0.78). In multivariate
analyses, daily rates of asthma visits were not associated with
pesticide spraying (rate ratio = 0.92; 95% confidence interval,
0.80-1.07). Secondary analyses among children and for chronic
obstructive pulmonary disease yielded similar null results. This
analysis shows that spraying pyrethroids for WNV control in New York
City was not followed by population-level increases in public hospital
ED visit rates for asthma. Key words: asthma, obstructive airway
disease, ozone, particulates, pesticides, pollutants, pyrethroids, West
Nile virus. Environ Health Perspect 112:1183-1187 (2004). [Online 8
July 2004]

Address correspondence to A.M. Karpati, Division of Epidemiology, New
York City Department of Health and Mental Hygiene, 125 Worth St., Room
315, CN-06, New York, NY 10013 USA. Telephone: (646) 253-5700. Fax:
(212) 788-4473. E-mail: akarpati@health.nyc.gov
The authors declare they have no competing financial interests.Received
26 December 2003; accepted 6 July 2004.

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[2]
POLICY IMPLICATIONS OF KARPATI ET AL. STUDY:

SPRAYING ON A SUMMER NIGHT; A SAFER WAY TO STOP WEST NILE VIRUS.
Victoria McGovern. Environmental Health Perspectives 112 (11): A637

<http://ehp.niehs.nih.gov/docs/2004/112-11/ss.html>

A population-level study has shown that night-time pesticide spraying
in the late summer and early fall, aimed at controlling adult
mosquitoes that carry West Nile virus, can be done in a way that does
not drive up the number of people seeking emergency care for
asthma-related problems [EHP 112:1183-1187]. A team led by Adam M.
Karpati, a physician in the New York City Department of Health and
Mental Hygiene, reports that in studies of the city's 2000 mosquito
spraying season, no correlation could be found between broad
application of sumithrin (a pyrethroid pesticide) and asthma cases
presenting at the city's 11 public hospital emergency departments.
NYC 5th Ave.
Big Apple air okay. Mosquito pesticide spraying to prevent West Nile
virus was not associated with an increase in asthma attacks.
image credit: Corel

Earlier studies had shown that high exposure to pyrethroid
pesticides--often in an occupational setting--can trigger reactions in
asthma sufferers ranging from mild symptoms such as sneezing and
scratchy throat to more acute ones such as wheezing, chest tightness,
and even death. But no data have been available showing on a population
scale how the lower-level exposures that come from public health
spraying of pesticides affect the large number of asthmatics that may
live in a big city.

The researchers tabulated data for asthma-related emergency room visits
around the dates when a sumithrin-based pesticide was sprayed in each
of 162 residential zip code areas in the city during July-September
2000. The timing of spraying within each zip code depended on whether
surveillance indicated it was warranted--for example, if a dead bird
were found to be infected with the virus, or if a human case were
identified. A zip code area was rarely sprayed on consecutive days. The
study also incorporated air quality data including daily measures of
ozone, air particulates, and temperature, which can all cause
fluctuations in the number of people seeking treatment for
asthma-related symptoms. For a control, the team used asthma-related
emergency room visits on days prior to spraying. They also looked at
the number of asthma-related emergency room visits before and after the
spraying season.

The researchers found that the number of asthma-related visits in the
three days before application of the pesticide and the three days after
were nearly identical. Looking more specifically within the emergency
department data for asthma flare-ups in children and for aggravation of
chronic obstructive pulmonary disease similarly yielded no correlation
between spraying and symptoms.

The study does not necessarily show that public health pyrethroid
spraying is not a danger to asthmatics. Rather, it could suggest that
the city's method of application and/or the citizens' behavior during
spraying helped minimize exposure. During 2000, the first year when New
York City exclusively used a pyrethroid pesticide, the city limited its
spraying to areas where the virus was detected in birds, mosquitoes, or
humans, with spray trucks usually beginning their rounds near 10 p.m.
and continuing through the night to 5 a.m. Radio, television, and print
media were used to alert residents 48 hours prior to any spraying and
to instruct people to remain indoors and close their windows during the
hours when spraying would occur.

[Thanks to Suzanne Snedeker for bringing these articles to our
attention.]

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Received on Fri Aug 6 14:00:10 2004