Letter from the California Department of Health
Services Published in Bulletin of World Health Organization 2001, 79 (9)
Re: Aircraft disinsection
Editor
- Gratz et al. (1) advocate the
disinsection of aircraft flying from airports in tropical disease endemic areas
into nonendemic areas. The authors reflect WHO's position in recommending the
use of pyrethroid insecticides on the basis of efficacy, cost-effectiveness, and
absence of adverse health effects to humans. Vector-borne diseases are global
public health issues and their control is essential, but it is erroneous to
state that the recommended pyrethroid insecticides are not of toxicological
concern and are safe to use around humans.
The health effects of pyrethroids include dermal
paresthesia, exacerbation of pre-existing asthma and, at high doses, excitatory
neurotoxicity (2). Airline passengers may not associate the adverse effects they
experience with pesticide exposure aboard aircraft because they are unaware of
the exposure and do not recognize the signs and symptoms of pesticide-related
illness, and several hours may elapse before the onset of symptoms (3). Children
may be especially susceptible to such adverse effects.
WHO's statement (4) that pyrethroids on aircraft
are unlikely to precipitate pre-existing diseases contradicts existing
literature. Studies suggest that asthmatic patients respond to inhalation
exposure to pyrethroids with airway hyper-responsiveness and that even "low
irritant" aerosols may trigger nose and eye symptoms (5).
The California Department of Health Services (CDHS)
conducts ongoing surveillance of occupational pesticide illness. Pyrethroid
pesticides accounted for 119 of 776 (15%) occupational pesticide illness cases
reported in 1998 and 1999 (6). Adverse health effects of pyrethroids were
dermatological (22%), ocular (34%), respiratory (19%), gastrointestinal (69%),
and neurological (73%). During this two- year period, permethrin, a pyrethroid
recommended for aircraft disinsection, accounted for 16 cases (13%) of
occupational pyrethroid illnesses reported.
CDHS has received reports of occupational
illnesses among flight attendants. While dermal uptake of pyrethroids is low
(2), exposure in an enclosed environment may enhance absorption by dermal
exposure, inhalation, and ingestion. Furthemore, the half-life of pyrethroids
may be prolonged by the absence of ultraviolet light aboard aircraft. Flight
crew may have significant acute inhalation and dermal exposures because they are
physically active and touch many surfaces during the course of their work. Both
staff and passengers who fly frequently may incur significant cumulative
exposures.
Solvents and other inert ingredients in pesticide
formulations may contribute to the adverse effects of pyrethroids (5). There is
little toxicological information available about these ingredients but, rather
than constituting evidence that health effects are nonexistent, the absence of
data identifies gaps that need to be filled prior to encouraging the continued
practice of aircraft disinsection by pyrethroid application, especially while
passengers and crew are on board.
With ample evidence to demonstrate that exposure
to pyrethroid pesticides may result in adverse health effects, especially among
sensitive subpopulations, there is insufficient information to determine that
aircraft disinsection as currently practiced is safe. We believe that
reconsideration of the use of pesticides as described by Gratz et al. is
warranted, in order to ensure the safety of passengers and crew while preventing
transmission of vector-borne diseases through air travel.
Rupali
Das, Public Health Medical Officer
Occupational Health Branch
California Department of Health Services
and Assistant Clinical Professor
Division of Occupational and Environmental Health
Department of Medicine
University of California, San Francisco, USA
James
Cone, Chief
Occupational Health Branch
California Department of Health Services
Patrice
Sutton, Research Scientist
Public Health Institute
Acknowledgements
Funding for work described in this letter was provided by the US National
Institute for Occupational Safety and Health, the US Environmental Protection
Agency, and the State of California.
Conflicts of interest: none declared.
- Gratz
NG, Steffen R, Cocksedge W. Why aircraft disinsection? Bulletin of the
World Health Organization, 2000, 78: 995-1004.
-
Ray DE. Pesticides derived from plants and other
organisms. In: Hayes WJ, Laws ER, eds. Handbook of pesticide toxicology.
Vol. 2. San Diego, Academic Press, 1991.
-
He F et al. Clinical manifestations and diagnosis of
acute pyrethroid poisoning. Archives of Toxicology. 1989, 63:
54-58.
- Report on
the Informal Consultation on Aircraft Disinsection. Geneva, World Health
Organization, 1995 (unpublished document WHO/IPCS/ 95.51).
-
Salome CM et al. The effect of insecticide aerosols on
lung function, airway responsiveness and symptoms in asthmatic subjects.
European Respiratory Journal 2000, 16: 38-43.
- CDHS.
Sentinel Event Notification System for Occupational Risk: occupational
pesticide poisoning - California, Year 3. San Francisco, California
Department of Health Services, 2001 (unpublished document)
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